xref: /frameworks/base/core/java/android/content/res/Resources.java

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.content.res;

import android.animation.Animator;
import android.animation.StateListAnimator;
import android.annotation.AnimRes;
import android.annotation.AnyRes;
import android.annotation.ArrayRes;
import android.annotation.AttrRes;
import android.annotation.BoolRes;
import android.annotation.ColorInt;
import android.annotation.ColorRes;
import android.annotation.DimenRes;
import android.annotation.DrawableRes;
import android.annotation.FractionRes;
import android.annotation.IntegerRes;
import android.annotation.LayoutRes;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.PluralsRes;
import android.annotation.RawRes;
import android.annotation.StringRes;
import android.annotation.StyleRes;
import android.annotation.StyleableRes;
import android.annotation.XmlRes;
import android.content.pm.ActivityInfo;
import android.graphics.Movie;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.Drawable.ConstantState;
import android.graphics.drawable.DrawableInflater;
import android.icu.text.PluralRules;
import android.os.Build;
import android.os.Bundle;
import android.os.Trace;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.LocaleList;
import android.util.Log;
import android.util.LongSparseArray;
import android.util.Pools.SynchronizedPool;
import android.util.Slog;
import android.util.TypedValue;
import android.util.Xml;
import android.view.ViewDebug;
import android.view.ViewHierarchyEncoder;

import com.android.internal.util.GrowingArrayUtils;
import com.android.internal.util.XmlUtils;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Locale;

/**
 * Class for accessing an application's resources.  This sits on top of the
 * asset manager of the application (accessible through {@link #getAssets}) and
 * provides a high-level API for getting typed data from the assets.
 *
 * <p>The Android resource system keeps track of all non-code assets associated with an
 * application. You can use this class to access your application's resources. You can generally
 * acquire the {@link android.content.res.Resources} instance associated with your application
 * with {@link android.content.Context#getResources getResources()}.</p>
 *
 * <p>The Android SDK tools compile your application's resources into the application binary
 * at build time.  To use a resource, you must install it correctly in the source tree (inside
 * your project's {@code res/} directory) and build your application.  As part of the build
 * process, the SDK tools generate symbols for each resource, which you can use in your application
 * code to access the resources.</p>
 *
 * <p>Using application resources makes it easy to update various characteristics of your
 * application without modifying code, and&mdash;by providing sets of alternative
 * resources&mdash;enables you to optimize your application for a variety of device configurations
 * (such as for different languages and screen sizes). This is an important aspect of developing
 * Android applications that are compatible on different types of devices.</p>
 *
 * <p>For more information about using resources, see the documentation about <a
 * href="{@docRoot}guide/topics/resources/index.html">Application Resources</a>.</p>
 */
public class Resources {
    static final String TAG = "Resources";

    private static final boolean DEBUG_LOAD = false;
    private static final boolean DEBUG_CONFIG = false;
    private static final boolean TRACE_FOR_PRELOAD = false;
    private static final boolean TRACE_FOR_MISS_PRELOAD = false;

    private static final int LAYOUT_DIR_CONFIG = ActivityInfo.activityInfoConfigToNative(
            ActivityInfo.CONFIG_LAYOUT_DIRECTION);

    private static final int ID_OTHER = 0x01000004;

    private static final Object sSync = new Object();

    // Information about preloaded resources.  Note that they are not
    // protected by a lock, because while preloading in zygote we are all
    // single-threaded, and after that these are immutable.
    private static final LongSparseArray<ConstantState>[] sPreloadedDrawables;
    private static final LongSparseArray<ConstantState> sPreloadedColorDrawables
            = new LongSparseArray<>();
    private static final LongSparseArray<android.content.res.ConstantState<ComplexColor>>
            sPreloadedComplexColors = new LongSparseArray<>();

    /** Size of the cyclical cache used to map XML files to blocks. */
    private static final int XML_BLOCK_CACHE_SIZE = 4;

    // Pool of TypedArrays targeted to this Resources object.
    final SynchronizedPool<TypedArray> mTypedArrayPool = new SynchronizedPool<>(5);

    // Used by BridgeResources in layoutlib
    static Resources mSystem = null;

    private static boolean sPreloaded;

    /** Lock object used to protect access to caches and configuration. */
    private final Object mAccessLock = new Object();

    // These are protected by mAccessLock.
    private final Configuration mTmpConfig = new Configuration();
    private final DrawableCache mDrawableCache = new DrawableCache(this);
    private final DrawableCache mColorDrawableCache = new DrawableCache(this);
    private final ConfigurationBoundResourceCache<ComplexColor> mComplexColorCache =
            new ConfigurationBoundResourceCache<>(this);
    private final ConfigurationBoundResourceCache<Animator> mAnimatorCache =
            new ConfigurationBoundResourceCache<>(this);
    private final ConfigurationBoundResourceCache<StateListAnimator> mStateListAnimatorCache =
            new ConfigurationBoundResourceCache<>(this);

    /** Used to inflate drawable objects from XML. */
    private DrawableInflater mDrawableInflater;

    /** Lock object used to protect access to {@link #mTmpValue}. */
    private final Object mTmpValueLock = new Object();

    /** Single-item pool used to minimize TypedValue allocations. */
    private TypedValue mTmpValue = new TypedValue();

    private boolean mPreloading;

    // Cyclical cache used for recently-accessed XML files.
    private int mLastCachedXmlBlockIndex = -1;
    private final int[] mCachedXmlBlockCookies = new int[XML_BLOCK_CACHE_SIZE];
    private final String[] mCachedXmlBlockFiles = new String[XML_BLOCK_CACHE_SIZE];
    private final XmlBlock[] mCachedXmlBlocks = new XmlBlock[XML_BLOCK_CACHE_SIZE];

    final AssetManager mAssets;
    final ClassLoader mClassLoader;
    final DisplayMetrics mMetrics = new DisplayMetrics();

    private final Configuration mConfiguration = new Configuration();

    private PluralRules mPluralRule;

    private CompatibilityInfo mCompatibilityInfo = CompatibilityInfo.DEFAULT_COMPATIBILITY_INFO;

    static {
        sPreloadedDrawables = new LongSparseArray[2];
        sPreloadedDrawables[0] = new LongSparseArray<>();
        sPreloadedDrawables[1] = new LongSparseArray<>();
    }

    /**
     * Returns the most appropriate default theme for the specified target SDK version.
     * <ul>
     * <li>Below API 11: Gingerbread
     * <li>APIs 11 thru 14: Holo
     * <li>APIs 14 thru XX: Device default dark
     * <li>API XX and above: Device default light with dark action bar
     * </ul>
     *
     * @param curTheme The current theme, or 0 if not specified.
     * @param targetSdkVersion The target SDK version.
     * @return A theme resource identifier
     * @hide
     */
    public static int selectDefaultTheme(int curTheme, int targetSdkVersion) {
        return selectSystemTheme(curTheme, targetSdkVersion,
                com.android.internal.R.style.Theme,
                com.android.internal.R.style.Theme_Holo,
                com.android.internal.R.style.Theme_DeviceDefault,
                com.android.internal.R.style.Theme_DeviceDefault_Light_DarkActionBar);
    }

    /** @hide */
    public static int selectSystemTheme(int curTheme, int targetSdkVersion, int orig, int holo,
            int dark, int deviceDefault) {
        if (curTheme != 0) {
            return curTheme;
        }
        if (targetSdkVersion < Build.VERSION_CODES.HONEYCOMB) {
            return orig;
        }
        if (targetSdkVersion < Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
            return holo;
        }
        if (targetSdkVersion < Build.VERSION_CODES.CUR_DEVELOPMENT) {
            return dark;
        }
        return deviceDefault;
    }

    /**
     * @return the inflater used to create drawable objects
     * @hide Pending API finalization.
     */
    public final DrawableInflater getDrawableInflater() {
        if (mDrawableInflater == null) {
            mDrawableInflater = new DrawableInflater(this, mClassLoader);
        }
        return mDrawableInflater;
    }

    /**
     * Used by AnimatorInflater.
     *
     * @hide
     */
    public ConfigurationBoundResourceCache<Animator> getAnimatorCache() {
        return mAnimatorCache;
    }

    /**
     * Used by AnimatorInflater.
     *
     * @hide
     */
    public ConfigurationBoundResourceCache<StateListAnimator> getStateListAnimatorCache() {
        return mStateListAnimatorCache;
    }

    /**
     * This exception is thrown by the resource APIs when a requested resource
     * can not be found.
     */
    public static class NotFoundException extends RuntimeException {
        public NotFoundException() {
        }

        public NotFoundException(String name) {
            super(name);
        }

        public NotFoundException(String name, Exception cause) {
            super(name, cause);
        }
    }

    /**
     * Create a new Resources object on top of an existing set of assets in an
     * AssetManager.
     *
     * @param assets Previously created AssetManager.
     * @param metrics Current display metrics to consider when
     *                selecting/computing resource values.
     * @param config Desired device configuration to consider when
     *               selecting/computing resource values (optional).
     */
    public Resources(AssetManager assets, DisplayMetrics metrics, Configuration config) {
        this(assets, metrics, config, CompatibilityInfo.DEFAULT_COMPATIBILITY_INFO, null);
    }

    /**
     * Creates a new Resources object with CompatibilityInfo.
     *
     * @param assets Previously created AssetManager.
     * @param metrics Current display metrics to consider when
     *                selecting/computing resource values.
     * @param config Desired device configuration to consider when
     *               selecting/computing resource values (optional).
     * @param compatInfo this resource's compatibility info. Must not be null.
     * @param classLoader class loader for the package used to load custom
     *                    resource classes, may be {@code null} to use system
     *                    class loader
     * @hide
     */
    public Resources(AssetManager assets, DisplayMetrics metrics, Configuration config,
            CompatibilityInfo compatInfo, @Nullable ClassLoader classLoader) {
        mAssets = assets;
        mClassLoader = classLoader == null ? ClassLoader.getSystemClassLoader() : classLoader;
        mMetrics.setToDefaults();
        if (compatInfo != null) {
            mCompatibilityInfo = compatInfo;
        }
        updateConfiguration(config, metrics);
        assets.ensureStringBlocks();
    }

    /**
     * Return a global shared Resources object that provides access to only
     * system resources (no application resources), and is not configured for
     * the current screen (can not use dimension units, does not change based
     * on orientation, etc).
     */
    public static Resources getSystem() {
        synchronized (sSync) {
            Resources ret = mSystem;
            if (ret == null) {
                ret = new Resources();
                mSystem = ret;
            }

            return ret;
        }
    }

    /**
     * Return the string value associated with a particular resource ID.  The
     * returned object will be a String if this is a plain string; it will be
     * some other type of CharSequence if it is styled.
     * {@more}
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return CharSequence The string data associated with the resource, plus
     *         possibly styled text information.
     */
    public CharSequence getText(@StringRes int id) throws NotFoundException {
        CharSequence res = mAssets.getResourceText(id);
        if (res != null) {
            return res;
        }
        throw new NotFoundException("String resource ID #0x"
                                    + Integer.toHexString(id));
    }

    /**
     * Returns the character sequence necessary for grammatically correct pluralization
     * of the given resource ID for the given quantity.
     * Note that the character sequence is selected based solely on grammatical necessity,
     * and that such rules differ between languages. Do not assume you know which string
     * will be returned for a given quantity. See
     * <a href="{@docRoot}guide/topics/resources/string-resource.html#Plurals">String Resources</a>
     * for more detail.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     * @param quantity The number used to get the correct string for the current language's
     *           plural rules.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return CharSequence The string data associated with the resource, plus
     *         possibly styled text information.
     */
    public CharSequence getQuantityText(@PluralsRes int id, int quantity)
            throws NotFoundException {
        PluralRules rule = getPluralRule();
        CharSequence res = mAssets.getResourceBagText(id,
                attrForQuantityCode(rule.select(quantity)));
        if (res != null) {
            return res;
        }
        res = mAssets.getResourceBagText(id, ID_OTHER);
        if (res != null) {
            return res;
        }
        throw new NotFoundException("Plural resource ID #0x" + Integer.toHexString(id)
                + " quantity=" + quantity
                + " item=" + rule.select(quantity));
    }

    private PluralRules getPluralRule() {
        synchronized (sSync) {
            if (mPluralRule == null) {
                mPluralRule = PluralRules.forLocale(mConfiguration.getLocales().get(0));
            }
            return mPluralRule;
        }
    }

    private static int attrForQuantityCode(String quantityCode) {
        switch (quantityCode) {
            case PluralRules.KEYWORD_ZERO: return 0x01000005;
            case PluralRules.KEYWORD_ONE:  return 0x01000006;
            case PluralRules.KEYWORD_TWO:  return 0x01000007;
            case PluralRules.KEYWORD_FEW:  return 0x01000008;
            case PluralRules.KEYWORD_MANY: return 0x01000009;
            default:                     return ID_OTHER;
        }
    }

    /**
     * Return the string value associated with a particular resource ID.  It
     * will be stripped of any styled text information.
     * {@more}
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return String The string data associated with the resource,
     *         stripped of styled text information.
     */
    @NonNull
    public String getString(@StringRes int id) throws NotFoundException {
        final CharSequence res = getText(id);
        if (res != null) {
            return res.toString();
        }
        throw new NotFoundException("String resource ID #0x"
                                    + Integer.toHexString(id));
    }


    /**
     * Return the string value associated with a particular resource ID,
     * substituting the format arguments as defined in {@link java.util.Formatter}
     * and {@link java.lang.String#format}. It will be stripped of any styled text
     * information.
     * {@more}
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @param formatArgs The format arguments that will be used for substitution.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return String The string data associated with the resource,
     *         stripped of styled text information.
     */
    @NonNull
    public String getString(@StringRes int id, Object... formatArgs) throws NotFoundException {
        final String raw = getString(id);
        return String.format(mConfiguration.getLocales().get(0), raw, formatArgs);
    }

    /**
     * Formats the string necessary for grammatically correct pluralization
     * of the given resource ID for the given quantity, using the given arguments.
     * Note that the string is selected based solely on grammatical necessity,
     * and that such rules differ between languages. Do not assume you know which string
     * will be returned for a given quantity. See
     * <a href="{@docRoot}guide/topics/resources/string-resource.html#Plurals">String Resources</a>
     * for more detail.
     *
     * <p>Substitution of format arguments works as if using
     * {@link java.util.Formatter} and {@link java.lang.String#format}.
     * The resulting string will be stripped of any styled text information.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     * @param quantity The number used to get the correct string for the current language's
     *           plural rules.
     * @param formatArgs The format arguments that will be used for substitution.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return String The string data associated with the resource,
     * stripped of styled text information.
     */
    public String getQuantityString(@PluralsRes int id, int quantity, Object... formatArgs)
            throws NotFoundException {
        String raw = getQuantityText(id, quantity).toString();
        return String.format(mConfiguration.getLocales().get(0), raw, formatArgs);
    }

    /**
     * Returns the string necessary for grammatically correct pluralization
     * of the given resource ID for the given quantity.
     * Note that the string is selected based solely on grammatical necessity,
     * and that such rules differ between languages. Do not assume you know which string
     * will be returned for a given quantity. See
     * <a href="{@docRoot}guide/topics/resources/string-resource.html#Plurals">String Resources</a>
     * for more detail.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     * @param quantity The number used to get the correct string for the current language's
     *           plural rules.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return String The string data associated with the resource,
     * stripped of styled text information.
     */
    public String getQuantityString(@PluralsRes int id, int quantity)
            throws NotFoundException {
        return getQuantityText(id, quantity).toString();
    }

    /**
     * Return the string value associated with a particular resource ID.  The
     * returned object will be a String if this is a plain string; it will be
     * some other type of CharSequence if it is styled.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @param def The default CharSequence to return.
     *
     * @return CharSequence The string data associated with the resource, plus
     *         possibly styled text information, or def if id is 0 or not found.
     */
    public CharSequence getText(@StringRes int id, CharSequence def) {
        CharSequence res = id != 0 ? mAssets.getResourceText(id) : null;
        return res != null ? res : def;
    }

    /**
     * Return the styled text array associated with a particular resource ID.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return The styled text array associated with the resource.
     */
    public CharSequence[] getTextArray(@ArrayRes int id) throws NotFoundException {
        CharSequence[] res = mAssets.getResourceTextArray(id);
        if (res != null) {
            return res;
        }
        throw new NotFoundException("Text array resource ID #0x"
                                    + Integer.toHexString(id));
    }

    /**
     * Return the string array associated with a particular resource ID.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return The string array associated with the resource.
     */
    public String[] getStringArray(@ArrayRes int id)
            throws NotFoundException {
        String[] res = mAssets.getResourceStringArray(id);
        if (res != null) {
            return res;
        }
        throw new NotFoundException("String array resource ID #0x"
                                    + Integer.toHexString(id));
    }

    /**
     * Return the int array associated with a particular resource ID.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return The int array associated with the resource.
     */
    public int[] getIntArray(@ArrayRes int id) throws NotFoundException {
        int[] res = mAssets.getArrayIntResource(id);
        if (res != null) {
            return res;
        }
        throw new NotFoundException("Int array resource ID #0x"
                                    + Integer.toHexString(id));
    }

    /**
     * Return an array of heterogeneous values.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return Returns a TypedArray holding an array of the array values.
     * Be sure to call {@link TypedArray#recycle() TypedArray.recycle()}
     * when done with it.
     */
    public TypedArray obtainTypedArray(@ArrayRes int id)
            throws NotFoundException {
        int len = mAssets.getArraySize(id);
        if (len < 0) {
            throw new NotFoundException("Array resource ID #0x"
                                        + Integer.toHexString(id));
        }

        TypedArray array = TypedArray.obtain(this, len);
        array.mLength = mAssets.retrieveArray(id, array.mData);
        array.mIndices[0] = 0;

        return array;
    }

    /**
     * Retrieve a dimensional for a particular resource ID.  Unit
     * conversions are based on the current {@link DisplayMetrics} associated
     * with the resources.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @return Resource dimension value multiplied by the appropriate
     * metric.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @see #getDimensionPixelOffset
     * @see #getDimensionPixelSize
     */
    public float getDimension(@DimenRes int id) throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            if (value.type == TypedValue.TYPE_DIMENSION) {
                return TypedValue.complexToDimension(value.data, mMetrics);
            }
            throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
                    + " type #0x" + Integer.toHexString(value.type) + " is not valid");
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Retrieve a dimensional for a particular resource ID for use
     * as an offset in raw pixels.  This is the same as
     * {@link #getDimension}, except the returned value is converted to
     * integer pixels for you.  An offset conversion involves simply
     * truncating the base value to an integer.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @return Resource dimension value multiplied by the appropriate
     * metric and truncated to integer pixels.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @see #getDimension
     * @see #getDimensionPixelSize
     */
    public int getDimensionPixelOffset(@DimenRes int id) throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            if (value.type == TypedValue.TYPE_DIMENSION) {
                return TypedValue.complexToDimensionPixelOffset(value.data, mMetrics);
            }
            throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
                    + " type #0x" + Integer.toHexString(value.type) + " is not valid");
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Retrieve a dimensional for a particular resource ID for use
     * as a size in raw pixels.  This is the same as
     * {@link #getDimension}, except the returned value is converted to
     * integer pixels for use as a size.  A size conversion involves
     * rounding the base value, and ensuring that a non-zero base value
     * is at least one pixel in size.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @return Resource dimension value multiplied by the appropriate
     * metric and truncated to integer pixels.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @see #getDimension
     * @see #getDimensionPixelOffset
     */
    public int getDimensionPixelSize(@DimenRes int id) throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            if (value.type == TypedValue.TYPE_DIMENSION) {
                return TypedValue.complexToDimensionPixelSize(value.data, mMetrics);
            }
            throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
                    + " type #0x" + Integer.toHexString(value.type) + " is not valid");
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Retrieve a fractional unit for a particular resource ID.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     * @param base The base value of this fraction.  In other words, a
     *             standard fraction is multiplied by this value.
     * @param pbase The parent base value of this fraction.  In other
     *             words, a parent fraction (nn%p) is multiplied by this
     *             value.
     *
     * @return Attribute fractional value multiplied by the appropriate
     * base value.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     */
    public float getFraction(@FractionRes int id, int base, int pbase) {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            if (value.type == TypedValue.TYPE_FRACTION) {
                return TypedValue.complexToFraction(value.data, base, pbase);
            }
            throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
                    + " type #0x" + Integer.toHexString(value.type) + " is not valid");
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Return a drawable object associated with a particular resource ID.
     * Various types of objects will be returned depending on the underlying
     * resource -- for example, a solid color, PNG image, scalable image, etc.
     * The Drawable API hides these implementation details.
     *
     * <p class="note"><strong>Note:</strong> Prior to
     * {@link android.os.Build.VERSION_CODES#JELLY_BEAN}, this function
     * would not correctly retrieve the final configuration density when
     * the resource ID passed here is an alias to another Drawable resource.
     * This means that if the density configuration of the alias resource
     * is different than the actual resource, the density of the returned
     * Drawable would be incorrect, resulting in bad scaling.  To work
     * around this, you can instead retrieve the Drawable through
     * {@link TypedArray#getDrawable TypedArray.getDrawable}.  Use
     * {@link android.content.Context#obtainStyledAttributes(int[])
     * Context.obtainStyledAttributes} with
     * an array containing the resource ID of interest to create the TypedArray.</p>
     *
     * <p class="note"><strong>Note:</strong> To obtain a themed drawable, use
     * {@link android.content.Context#getDrawable(int) Context.getDrawable(int)}
     * or {@link #getDrawable(int, Theme)} passing the desired theme.</p>
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     * @return Drawable An object that can be used to draw this resource.
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *         not exist.
     * @see #getDrawable(int, Theme)
     * @deprecated Use {@link #getDrawable(int, Theme)} instead.
     */
    @Deprecated
    public Drawable getDrawable(@DrawableRes int id) throws NotFoundException {
        final Drawable d = getDrawable(id, null);
        if (d != null && d.canApplyTheme()) {
            Log.w(TAG, "Drawable " + getResourceName(id) + " has unresolved theme "
                    + "attributes! Consider using Resources.getDrawable(int, Theme) or "
                    + "Context.getDrawable(int).", new RuntimeException());
        }
        return d;
    }

    /**
     * Return a drawable object associated with a particular resource ID and
     * styled for the specified theme. Various types of objects will be
     * returned depending on the underlying resource -- for example, a solid
     * color, PNG image, scalable image, etc.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     * @param theme The theme used to style the drawable attributes, may be {@code null}.
     * @return Drawable An object that can be used to draw this resource.
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *         not exist.
     */
    public Drawable getDrawable(@DrawableRes int id, @Nullable Theme theme)
            throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            return loadDrawable(value, id, theme);
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Return a drawable object associated with a particular resource ID for the
     * given screen density in DPI. This will set the drawable's density to be
     * the device's density multiplied by the ratio of actual drawable density
     * to requested density. This allows the drawable to be scaled up to the
     * correct size if needed. Various types of objects will be returned
     * depending on the underlying resource -- for example, a solid color, PNG
     * image, scalable image, etc. The Drawable API hides these implementation
     * details.
     *
     * <p class="note"><strong>Note:</strong> To obtain a themed drawable, use
     * {@link android.content.Context#getDrawable(int) Context.getDrawable(int)}
     * or {@link #getDrawableForDensity(int, int, Theme)} passing the desired
     * theme.</p>
     *
     * @param id The desired resource identifier, as generated by the aapt tool.
     *            This integer encodes the package, type, and resource entry.
     *            The value 0 is an invalid identifier.
     * @param density the desired screen density indicated by the resource as
     *            found in {@link DisplayMetrics}.
     * @return Drawable An object that can be used to draw this resource.
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *             not exist.
     * @see #getDrawableForDensity(int, int, Theme)
     * @deprecated Use {@link #getDrawableForDensity(int, int, Theme)} instead.
     */
    @Deprecated
    public Drawable getDrawableForDensity(@DrawableRes int id, int density)
            throws NotFoundException {
        return getDrawableForDensity(id, density, null);
    }

    /**
     * Return a drawable object associated with a particular resource ID for the
     * given screen density in DPI and styled for the specified theme.
     *
     * @param id The desired resource identifier, as generated by the aapt tool.
     *            This integer encodes the package, type, and resource entry.
     *            The value 0 is an invalid identifier.
     * @param density The desired screen density indicated by the resource as
     *            found in {@link DisplayMetrics}.
     * @param theme The theme used to style the drawable attributes, may be {@code null}.
     * @return Drawable An object that can be used to draw this resource.
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *             not exist.
     */
    public Drawable getDrawableForDensity(@DrawableRes int id, int density, @Nullable Theme theme) {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            getValueForDensity(id, density, value, true);

            // If the drawable's XML lives in our current density qualifier,
            // it's okay to use a scaled version from the cache. Otherwise, we
            // need to actually load the drawable from XML.
            final boolean useCache = value.density == mMetrics.densityDpi;

            /*
             * Pretend the requested density is actually the display density. If
             * the drawable returned is not the requested density, then force it
             * to be scaled later by dividing its density by the ratio of
             * requested density to actual device density. Drawables that have
             * undefined density or no density don't need to be handled here.
             */
            if (value.density > 0 && value.density != TypedValue.DENSITY_NONE) {
                if (value.density == density) {
                    value.density = mMetrics.densityDpi;
                } else {
                    value.density = (value.density * mMetrics.densityDpi) / density;
                }
            }

            return loadDrawable(value, id, theme, useCache);
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Return a movie object associated with the particular resource ID.
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     */
    public Movie getMovie(@RawRes int id) throws NotFoundException {
        InputStream is = openRawResource(id);
        Movie movie = Movie.decodeStream(is);
        try {
            is.close();
        }
        catch (java.io.IOException e) {
            // don't care, since the return value is valid
        }
        return movie;
    }

    /**
     * Returns a color integer associated with a particular resource ID. If the
     * resource holds a complex {@link ColorStateList}, then the default color
     * from the set is returned.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *         not exist.
     *
     * @return A single color value in the form 0xAARRGGBB.
     * @deprecated Use {@link #getColor(int, Theme)} instead.
     */
    @ColorInt
    @Deprecated
    public int getColor(@ColorRes int id) throws NotFoundException {
        return getColor(id, null);
    }

    /**
     * Returns a themed color integer associated with a particular resource ID.
     * If the resource holds a complex {@link ColorStateList}, then the default
     * color from the set is returned.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     * @param theme The theme used to style the color attributes, may be
     *              {@code null}.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *         not exist.
     *
     * @return A single color value in the form 0xAARRGGBB.
     */
    @ColorInt
    public int getColor(@ColorRes int id, @Nullable Theme theme) throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            if (value.type >= TypedValue.TYPE_FIRST_INT
                    && value.type <= TypedValue.TYPE_LAST_INT) {
                return value.data;
            } else if (value.type != TypedValue.TYPE_STRING) {
                throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
                        + " type #0x" + Integer.toHexString(value.type) + " is not valid");
            }

            final ColorStateList csl = loadColorStateList(value, id, theme);
            return csl.getDefaultColor();
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Returns a color state list associated with a particular resource ID. The
     * resource may contain either a single raw color value or a complex
     * {@link ColorStateList} holding multiple possible colors.
     *
     * @param id The desired resource identifier of a {@link ColorStateList},
     *           as generated by the aapt tool. This integer encodes the
     *           package, type, and resource entry. The value 0 is an invalid
     *           identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *         not exist.
     *
     * @return A ColorStateList object containing either a single solid color
     *         or multiple colors that can be selected based on a state.
     * @deprecated Use {@link #getColorStateList(int, Theme)} instead.
     */
    @Nullable
    @Deprecated
    public ColorStateList getColorStateList(@ColorRes int id) throws NotFoundException {
        final ColorStateList csl = getColorStateList(id, null);
        if (csl != null && csl.canApplyTheme()) {
            Log.w(TAG, "ColorStateList " + getResourceName(id) + " has "
                    + "unresolved theme attributes! Consider using "
                    + "Resources.getColorStateList(int, Theme) or "
                    + "Context.getColorStateList(int).", new RuntimeException());
        }
        return csl;
    }

    /**
     * Returns a themed color state list associated with a particular resource
     * ID. The resource may contain either a single raw color value or a
     * complex {@link ColorStateList} holding multiple possible colors.
     *
     * @param id The desired resource identifier of a {@link ColorStateList},
     *           as generated by the aapt tool. This integer encodes the
     *           package, type, and resource entry. The value 0 is an invalid
     *           identifier.
     * @param theme The theme used to style the color attributes, may be
     *              {@code null}.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *         not exist.
     *
     * @return A themed ColorStateList object containing either a single solid
     *         color or multiple colors that can be selected based on a state.
     */
    @Nullable
    public ColorStateList getColorStateList(@ColorRes int id, @Nullable Theme theme)
            throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            return loadColorStateList(value, id, theme);
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Return a boolean associated with a particular resource ID.  This can be
     * used with any integral resource value, and will return true if it is
     * non-zero.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return Returns the boolean value contained in the resource.
     */
    public boolean getBoolean(@BoolRes int id) throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            if (value.type >= TypedValue.TYPE_FIRST_INT
                    && value.type <= TypedValue.TYPE_LAST_INT) {
                return value.data != 0;
            }
            throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
                    + " type #0x" + Integer.toHexString(value.type) + " is not valid");
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Return an integer associated with a particular resource ID.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return Returns the integer value contained in the resource.
     */
    public int getInteger(@IntegerRes int id) throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            if (value.type >= TypedValue.TYPE_FIRST_INT
                    && value.type <= TypedValue.TYPE_LAST_INT) {
                return value.data;
            }
            throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
                    + " type #0x" + Integer.toHexString(value.type) + " is not valid");
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Retrieve a floating-point value for a particular resource ID.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @return Returns the floating-point value contained in the resource.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *         not exist or is not a floating-point value.
     * @hide Pending API council approval.
     */
    public float getFloat(int id) {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            if (value.type == TypedValue.TYPE_FLOAT) {
                return value.getFloat();
            }
            throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
                    + " type #0x" + Integer.toHexString(value.type) + " is not valid");
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Return an XmlResourceParser through which you can read a view layout
     * description for the given resource ID.  This parser has limited
     * functionality -- in particular, you can't change its input, and only
     * the high-level events are available.
     *
     * <p>This function is really a simple wrapper for calling
     * {@link #getXml} with a layout resource.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return A new parser object through which you can read
     *         the XML data.
     *
     * @see #getXml
     */
    public XmlResourceParser getLayout(@LayoutRes int id) throws NotFoundException {
        return loadXmlResourceParser(id, "layout");
    }

    /**
     * Return an XmlResourceParser through which you can read an animation
     * description for the given resource ID.  This parser has limited
     * functionality -- in particular, you can't change its input, and only
     * the high-level events are available.
     *
     * <p>This function is really a simple wrapper for calling
     * {@link #getXml} with an animation resource.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return A new parser object through which you can read
     *         the XML data.
     *
     * @see #getXml
     */
    public XmlResourceParser getAnimation(@AnimRes int id) throws NotFoundException {
        return loadXmlResourceParser(id, "anim");
    }

    /**
     * Return an XmlResourceParser through which you can read a generic XML
     * resource for the given resource ID.
     *
     * <p>The XmlPullParser implementation returned here has some limited
     * functionality.  In particular, you can't change its input, and only
     * high-level parsing events are available (since the document was
     * pre-parsed for you at build time, which involved merging text and
     * stripping comments).
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @return A new parser object through which you can read
     *         the XML data.
     *
     * @see android.util.AttributeSet
     */
    public XmlResourceParser getXml(@XmlRes int id) throws NotFoundException {
        return loadXmlResourceParser(id, "xml");
    }

    /**
     * Open a data stream for reading a raw resource.  This can only be used
     * with resources whose value is the name of an asset files -- that is, it can be
     * used to open drawable, sound, and raw resources; it will fail on string
     * and color resources.
     *
     * @param id The resource identifier to open, as generated by the appt
     *           tool.
     *
     * @return InputStream Access to the resource data.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     */
    public InputStream openRawResource(@RawRes int id) throws NotFoundException {
        final TypedValue value = obtainTempTypedValue();
        try {
            return openRawResource(id, value);
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Returns a TypedValue populated with data for the specified resource ID
     * that's suitable for temporary use. The obtained TypedValue should be
     * released using {@link #releaseTempTypedValue(TypedValue)}.
     *
     * @param id the resource ID for which data should be obtained
     * @return a populated typed value suitable for temporary use
     */
    private TypedValue obtainTempTypedValue(@AnyRes int id) {
        final TypedValue value = obtainTempTypedValue();
        getValue(id, value, true);
        return value;
    }

    /**
     * Returns a TypedValue suitable for temporary use. The obtained TypedValue
     * should be released using {@link #releaseTempTypedValue(TypedValue)}.
     *
     * @return a typed value suitable for temporary use
     */
    private TypedValue obtainTempTypedValue() {
        TypedValue tmpValue = null;
        synchronized (mTmpValueLock) {
            if (mTmpValue != null) {
                tmpValue = mTmpValue;
                mTmpValue = null;
            }
        }
        if (tmpValue == null) {
            return new TypedValue();
        }
        return tmpValue;
    }

    /**
     * Returns a TypedValue to the pool. After calling this method, the
     * specified TypedValue should no longer be accessed.
     *
     * @param value the typed value to return to the pool
     */
    private void releaseTempTypedValue(TypedValue value) {
        synchronized (mTmpValueLock) {
            if (mTmpValue == null) {
                mTmpValue = value;
            }
        }
    }

    /**
     * Open a data stream for reading a raw resource.  This can only be used
     * with resources whose value is the name of an asset file -- that is, it can be
     * used to open drawable, sound, and raw resources; it will fail on string
     * and color resources.
     *
     * @param id The resource identifier to open, as generated by the appt tool.
     * @param value The TypedValue object to hold the resource information.
     *
     * @return InputStream Access to the resource data.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     */
    public InputStream openRawResource(@RawRes int id, TypedValue value)
            throws NotFoundException {
        getValue(id, value, true);

        try {
            return mAssets.openNonAsset(value.assetCookie, value.string.toString(),
                    AssetManager.ACCESS_STREAMING);
        } catch (Exception e) {
            NotFoundException rnf = new NotFoundException("File " + value.string.toString() +
                    " from drawable resource ID #0x" + Integer.toHexString(id));
            rnf.initCause(e);
            throw rnf;
        }
    }

    /**
     * Open a file descriptor for reading a raw resource.  This can only be used
     * with resources whose value is the name of an asset files -- that is, it can be
     * used to open drawable, sound, and raw resources; it will fail on string
     * and color resources.
     *
     * <p>This function only works for resources that are stored in the package
     * as uncompressed data, which typically includes things like mp3 files
     * and png images.
     *
     * @param id The resource identifier to open, as generated by the appt
     *           tool.
     *
     * @return AssetFileDescriptor A new file descriptor you can use to read
     * the resource.  This includes the file descriptor itself, as well as the
     * offset and length of data where the resource appears in the file.  A
     * null is returned if the file exists but is compressed.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     */
    public AssetFileDescriptor openRawResourceFd(@RawRes int id)
            throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            return mAssets.openNonAssetFd(value.assetCookie, value.string.toString());
        } catch (Exception e) {
            throw new NotFoundException("File " + value.string.toString() + " from drawable "
                    + "resource ID #0x" + Integer.toHexString(id), e);
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Return the raw data associated with a particular resource ID.
     *
     * @param id The desired resource identifier, as generated by the aapt
     *           tool. This integer encodes the package, type, and resource
     *           entry. The value 0 is an invalid identifier.
     * @param outValue Object in which to place the resource data.
     * @param resolveRefs If true, a resource that is a reference to another
     *                    resource will be followed so that you receive the
     *                    actual final resource data.  If false, the TypedValue
     *                    will be filled in with the reference itself.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     */
    public void getValue(@AnyRes int id, TypedValue outValue, boolean resolveRefs)
            throws NotFoundException {
        boolean found = mAssets.getResourceValue(id, 0, outValue, resolveRefs);
        if (found) {
            return;
        }
        throw new NotFoundException("Resource ID #0x"
                                    + Integer.toHexString(id));
    }

    /**
     * Get the raw value associated with a resource with associated density.
     *
     * @param id resource identifier
     * @param density density in DPI
     * @param resolveRefs If true, a resource that is a reference to another
     *            resource will be followed so that you receive the actual final
     *            resource data. If false, the TypedValue will be filled in with
     *            the reference itself.
     * @throws NotFoundException Throws NotFoundException if the given ID does
     *             not exist.
     * @see #getValue(String, TypedValue, boolean)
     */
    public void getValueForDensity(@AnyRes int id, int density, TypedValue outValue,
            boolean resolveRefs) throws NotFoundException {
        boolean found = mAssets.getResourceValue(id, density, outValue, resolveRefs);
        if (found) {
            return;
        }
        throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id));
    }

    /**
     * Return the raw data associated with a particular resource ID.
     * See getIdentifier() for information on how names are mapped to resource
     * IDs, and getString(int) for information on how string resources are
     * retrieved.
     *
     * <p>Note: use of this function is discouraged.  It is much more
     * efficient to retrieve resources by identifier than by name.
     *
     * @param name The name of the desired resource.  This is passed to
     *             getIdentifier() with a default type of "string".
     * @param outValue Object in which to place the resource data.
     * @param resolveRefs If true, a resource that is a reference to another
     *                    resource will be followed so that you receive the
     *                    actual final resource data.  If false, the TypedValue
     *                    will be filled in with the reference itself.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     */
    public void getValue(String name, TypedValue outValue, boolean resolveRefs)
            throws NotFoundException {
        int id = getIdentifier(name, "string", null);
        if (id != 0) {
            getValue(id, outValue, resolveRefs);
            return;
        }
        throw new NotFoundException("String resource name " + name);
    }

    /**
     * This class holds the current attribute values for a particular theme.
     * In other words, a Theme is a set of values for resource attributes;
     * these are used in conjunction with {@link TypedArray}
     * to resolve the final value for an attribute.
     *
     * <p>The Theme's attributes come into play in two ways: (1) a styled
     * attribute can explicit reference a value in the theme through the
     * "?themeAttribute" syntax; (2) if no value has been defined for a
     * particular styled attribute, as a last resort we will try to find that
     * attribute's value in the Theme.
     *
     * <p>You will normally use the {@link #obtainStyledAttributes} APIs to
     * retrieve XML attributes with style and theme information applied.
     */
    public final class Theme {
        /**
         * Place new attribute values into the theme.  The style resource
         * specified by <var>resid</var> will be retrieved from this Theme's
         * resources, its values placed into the Theme object.
         *
         * <p>The semantics of this function depends on the <var>force</var>
         * argument:  If false, only values that are not already defined in
         * the theme will be copied from the system resource; otherwise, if
         * any of the style's attributes are already defined in the theme, the
         * current values in the theme will be overwritten.
         *
         * @param resId The resource ID of a style resource from which to
         *              obtain attribute values.
         * @param force If true, values in the style resource will always be
         *              used in the theme; otherwise, they will only be used
         *              if not already defined in the theme.
         */
        public void applyStyle(int resId, boolean force) {
            synchronized (mKey) {
                AssetManager.applyThemeStyle(mTheme, resId, force);

                mThemeResId = resId;
                mKey.append(resId, force);
            }
        }

        /**
         * Set this theme to hold the same contents as the theme
         * <var>other</var>.  If both of these themes are from the same
         * Resources object, they will be identical after this function
         * returns.  If they are from different Resources, only the resources
         * they have in common will be set in this theme.
         *
         * @param other The existing Theme to copy from.
         */
        public void setTo(Theme other) {
            synchronized (mKey) {
                synchronized (other.mKey) {
                    AssetManager.copyTheme(mTheme, other.mTheme);

                    mThemeResId = other.mThemeResId;
                    mKey.setTo(other.getKey());
                }
            }
        }

        /**
         * Return a TypedArray holding the values defined by
         * <var>Theme</var> which are listed in <var>attrs</var>.
         *
         * <p>Be sure to call {@link TypedArray#recycle() TypedArray.recycle()} when you are done
         * with the array.
         *
         * @param attrs The desired attributes.
         *
         * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
         *
         * @return Returns a TypedArray holding an array of the attribute values.
         * Be sure to call {@link TypedArray#recycle() TypedArray.recycle()}
         * when done with it.
         *
         * @see Resources#obtainAttributes
         * @see #obtainStyledAttributes(int, int[])
         * @see #obtainStyledAttributes(AttributeSet, int[], int, int)
         */
        public TypedArray obtainStyledAttributes(@StyleableRes int[] attrs) {
            synchronized (mKey) {
                final int len = attrs.length;
                final TypedArray array = TypedArray.obtain(Resources.this, len);
                array.mTheme = this;
                AssetManager.applyStyle(mTheme, 0, 0, 0, attrs, array.mData, array.mIndices);
                return array;
            }
        }

        /**
         * Return a TypedArray holding the values defined by the style
         * resource <var>resid</var> which are listed in <var>attrs</var>.
         *
         * <p>Be sure to call {@link TypedArray#recycle() TypedArray.recycle()} when you are done
         * with the array.
         *
         * @param resId The desired style resource.
         * @param attrs The desired attributes in the style.
         *
         * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
         *
         * @return Returns a TypedArray holding an array of the attribute values.
         * Be sure to call {@link TypedArray#recycle() TypedArray.recycle()}
         * when done with it.
         *
         * @see Resources#obtainAttributes
         * @see #obtainStyledAttributes(int[])
         * @see #obtainStyledAttributes(AttributeSet, int[], int, int)
         */
        public TypedArray obtainStyledAttributes(@StyleRes int resId, @StyleableRes int[] attrs)
                throws NotFoundException {
            synchronized (mKey) {
                final int len = attrs.length;
                final TypedArray array = TypedArray.obtain(Resources.this, len);
                array.mTheme = this;
                AssetManager.applyStyle(mTheme, 0, resId, 0, attrs, array.mData, array.mIndices);
                return array;
            }
        }

        /**
         * Return a TypedArray holding the attribute values in
         * <var>set</var>
         * that are listed in <var>attrs</var>.  In addition, if the given
         * AttributeSet specifies a style class (through the "style" attribute),
         * that style will be applied on top of the base attributes it defines.
         *
         * <p>Be sure to call {@link TypedArray#recycle() TypedArray.recycle()} when you are done
         * with the array.
         *
         * <p>When determining the final value of a particular attribute, there
         * are four inputs that come into play:</p>
         *
         * <ol>
         *     <li> Any attribute values in the given AttributeSet.
         *     <li> The style resource specified in the AttributeSet (named
         *     "style").
         *     <li> The default style specified by <var>defStyleAttr</var> and
         *     <var>defStyleRes</var>
         *     <li> The base values in this theme.
         * </ol>
         *
         * <p>Each of these inputs is considered in-order, with the first listed
         * taking precedence over the following ones.  In other words, if in the
         * AttributeSet you have supplied <code>&lt;Button
         * textColor="#ff000000"&gt;</code>, then the button's text will
         * <em>always</em> be black, regardless of what is specified in any of
         * the styles.
         *
         * @param set The base set of attribute values.  May be null.
         * @param attrs The desired attributes to be retrieved.
         * @param defStyleAttr An attribute in the current theme that contains a
         *                     reference to a style resource that supplies
         *                     defaults values for the TypedArray.  Can be
         *                     0 to not look for defaults.
         * @param defStyleRes A resource identifier of a style resource that
         *                    supplies default values for the TypedArray,
         *                    used only if defStyleAttr is 0 or can not be found
         *                    in the theme.  Can be 0 to not look for defaults.
         *
         * @return Returns a TypedArray holding an array of the attribute values.
         * Be sure to call {@link TypedArray#recycle() TypedArray.recycle()}
         * when done with it.
         *
         * @see Resources#obtainAttributes
         * @see #obtainStyledAttributes(int[])
         * @see #obtainStyledAttributes(int, int[])
         */
        public TypedArray obtainStyledAttributes(AttributeSet set,
                @StyleableRes int[] attrs, @AttrRes int defStyleAttr, @StyleRes int defStyleRes) {
            synchronized (mKey) {
                final int len = attrs.length;
                final TypedArray array = TypedArray.obtain(Resources.this, len);

                // XXX note that for now we only work with compiled XML files.
                // To support generic XML files we will need to manually parse
                // out the attributes from the XML file (applying type information
                // contained in the resources and such).
                final XmlBlock.Parser parser = (XmlBlock.Parser) set;
                AssetManager.applyStyle(mTheme, defStyleAttr, defStyleRes,
                        parser != null ? parser.mParseState : 0,
                        attrs, array.mData, array.mIndices);
                array.mTheme = this;
                array.mXml = parser;

                return array;
            }
        }

        /**
         * Retrieve the values for a set of attributes in the Theme. The
         * contents of the typed array are ultimately filled in by
         * {@link Resources#getValue}.
         *
         * @param values The base set of attribute values, must be equal in
         *               length to {@code attrs}. All values must be of type
         *               {@link TypedValue#TYPE_ATTRIBUTE}.
         * @param attrs The desired attributes to be retrieved.
         * @return Returns a TypedArray holding an array of the attribute
         *         values. Be sure to call {@link TypedArray#recycle()}
         *         when done with it.
         * @hide
         */
        @NonNull
        public TypedArray resolveAttributes(@NonNull int[] values, @NonNull int[] attrs) {
            synchronized (mKey) {
                final int len = attrs.length;
                if (values == null || len != values.length) {
                    throw new IllegalArgumentException(
                            "Base attribute values must the same length as attrs");
                }

                final TypedArray array = TypedArray.obtain(Resources.this, len);
                AssetManager.resolveAttrs(mTheme, 0, 0, values, attrs, array.mData, array.mIndices);
                array.mTheme = this;
                array.mXml = null;

                return array;
            }
        }

        /**
         * Retrieve the value of an attribute in the Theme.  The contents of
         * <var>outValue</var> are ultimately filled in by
         * {@link Resources#getValue}.
         *
         * @param resid The resource identifier of the desired theme
         *              attribute.
         * @param outValue Filled in with the ultimate resource value supplied
         *                 by the attribute.
         * @param resolveRefs If true, resource references will be walked; if
         *                    false, <var>outValue</var> may be a
         *                    TYPE_REFERENCE.  In either case, it will never
         *                    be a TYPE_ATTRIBUTE.
         *
         * @return boolean Returns true if the attribute was found and
         *         <var>outValue</var> is valid, else false.
         */
        public boolean resolveAttribute(int resid, TypedValue outValue, boolean resolveRefs) {
            synchronized (mKey) {
                return mAssets.getThemeValue(mTheme, resid, outValue, resolveRefs);
            }
        }

        /**
         * Gets all of the attribute ids associated with this {@link Theme}. For debugging only.
         *
         * @return The int array containing attribute ids associated with this {@link Theme}.
         * @hide
         */
        public int[] getAllAttributes() {
            return mAssets.getStyleAttributes(getAppliedStyleResId());
        }

        /**
         * Returns the resources to which this theme belongs.
         *
         * @return Resources to which this theme belongs.
         */
        public Resources getResources() {
            return Resources.this;
        }

        /**
         * Return a drawable object associated with a particular resource ID
         * and styled for the Theme.
         *
         * @param id The desired resource identifier, as generated by the aapt
         *           tool. This integer encodes the package, type, and resource
         *           entry. The value 0 is an invalid identifier.
         * @return Drawable An object that can be used to draw this resource.
         * @throws NotFoundException Throws NotFoundException if the given ID
         *         does not exist.
         */
        public Drawable getDrawable(@DrawableRes int id) throws NotFoundException {
            return Resources.this.getDrawable(id, this);
        }

        /**
         * Returns a bit mask of configuration changes that will impact this
         * theme (and thus require completely reloading it).
         *
         * @return a bit mask of configuration changes, as defined by
         *         {@link ActivityInfo}
         * @see ActivityInfo
         */
        public int getChangingConfigurations() {
            synchronized (mKey) {
                final int nativeChangingConfig =
                        AssetManager.getThemeChangingConfigurations(mTheme);
                return ActivityInfo.activityInfoConfigNativeToJava(nativeChangingConfig);
            }
        }

        /**
         * Print contents of this theme out to the log.  For debugging only.
         *
         * @param priority The log priority to use.
         * @param tag The log tag to use.
         * @param prefix Text to prefix each line printed.
         */
        public void dump(int priority, String tag, String prefix) {
            synchronized (mKey) {
                AssetManager.dumpTheme(mTheme, priority, tag, prefix);
            }
        }

        @Override
        protected void finalize() throws Throwable {
            super.finalize();
            mAssets.releaseTheme(mTheme);
        }

        /*package*/ Theme() {
            mAssets = Resources.this.mAssets;
            mTheme = mAssets.createTheme();
        }

        /** Unique key for the series of styles applied to this theme. */
        private final ThemeKey mKey = new ThemeKey();

        @SuppressWarnings("hiding")
        private final AssetManager mAssets;
        private final long mTheme;

        /** Resource identifier for the theme. */
        private int mThemeResId = 0;

        // Needed by layoutlib.
        /*package*/ long getNativeTheme() {
            return mTheme;
        }

        /*package*/ int getAppliedStyleResId() {
            return mThemeResId;
        }

        /*package*/ ThemeKey getKey() {
            return mKey;
        }

        private String getResourceNameFromHexString(String hexString) {
            return getResourceName(Integer.parseInt(hexString, 16));
        }

        /**
         * Parses {@link #mKey} and returns a String array that holds pairs of
         * adjacent Theme data: resource name followed by whether or not it was
         * forced, as specified by {@link #applyStyle(int, boolean)}.
         *
         * @hide
         */
        @ViewDebug.ExportedProperty(category = "theme", hasAdjacentMapping = true)
        public String[] getTheme() {
            synchronized (mKey) {
                final int N = mKey.mCount;
                final String[] themes = new String[N * 2];
                for (int i = 0, j = N - 1; i < themes.length; i += 2, --j) {
                    final int resId = mKey.mResId[j];
                    final boolean forced = mKey.mForce[j];
                    try {
                        themes[i] = getResourceName(resId);
                    } catch (NotFoundException e) {
                        themes[i] = Integer.toHexString(i);
                    }
                    themes[i + 1] = forced ? "forced" : "not forced";
                }
                return themes;
            }
        }

        /** @hide */
        public void encode(@NonNull ViewHierarchyEncoder encoder) {
            encoder.beginObject(this);
            final String[] properties = getTheme();
            for (int i = 0; i < properties.length; i += 2) {
                encoder.addProperty(properties[i], properties[i+1]);
            }
            encoder.endObject();
        }

        /**
         * Rebases the theme against the parent Resource object's current
         * configuration by re-applying the styles passed to
         * {@link #applyStyle(int, boolean)}.
         *
         * @hide
         */
        public void rebase() {
            synchronized (mKey) {
                AssetManager.clearTheme(mTheme);

                // Reapply the same styles in the same order.
                for (int i = 0; i < mKey.mCount; i++) {
                    final int resId = mKey.mResId[i];
                    final boolean force = mKey.mForce[i];
                    AssetManager.applyThemeStyle(mTheme, resId, force);
                }
            }
        }
    }

    static class ThemeKey implements Cloneable {
        int[] mResId;
        boolean[] mForce;
        int mCount;

        private int mHashCode = 0;

        public void append(int resId, boolean force) {
            if (mResId == null) {
                mResId = new int[4];
            }

            if (mForce == null) {
                mForce = new boolean[4];
            }

            mResId = GrowingArrayUtils.append(mResId, mCount, resId);
            mForce = GrowingArrayUtils.append(mForce, mCount, force);
            mCount++;

            mHashCode = 31 * (31 * mHashCode + resId) + (force ? 1 : 0);
        }

        /**
         * Sets up this key as a deep copy of another key.
         *
         * @param other the key to deep copy into this key
         */
        public void setTo(ThemeKey other) {
            mResId = other.mResId == null ? null : other.mResId.clone();
            mForce = other.mForce == null ? null : other.mForce.clone();
            mCount = other.mCount;
        }

        @Override
        public int hashCode() {
            return mHashCode;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) {
                return true;
            }

            if (o == null || getClass() != o.getClass() || hashCode() != o.hashCode()) {
                return false;
            }

            final ThemeKey t = (ThemeKey) o;
            if (mCount != t.mCount) {
                return false;
            }

            final int N = mCount;
            for (int i = 0; i < N; i++) {
                if (mResId[i] != t.mResId[i] || mForce[i] != t.mForce[i]) {
                    return false;
                }
            }

            return true;
        }

        /**
         * @return a shallow copy of this key
         */
        @Override
        public ThemeKey clone() {
            final ThemeKey other = new ThemeKey();
            other.mResId = mResId;
            other.mForce = mForce;
            other.mCount = mCount;
            other.mHashCode = mHashCode;
            return other;
        }
    }

    /**
     * Generate a new Theme object for this set of Resources.  It initially
     * starts out empty.
     *
     * @return Theme The newly created Theme container.
     */
    public final Theme newTheme() {
        return new Theme();
    }

    /**
     * Retrieve a set of basic attribute values from an AttributeSet, not
     * performing styling of them using a theme and/or style resources.
     *
     * @param set The current attribute values to retrieve.
     * @param attrs The specific attributes to be retrieved.
     * @return Returns a TypedArray holding an array of the attribute values.
     * Be sure to call {@link TypedArray#recycle() TypedArray.recycle()}
     * when done with it.
     *
     * @see Theme#obtainStyledAttributes(AttributeSet, int[], int, int)
     */
    public TypedArray obtainAttributes(AttributeSet set, int[] attrs) {
        int len = attrs.length;
        TypedArray array = TypedArray.obtain(this, len);

        // XXX note that for now we only work with compiled XML files.
        // To support generic XML files we will need to manually parse
        // out the attributes from the XML file (applying type information
        // contained in the resources and such).
        XmlBlock.Parser parser = (XmlBlock.Parser)set;
        mAssets.retrieveAttributes(parser.mParseState, attrs,
                array.mData, array.mIndices);

        array.mXml = parser;

        return array;
    }

    /**
     * Store the newly updated configuration.
     */
    public void updateConfiguration(Configuration config,
            DisplayMetrics metrics) {
        updateConfiguration(config, metrics, null);
    }

    /**
     * @hide
     */
    public void updateConfiguration(Configuration config,
            DisplayMetrics metrics, CompatibilityInfo compat) {
        synchronized (mAccessLock) {
            if (false) {
                Slog.i(TAG, "**** Updating config of " + this + ": old config is "
                        + mConfiguration + " old compat is " + mCompatibilityInfo);
                Slog.i(TAG, "**** Updating config of " + this + ": new config is "
                        + config + " new compat is " + compat);
            }
            if (compat != null) {
                mCompatibilityInfo = compat;
            }
            if (metrics != null) {
                mMetrics.setTo(metrics);
            }
            // NOTE: We should re-arrange this code to create a Display
            // with the CompatibilityInfo that is used everywhere we deal
            // with the display in relation to this app, rather than
            // doing the conversion here.  This impl should be okay because
            // we make sure to return a compatible display in the places
            // where there are public APIs to retrieve the display...  but
            // it would be cleaner and more maintainble to just be
            // consistently dealing with a compatible display everywhere in
            // the framework.
            mCompatibilityInfo.applyToDisplayMetrics(mMetrics);

            final int configChanges = calcConfigChanges(config);

            LocaleList locales = mConfiguration.getLocales();
            if (locales.isEmpty()) {
                locales = LocaleList.getAdjustedDefault();
                mConfiguration.setLocales(locales);
            }
            if (mConfiguration.densityDpi != Configuration.DENSITY_DPI_UNDEFINED) {
                mMetrics.densityDpi = mConfiguration.densityDpi;
                mMetrics.density = mConfiguration.densityDpi * DisplayMetrics.DENSITY_DEFAULT_SCALE;
            }
            mMetrics.scaledDensity = mMetrics.density * mConfiguration.fontScale;

            final int width, height;
            if (mMetrics.widthPixels >= mMetrics.heightPixels) {
                width = mMetrics.widthPixels;
                height = mMetrics.heightPixels;
            } else {
                //noinspection SuspiciousNameCombination
                width = mMetrics.heightPixels;
                //noinspection SuspiciousNameCombination
                height = mMetrics.widthPixels;
            }

            final int keyboardHidden;
            if (mConfiguration.keyboardHidden == Configuration.KEYBOARDHIDDEN_NO
                    && mConfiguration.hardKeyboardHidden == Configuration.HARDKEYBOARDHIDDEN_YES) {
                keyboardHidden = Configuration.KEYBOARDHIDDEN_SOFT;
            } else {
                keyboardHidden = mConfiguration.keyboardHidden;
            }

            mAssets.setConfiguration(mConfiguration.mcc, mConfiguration.mnc,
                    adjustLanguageTag(locales.get(0).toLanguageTag()),
                    mConfiguration.orientation,
                    mConfiguration.touchscreen,
                    mConfiguration.densityDpi, mConfiguration.keyboard,
                    keyboardHidden, mConfiguration.navigation, width, height,
                    mConfiguration.smallestScreenWidthDp,
                    mConfiguration.screenWidthDp, mConfiguration.screenHeightDp,
                    mConfiguration.screenLayout, mConfiguration.uiMode,
                    Build.VERSION.RESOURCES_SDK_INT);

            if (DEBUG_CONFIG) {
                Slog.i(TAG, "**** Updating config of " + this + ": final config is "
                        + mConfiguration + " final compat is " + mCompatibilityInfo);
            }

            mDrawableCache.onConfigurationChange(configChanges);
            mColorDrawableCache.onConfigurationChange(configChanges);
            mComplexColorCache.onConfigurationChange(configChanges);
            mAnimatorCache.onConfigurationChange(configChanges);
            mStateListAnimatorCache.onConfigurationChange(configChanges);

            flushLayoutCache();
        }
        synchronized (sSync) {
            if (mPluralRule != null) {
                mPluralRule = PluralRules.forLocale(mConfiguration.getLocales().get(0));
            }
        }
    }

    /**
     * Called by ConfigurationBoundResourceCacheTest via reflection.
     */
    private int calcConfigChanges(Configuration config) {
        int configChanges = 0xfffffff;
        if (config != null) {
            mTmpConfig.setTo(config);
            int density = config.densityDpi;
            if (density == Configuration.DENSITY_DPI_UNDEFINED) {
                density = mMetrics.noncompatDensityDpi;
            }

            mCompatibilityInfo.applyToConfiguration(density, mTmpConfig);

            if (mTmpConfig.getLocales().isEmpty()) {
                mTmpConfig.setLocales(LocaleList.getDefault());
            }
            configChanges = mConfiguration.updateFrom(mTmpConfig);
            configChanges = ActivityInfo.activityInfoConfigToNative(configChanges);
        }
        return configChanges;
    }

    /**
     * {@code Locale.toLanguageTag} will transform the obsolete (and deprecated)
     * language codes "in", "ji" and "iw" to "id", "yi" and "he" respectively.
     *
     * All released versions of android prior to "L" used the deprecated language
     * tags, so we will need to support them for backwards compatibility.
     *
     * Note that this conversion needs to take place *after* the call to
     * {@code toLanguageTag} because that will convert all the deprecated codes to
     * the new ones, even if they're set manually.
     */
    private static String adjustLanguageTag(String languageTag) {
        final int separator = languageTag.indexOf('-');
        final String language;
        final String remainder;

        if (separator == -1) {
            language = languageTag;
            remainder = "";
        } else {
            language = languageTag.substring(0, separator);
            remainder = languageTag.substring(separator);
        }

        return Locale.adjustLanguageCode(language) + remainder;
    }

    /**
     * Update the system resources configuration if they have previously
     * been initialized.
     *
     * @hide
     */
    public static void updateSystemConfiguration(Configuration config, DisplayMetrics metrics,
            CompatibilityInfo compat) {
        if (mSystem != null) {
            mSystem.updateConfiguration(config, metrics, compat);
            //Log.i(TAG, "Updated system resources " + mSystem
            //        + ": " + mSystem.getConfiguration());
        }
    }

    /**
     * Return the current display metrics that are in effect for this resource
     * object.  The returned object should be treated as read-only.
     *
     * @return The resource's current display metrics.
     */
    public DisplayMetrics getDisplayMetrics() {
        if (DEBUG_CONFIG) Slog.v(TAG, "Returning DisplayMetrics: " + mMetrics.widthPixels
                + "x" + mMetrics.heightPixels + " " + mMetrics.density);
        return mMetrics;
    }

    /**
     * Return the current configuration that is in effect for this resource
     * object.  The returned object should be treated as read-only.
     *
     * @return The resource's current configuration.
     */
    public Configuration getConfiguration() {
        return mConfiguration;
    }

    /** @hide */
    public Configuration[] getSizeConfigurations() {
        return mAssets.getSizeConfigurations();
    };

    /**
     * Return the compatibility mode information for the application.
     * The returned object should be treated as read-only.
     *
     * @return compatibility info.
     * @hide
     */
    public CompatibilityInfo getCompatibilityInfo() {
        return mCompatibilityInfo;
    }

    /**
     * This is just for testing.
     * @hide
     */
    public void setCompatibilityInfo(CompatibilityInfo ci) {
        if (ci != null) {
            mCompatibilityInfo = ci;
            updateConfiguration(mConfiguration, mMetrics);
        }
    }

    /**
     * Return a resource identifier for the given resource name.  A fully
     * qualified resource name is of the form "package:type/entry".  The first
     * two components (package and type) are optional if defType and
     * defPackage, respectively, are specified here.
     *
     * <p>Note: use of this function is discouraged.  It is much more
     * efficient to retrieve resources by identifier than by name.
     *
     * @param name The name of the desired resource.
     * @param defType Optional default resource type to find, if "type/" is
     *                not included in the name.  Can be null to require an
     *                explicit type.
     * @param defPackage Optional default package to find, if "package:" is
     *                   not included in the name.  Can be null to require an
     *                   explicit package.
     *
     * @return int The associated resource identifier.  Returns 0 if no such
     *         resource was found.  (0 is not a valid resource ID.)
     */
    public int getIdentifier(String name, String defType, String defPackage) {
        if (name == null) {
            throw new NullPointerException("name is null");
        }
        try {
            return Integer.parseInt(name);
        } catch (Exception e) {
            // Ignore
        }
        return mAssets.getResourceIdentifier(name, defType, defPackage);
    }

    /**
     * Return true if given resource identifier includes a package.
     *
     * @hide
     */
    public static boolean resourceHasPackage(@AnyRes int resid) {
        return (resid >>> 24) != 0;
    }

    /**
     * Return the full name for a given resource identifier.  This name is
     * a single string of the form "package:type/entry".
     *
     * @param resid The resource identifier whose name is to be retrieved.
     *
     * @return A string holding the name of the resource.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @see #getResourcePackageName
     * @see #getResourceTypeName
     * @see #getResourceEntryName
     */
    public String getResourceName(@AnyRes int resid) throws NotFoundException {
        String str = mAssets.getResourceName(resid);
        if (str != null) return str;
        throw new NotFoundException("Unable to find resource ID #0x"
                + Integer.toHexString(resid));
    }

    /**
     * Return the package name for a given resource identifier.
     *
     * @param resid The resource identifier whose package name is to be
     * retrieved.
     *
     * @return A string holding the package name of the resource.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @see #getResourceName
     */
    public String getResourcePackageName(@AnyRes int resid) throws NotFoundException {
        String str = mAssets.getResourcePackageName(resid);
        if (str != null) return str;
        throw new NotFoundException("Unable to find resource ID #0x"
                + Integer.toHexString(resid));
    }

    /**
     * Return the type name for a given resource identifier.
     *
     * @param resid The resource identifier whose type name is to be
     * retrieved.
     *
     * @return A string holding the type name of the resource.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @see #getResourceName
     */
    public String getResourceTypeName(@AnyRes int resid) throws NotFoundException {
        String str = mAssets.getResourceTypeName(resid);
        if (str != null) return str;
        throw new NotFoundException("Unable to find resource ID #0x"
                + Integer.toHexString(resid));
    }

    /**
     * Return the entry name for a given resource identifier.
     *
     * @param resid The resource identifier whose entry name is to be
     * retrieved.
     *
     * @return A string holding the entry name of the resource.
     *
     * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
     *
     * @see #getResourceName
     */
    public String getResourceEntryName(@AnyRes int resid) throws NotFoundException {
        String str = mAssets.getResourceEntryName(resid);
        if (str != null) return str;
        throw new NotFoundException("Unable to find resource ID #0x"
                + Integer.toHexString(resid));
    }

    /**
     * Parse a series of {@link android.R.styleable#Extra &lt;extra&gt;} tags from
     * an XML file.  You call this when you are at the parent tag of the
     * extra tags, and it will return once all of the child tags have been parsed.
     * This will call {@link #parseBundleExtra} for each extra tag encountered.
     *
     * @param parser The parser from which to retrieve the extras.
     * @param outBundle A Bundle in which to place all parsed extras.
     * @throws XmlPullParserException
     * @throws IOException
     */
    public void parseBundleExtras(XmlResourceParser parser, Bundle outBundle)
            throws XmlPullParserException, IOException {
        int outerDepth = parser.getDepth();
        int type;
        while ((type=parser.next()) != XmlPullParser.END_DOCUMENT
               && (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) {
            if (type == XmlPullParser.END_TAG || type == XmlPullParser.TEXT) {
                continue;
            }

            String nodeName = parser.getName();
            if (nodeName.equals("extra")) {
                parseBundleExtra("extra", parser, outBundle);
                XmlUtils.skipCurrentTag(parser);

            } else {
                XmlUtils.skipCurrentTag(parser);
            }
        }
    }

    /**
     * Parse a name/value pair out of an XML tag holding that data.  The
     * AttributeSet must be holding the data defined by
     * {@link android.R.styleable#Extra}.  The following value types are supported:
     * <ul>
     * <li> {@link TypedValue#TYPE_STRING}:
     * {@link Bundle#putCharSequence Bundle.putCharSequence()}
     * <li> {@link TypedValue#TYPE_INT_BOOLEAN}:
     * {@link Bundle#putCharSequence Bundle.putBoolean()}
     * <li> {@link TypedValue#TYPE_FIRST_INT}-{@link TypedValue#TYPE_LAST_INT}:
     * {@link Bundle#putCharSequence Bundle.putBoolean()}
     * <li> {@link TypedValue#TYPE_FLOAT}:
     * {@link Bundle#putCharSequence Bundle.putFloat()}
     * </ul>
     *
     * @param tagName The name of the tag these attributes come from; this is
     * only used for reporting error messages.
     * @param attrs The attributes from which to retrieve the name/value pair.
     * @param outBundle The Bundle in which to place the parsed value.
     * @throws XmlPullParserException If the attributes are not valid.
     */
    public void parseBundleExtra(String tagName, AttributeSet attrs,
            Bundle outBundle) throws XmlPullParserException {
        TypedArray sa = obtainAttributes(attrs,
                com.android.internal.R.styleable.Extra);

        String name = sa.getString(
                com.android.internal.R.styleable.Extra_name);
        if (name == null) {
            sa.recycle();
            throw new XmlPullParserException("<" + tagName
                    + "> requires an android:name attribute at "
                    + attrs.getPositionDescription());
        }

        TypedValue v = sa.peekValue(
                com.android.internal.R.styleable.Extra_value);
        if (v != null) {
            if (v.type == TypedValue.TYPE_STRING) {
                CharSequence cs = v.coerceToString();
                outBundle.putCharSequence(name, cs);
            } else if (v.type == TypedValue.TYPE_INT_BOOLEAN) {
                outBundle.putBoolean(name, v.data != 0);
            } else if (v.type >= TypedValue.TYPE_FIRST_INT
                    && v.type <= TypedValue.TYPE_LAST_INT) {
                outBundle.putInt(name, v.data);
            } else if (v.type == TypedValue.TYPE_FLOAT) {
                outBundle.putFloat(name, v.getFloat());
            } else {
                sa.recycle();
                throw new XmlPullParserException("<" + tagName
                        + "> only supports string, integer, float, color, and boolean at "
                        + attrs.getPositionDescription());
            }
        } else {
            sa.recycle();
            throw new XmlPullParserException("<" + tagName
                    + "> requires an android:value or android:resource attribute at "
                    + attrs.getPositionDescription());
        }

        sa.recycle();
    }

    /**
     * Retrieve underlying AssetManager storage for these resources.
     */
    public final AssetManager getAssets() {
        return mAssets;
    }

    /**
     * Call this to remove all cached loaded layout resources from the
     * Resources object.  Only intended for use with performance testing
     * tools.
     */
    public final void flushLayoutCache() {
        synchronized (mCachedXmlBlocks) {
            Arrays.fill(mCachedXmlBlockCookies, 0);
            Arrays.fill(mCachedXmlBlockFiles, null);

            final XmlBlock[] cachedXmlBlocks = mCachedXmlBlocks;
            for (int i = 0; i < XML_BLOCK_CACHE_SIZE; i++) {
                final XmlBlock oldBlock = cachedXmlBlocks[i];
                if (oldBlock != null) {
                    oldBlock.close();
                }
            }
            Arrays.fill(cachedXmlBlocks, null);
        }
    }

    /**
     * Start preloading of resource data using this Resources object.  Only
     * for use by the zygote process for loading common system resources.
     * {@hide}
     */
    public final void startPreloading() {
        synchronized (sSync) {
            if (sPreloaded) {
                throw new IllegalStateException("Resources already preloaded");
            }
            sPreloaded = true;
            mPreloading = true;
            mConfiguration.densityDpi = DisplayMetrics.DENSITY_DEVICE;
            updateConfiguration(null, null);
        }
    }

    /**
     * Called by zygote when it is done preloading resources, to change back
     * to normal Resources operation.
     */
    public final void finishPreloading() {
        if (mPreloading) {
            mPreloading = false;
            flushLayoutCache();
        }
    }

    /**
     * @hide
     */
    public LongSparseArray<ConstantState> getPreloadedDrawables() {
        return sPreloadedDrawables[0];
    }

    private boolean verifyPreloadConfig(int changingConfigurations, int allowVarying,
            int resourceId, String name) {
        // We allow preloading of resources even if they vary by font scale (which
        // doesn't impact resource selection) or density (which we handle specially by
        // simply turning off all preloading), as well as any other configs specified
        // by the caller.
        if (((changingConfigurations&~(ActivityInfo.CONFIG_FONT_SCALE |
                ActivityInfo.CONFIG_DENSITY)) & ~allowVarying) != 0) {
            String resName;
            try {
                resName = getResourceName(resourceId);
            } catch (NotFoundException e) {
                resName = "?";
            }
            // This should never happen in production, so we should log a
            // warning even if we're not debugging.
            Log.w(TAG, "Preloaded " + name + " resource #0x"
                    + Integer.toHexString(resourceId)
                    + " (" + resName + ") that varies with configuration!!");
            return false;
        }
        if (TRACE_FOR_PRELOAD) {
            String resName;
            try {
                resName = getResourceName(resourceId);
            } catch (NotFoundException e) {
                resName = "?";
            }
            Log.w(TAG, "Preloading " + name + " resource #0x"
                    + Integer.toHexString(resourceId)
                    + " (" + resName + ")");
        }
        return true;
    }

    @Nullable
    Drawable loadDrawable(TypedValue value, int id, Theme theme) throws NotFoundException {
        return loadDrawable(value, id, theme, true);
    }

    @Nullable
    Drawable loadDrawable(TypedValue value, int id, Theme theme, boolean useCache)
            throws NotFoundException {
        try {
            if (TRACE_FOR_PRELOAD) {
                // Log only framework resources
                if ((id >>> 24) == 0x1) {
                    final String name = getResourceName(id);
                    if (name != null) {
                        Log.d("PreloadDrawable", name);
                    }
                }
            }

            final boolean isColorDrawable;
            final DrawableCache caches;
            final long key;
            if (value.type >= TypedValue.TYPE_FIRST_COLOR_INT
                    && value.type <= TypedValue.TYPE_LAST_COLOR_INT) {
                isColorDrawable = true;
                caches = mColorDrawableCache;
                key = value.data;
            } else {
                isColorDrawable = false;
                caches = mDrawableCache;
                key = (((long) value.assetCookie) << 32) | value.data;
            }

            // First, check whether we have a cached version of this drawable
            // that was inflated against the specified theme. Skip the cache if
            // we're currently preloading or we're not using the cache.
            if (!mPreloading && useCache) {
                final Drawable cachedDrawable = caches.getInstance(key, theme);
                if (cachedDrawable != null) {
                    return cachedDrawable;
                }
            }

            // Next, check preloaded drawables. Preloaded drawables may contain
            // unresolved theme attributes.
            final ConstantState cs;
            if (isColorDrawable) {
                cs = sPreloadedColorDrawables.get(key);
            } else {
                cs = sPreloadedDrawables[mConfiguration.getLayoutDirection()].get(key);
            }

            Drawable dr;
            if (cs != null) {
                dr = cs.newDrawable(this);
            } else if (isColorDrawable) {
                dr = new ColorDrawable(value.data);
            } else {
                dr = loadDrawableForCookie(value, id, null);
            }

            // Determine if the drawable has unresolved theme attributes. If it
            // does, we'll need to apply a theme and store it in a theme-specific
            // cache.
            final boolean canApplyTheme = dr != null && dr.canApplyTheme();
            if (canApplyTheme && theme != null) {
                dr = dr.mutate();
                dr.applyTheme(theme);
                dr.clearMutated();
            }

            // If we were able to obtain a drawable, store it in the appropriate
            // cache: preload, not themed, null theme, or theme-specific. Don't
            // pollute the cache with drawables loaded from a foreign density.
            if (dr != null && useCache) {
                dr.setChangingConfigurations(value.changingConfigurations);
                cacheDrawable(value, isColorDrawable, caches, theme, canApplyTheme, key, dr);
            }

            return dr;
        } catch (Exception e) {
            String name;
            try {
                name = getResourceName(id);
            } catch (NotFoundException e2) {
                name = "(missing name)";
            }

            // The target drawable might fail to load for any number of
            // reasons, but we always want to include the resource name.
            // Since the client already expects this method to throw a
            // NotFoundException, just throw one of those.
            final NotFoundException nfe = new NotFoundException("Drawable " + name
                    + " with resource ID #0x" + Integer.toHexString(id), e);
            nfe.setStackTrace(new StackTraceElement[0]);
            throw nfe;
        }
    }

    private void cacheDrawable(TypedValue value, boolean isColorDrawable, DrawableCache caches,
            Theme theme, boolean usesTheme, long key, Drawable dr) {
        final ConstantState cs = dr.getConstantState();
        if (cs == null) {
            return;
        }

        if (mPreloading) {
            final int changingConfigs = cs.getChangingConfigurations();
            if (isColorDrawable) {
                if (verifyPreloadConfig(changingConfigs, 0, value.resourceId, "drawable")) {
                    sPreloadedColorDrawables.put(key, cs);
                }
            } else {
                if (verifyPreloadConfig(
                        changingConfigs, LAYOUT_DIR_CONFIG, value.resourceId, "drawable")) {
                    if ((changingConfigs & LAYOUT_DIR_CONFIG) == 0) {
                        // If this resource does not vary based on layout direction,
                        // we can put it in all of the preload maps.
                        sPreloadedDrawables[0].put(key, cs);
                        sPreloadedDrawables[1].put(key, cs);
                    } else {
                        // Otherwise, only in the layout dir we loaded it for.
                        sPreloadedDrawables[mConfiguration.getLayoutDirection()].put(key, cs);
                    }
                }
            }
        } else {
            synchronized (mAccessLock) {
                caches.put(key, theme, cs, usesTheme);
            }
        }
    }

    /**
     * Loads a drawable from XML or resources stream.
     */
    private Drawable loadDrawableForCookie(TypedValue value, int id, Theme theme) {
        if (value.string == null) {
            throw new NotFoundException("Resource \"" + getResourceName(id) + "\" ("
                    + Integer.toHexString(id) + ") is not a Drawable (color or path): " + value);
        }

        final String file = value.string.toString();

        if (TRACE_FOR_MISS_PRELOAD) {
            // Log only framework resources
            if ((id >>> 24) == 0x1) {
                final String name = getResourceName(id);
                if (name != null) {
                    Log.d(TAG, "Loading framework drawable #" + Integer.toHexString(id)
                            + ": " + name + " at " + file);
                }
            }
        }

        if (DEBUG_LOAD) {
            Log.v(TAG, "Loading drawable for cookie " + value.assetCookie + ": " + file);
        }

        final Drawable dr;

        Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, file);
        try {
            if (file.endsWith(".xml")) {
                final XmlResourceParser rp = loadXmlResourceParser(
                        file, id, value.assetCookie, "drawable");
                dr = Drawable.createFromXml(this, rp, theme);
                rp.close();
            } else {
                final InputStream is = mAssets.openNonAsset(
                        value.assetCookie, file, AssetManager.ACCESS_STREAMING);
                dr = Drawable.createFromResourceStream(this, value, is, file, null);
                is.close();
            }
        } catch (Exception e) {
            Trace.traceEnd(Trace.TRACE_TAG_RESOURCES);
            final NotFoundException rnf = new NotFoundException(
                    "File " + file + " from drawable resource ID #0x" + Integer.toHexString(id));
            rnf.initCause(e);
            throw rnf;
        }
        Trace.traceEnd(Trace.TRACE_TAG_RESOURCES);

        return dr;
    }

    /**
     * Given the value and id, we can get the XML filename as in value.data, based on that, we
     * first try to load CSL from the cache. If not found, try to get from the constant state.
     * Last, parse the XML and generate the CSL.
     */
    private ComplexColor loadComplexColorFromName(Theme theme, TypedValue value, int id) {
        final long key = (((long) value.assetCookie) << 32) | value.data;
        final ConfigurationBoundResourceCache<ComplexColor> cache = mComplexColorCache;
        ComplexColor complexColor = cache.getInstance(key, theme);
        if (complexColor != null) {
            return complexColor;
        }

        final android.content.res.ConstantState<ComplexColor> factory =
                sPreloadedComplexColors.get(key);

        if (factory != null) {
            complexColor = factory.newInstance(this, theme);
        }
        if (complexColor == null) {
            complexColor = loadComplexColorForCookie(value, id, theme);
        }

        if (complexColor != null) {
            if (mPreloading) {
                if (verifyPreloadConfig(value.changingConfigurations, 0, value.resourceId,
                        "color")) {
                    sPreloadedComplexColors.put(key, complexColor.getConstantState());
                }
            } else {
                cache.put(key, theme, complexColor.getConstantState());
            }
        }
        return complexColor;
    }

    @Nullable
    public ComplexColor loadComplexColor(@NonNull TypedValue value, int id, Theme theme) {
        if (TRACE_FOR_PRELOAD) {
            // Log only framework resources
            if ((id >>> 24) == 0x1) {
                final String name = getResourceName(id);
                if (name != null) android.util.Log.d("loadComplexColor", name);
            }
        }

        final long key = (((long) value.assetCookie) << 32) | value.data;

        // Handle inline color definitions.
        if (value.type >= TypedValue.TYPE_FIRST_COLOR_INT
                && value.type <= TypedValue.TYPE_LAST_COLOR_INT) {
            return getColorStateListFromInt(value, key);
        }

        final String file = value.string.toString();

        ComplexColor complexColor;
        if (file.endsWith(".xml")) {
            try {
                complexColor = loadComplexColorFromName(theme, value, id);
            } catch (Exception e) {
                final NotFoundException rnf = new NotFoundException(
                        "File " + file + " from complex color resource ID #0x"
                                + Integer.toHexString(id));
                rnf.initCause(e);
                throw rnf;
            }
        } else {
            throw new NotFoundException(
                    "File " + file + " from drawable resource ID #0x"
                            + Integer.toHexString(id) + ": .xml extension required");
        }

        return complexColor;
    }

    @Nullable
    ColorStateList loadColorStateList(TypedValue value, int id, Theme theme)
            throws NotFoundException {
        if (TRACE_FOR_PRELOAD) {
            // Log only framework resources
            if ((id >>> 24) == 0x1) {
                final String name = getResourceName(id);
                if (name != null) android.util.Log.d("PreloadColorStateList", name);
            }
        }

        final long key = (((long) value.assetCookie) << 32) | value.data;

        // Handle inline color definitions.
        if (value.type >= TypedValue.TYPE_FIRST_COLOR_INT
                && value.type <= TypedValue.TYPE_LAST_COLOR_INT) {
            return getColorStateListFromInt(value, key);
        }

        ComplexColor complexColor = loadComplexColorFromName(theme, value, id);
        if (complexColor != null && complexColor instanceof ColorStateList) {
            return (ColorStateList) complexColor;
        }

        throw new NotFoundException(
                "Can't find ColorStateList from drawable resource ID #0x"
                        + Integer.toHexString(id));
    }

    @NonNull
    private ColorStateList getColorStateListFromInt(@NonNull  TypedValue value, long key) {
        ColorStateList csl;
        final android.content.res.ConstantState<ComplexColor> factory =
                sPreloadedComplexColors.get(key);
        if (factory != null) {
            return (ColorStateList) factory.newInstance();
        }

        csl = ColorStateList.valueOf(value.data);

        if (mPreloading) {
            if (verifyPreloadConfig(value.changingConfigurations, 0, value.resourceId,
                    "color")) {
                sPreloadedComplexColors.put(key, csl.getConstantState());
            }
        }

        return csl;
    }

    /**
     * Load a ComplexColor based on the XML file content. The result can be a GradientColor or
     * ColorStateList. Note that pure color will be wrapped into a ColorStateList.
     *
     * We deferred the parser creation to this function b/c we need to differentiate b/t gradient
     * and selector tag.
     *
     * @return a ComplexColor (GradientColor or ColorStateList) based on the XML file content.
     */
    @Nullable
    private ComplexColor loadComplexColorForCookie(TypedValue value, int id, Theme theme) {
        if (value.string == null) {
            throw new UnsupportedOperationException(
                    "Can't convert to ComplexColor: type=0x" + value.type);
        }

        final String file = value.string.toString();

        if (TRACE_FOR_MISS_PRELOAD) {
            // Log only framework resources
            if ((id >>> 24) == 0x1) {
                final String name = getResourceName(id);
                if (name != null) {
                    Log.d(TAG, "Loading framework ComplexColor #" + Integer.toHexString(id)
                            + ": " + name + " at " + file);
                }
            }
        }

        if (DEBUG_LOAD) {
            Log.v(TAG, "Loading ComplexColor for cookie " + value.assetCookie + ": " + file);
        }

        ComplexColor complexColor = null;

        Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, file);
        if (file.endsWith(".xml")) {
            try {
                final XmlResourceParser parser = loadXmlResourceParser(
                        file, id, value.assetCookie, "ComplexColor");

                final AttributeSet attrs = Xml.asAttributeSet(parser);
                int type;
                while ((type = parser.next()) != XmlPullParser.START_TAG
                        && type != XmlPullParser.END_DOCUMENT) {
                    // Seek parser to start tag.
                }
                if (type != XmlPullParser.START_TAG) {
                    throw new XmlPullParserException("No start tag found");
                }

                final String name = parser.getName();
                if (name.equals("gradient")) {
                    complexColor = GradientColor.createFromXmlInner(this, parser, attrs, theme);
                } else if (name.equals("selector")) {
                    complexColor = ColorStateList.createFromXmlInner(this, parser, attrs, theme);
                }
                parser.close();
            } catch (Exception e) {
                Trace.traceEnd(Trace.TRACE_TAG_RESOURCES);
                final NotFoundException rnf = new NotFoundException(
                        "File " + file + " from ComplexColor resource ID #0x"
                                + Integer.toHexString(id));
                rnf.initCause(e);
                throw rnf;
            }
        } else {
            Trace.traceEnd(Trace.TRACE_TAG_RESOURCES);
            throw new NotFoundException(
                    "File " + file + " from drawable resource ID #0x"
                            + Integer.toHexString(id) + ": .xml extension required");
        }
        Trace.traceEnd(Trace.TRACE_TAG_RESOURCES);

        return complexColor;
    }

    /**
     * Loads an XML parser for the specified file.
     *
     * @param id the resource identifier for the file
     * @param type the type of resource (used for logging)
     * @return a parser for the specified XML file
     * @throws NotFoundException if the file could not be loaded
     */
    @NonNull
    XmlResourceParser loadXmlResourceParser(@AnyRes int id, @NonNull String type)
            throws NotFoundException {
        final TypedValue value = obtainTempTypedValue(id);
        try {
            if (value.type == TypedValue.TYPE_STRING) {
                return loadXmlResourceParser(value.string.toString(), id,
                        value.assetCookie, type);
            }
            throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
                    + " type #0x" + Integer.toHexString(value.type) + " is not valid");
        } finally {
            releaseTempTypedValue(value);
        }
    }

    /**
     * Loads an XML parser for the specified file.
     *
     * @param file the path for the XML file to parse
     * @param id the resource identifier for the file
     * @param assetCookie the asset cookie for the file
     * @param type the type of resource (used for logging)
     * @return a parser for the specified XML file
     * @throws NotFoundException if the file could not be loaded
     */
    @NonNull
    XmlResourceParser loadXmlResourceParser(@NonNull String file, @AnyRes int id,
            int assetCookie, @NonNull String type) throws NotFoundException {
        if (id != 0) {
            try {
                synchronized (mCachedXmlBlocks) {
                    final int[] cachedXmlBlockCookies = mCachedXmlBlockCookies;
                    final String[] cachedXmlBlockFiles = mCachedXmlBlockFiles;
                    final XmlBlock[] cachedXmlBlocks = mCachedXmlBlocks;
                    // First see if this block is in our cache.
                    final int num = cachedXmlBlockFiles.length;
                    for (int i = 0; i < num; i++) {
                        if (cachedXmlBlockCookies[i] == assetCookie && cachedXmlBlockFiles[i] != null
                                && cachedXmlBlockFiles[i].equals(file)) {
                            return cachedXmlBlocks[i].newParser();
                        }
                    }

                    // Not in the cache, create a new block and put it at
                    // the next slot in the cache.
                    final XmlBlock block = mAssets.openXmlBlockAsset(assetCookie, file);
                    if (block != null) {
                        final int pos = (mLastCachedXmlBlockIndex + 1) % num;
                        mLastCachedXmlBlockIndex = pos;
                        final XmlBlock oldBlock = cachedXmlBlocks[pos];
                        if (oldBlock != null) {
                            oldBlock.close();
                        }
                        cachedXmlBlockCookies[pos] = assetCookie;
                        cachedXmlBlockFiles[pos] = file;
                        cachedXmlBlocks[pos] = block;
                        return block.newParser();
                    }
                }
            } catch (Exception e) {
                final NotFoundException rnf = new NotFoundException("File " + file
                        + " from xml type " + type + " resource ID #0x" + Integer.toHexString(id));
                rnf.initCause(e);
                throw rnf;
            }
        }

        throw new NotFoundException("File " + file + " from xml type " + type + " resource ID #0x"
                + Integer.toHexString(id));
    }

    /**
     * Obtains styled attributes from the theme, if available, or unstyled
     * resources if the theme is null.
     *
     * @hide
     */
    public static TypedArray obtainAttributes(
            Resources res, Theme theme, AttributeSet set, int[] attrs) {
        if (theme == null) {
            return res.obtainAttributes(set, attrs);
        }
        return theme.obtainStyledAttributes(set, attrs, 0, 0);
    }

    private Resources() {
        mAssets = AssetManager.getSystem();
        mClassLoader = ClassLoader.getSystemClassLoader();
        // NOTE: Intentionally leaving this uninitialized (all values set
        // to zero), so that anyone who tries to do something that requires
        // metrics will get a very wrong value.
        mConfiguration.setToDefaults();
        mMetrics.setToDefaults();
        updateConfiguration(null, null);
        mAssets.ensureStringBlocks();
    }
}