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.graphics.Movie;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.ColorDrawable;
import android.os.SystemProperties;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.SparseArray;
import android.util.TypedValue;

import java.io.InputStream;
import java.lang.ref.WeakReference;

/**
 * Class for accessing an application's resources.  This sits on top of the
 * asset manager of the application (accessible through getAssets()) and
 * provides a higher-level API for getting typed data from the assets.
 */
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 int sSdkVersion = SystemProperties.getInt(
            "ro.build.version.sdk", 0);
    private static final Object mSync = new Object();
    private static Resources mSystem = null;

    // 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 SparseArray<Drawable.ConstantState> mPreloadedDrawables
            = new SparseArray<Drawable.ConstantState>();
    private static boolean mPreloaded;

    /*package*/ final TypedValue mTmpValue = new TypedValue();

    // These are protected by the mTmpValue lock.
    private final SparseArray<WeakReference<Drawable.ConstantState> > mDrawableCache
            = new SparseArray<WeakReference<Drawable.ConstantState> >();
    private final SparseArray<WeakReference<ColorStateList> > mColorStateListCache
            = new SparseArray<WeakReference<ColorStateList> >();
    private boolean mPreloading;

    /*package*/ TypedArray mCachedStyledAttributes = null;

    private int mLastCachedXmlBlockIndex = -1;
    private final int[] mCachedXmlBlockIds = { 0, 0, 0, 0 };
    private final XmlBlock[] mCachedXmlBlocks = new XmlBlock[4];

    /*package*/ final AssetManager mAssets;
    private final Configuration mConfiguration = new Configuration();
    /*package*/ final DisplayMetrics mMetrics = new DisplayMetrics();
    PluralRule mPluralRule;

    /**
     * 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);
        }
    };

    /**
     * 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) {
        mAssets = assets;
        mConfiguration.setToDefaults();
        mMetrics.setToDefaults();
        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 (mSync) {
            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(int id) throws NotFoundException {
        CharSequence res = mAssets.getResourceText(id);
        if (res != null) {
            return res;
        }
        throw new NotFoundException("String resource ID #0x"
                                    + Integer.toHexString(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 CharSequence The string data associated with the resource, plus
     *         possibly styled text information.
     */
    public CharSequence getQuantityText(int id, int quantity) throws NotFoundException {
        PluralRule rule = getPluralRule();
        CharSequence res = mAssets.getResourceBagText(id, rule.attrForNumber(quantity));
        if (res != null) {
            return res;
        }
        res = mAssets.getResourceBagText(id, PluralRule.ID_OTHER);
        if (res != null) {
            return res;
        }
        throw new NotFoundException("Plural resource ID #0x" + Integer.toHexString(id)
                + " quantity=" + quantity
                + " item=" + PluralRule.stringForQuantity(rule.quantityForNumber(quantity)));
    }

    private PluralRule getPluralRule() {
        synchronized (mSync) {
            if (mPluralRule == null) {
                mPluralRule = PluralRule.ruleForLocale(mConfiguration.locale);
            }
            return mPluralRule;
        }
    }

    /**
     * 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.
     */
    public String getString(int id) throws NotFoundException {
        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.
     */
    public String getString(int id, Object... formatArgs) throws NotFoundException {
        String raw = getString(id);
        return String.format(mConfiguration.locale, raw, formatArgs);
    }

    /**
     * Return the string value associated with a particular resource ID for a particular
     * numerical quantity, 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 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(int id, int quantity, Object... formatArgs)
            throws NotFoundException {
        String raw = getQuantityText(id, quantity).toString();
        return String.format(mConfiguration.locale, raw, formatArgs);
    }

    /**
     * Return the string value associated with a particular resource ID for a particular
     * numerical quantity.
     *
     * @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(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(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(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(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(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(int id) throws NotFoundException {
        int len = mAssets.getArraySize(id);
        if (len < 0) {
            throw new NotFoundException("Array resource ID #0x"
                                        + Integer.toHexString(id));
        }

        TypedArray array = getCachedStyledAttributes(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.
     *
     * @return CharSequence The string data associated with the resource, plus
     * @see #getDimensionPixelOffset
     * @see #getDimensionPixelSize
     */
    public float getDimension(int id) throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            getValue(id, value, true);
            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");
        }
    }

    /**
     * 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.
     *
     * @return CharSequence The string data associated with the resource, plus
     * @see #getDimension
     * @see #getDimensionPixelSize
     */
    public int getDimensionPixelOffset(int id) throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            getValue(id, value, true);
            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");
        }
    }

    /**
     * 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.
     *
     * @return CharSequence The string data associated with the resource, plus
     * @see #getDimension
     * @see #getDimensionPixelOffset
     */
    public int getDimensionPixelSize(int id) throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            getValue(id, value, true);
            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");
        }
    }

    /**
     * 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.
     *
     * @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 Drawable An object that can be used to draw this resource.
     */
    public Drawable getDrawable(int id) throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            getValue(id, value, true);
            return loadDrawable(value, id);
        }
    }

    /**
     * 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(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;
    }

    /**
     * Return a color integer associated with a particular resource ID.
     * If the resource holds a complex
     * {@link android.content.res.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 Returns a single color value in the form 0xAARRGGBB.
     */
    public int getColor(int id) throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            getValue(id, value, true);
            if (value.type >= TypedValue.TYPE_FIRST_INT
                && value.type <= TypedValue.TYPE_LAST_INT) {
                return value.data;
            } else if (value.type == TypedValue.TYPE_STRING) {
                ColorStateList csl = loadColorStateList(mTmpValue, id);
                return csl.getDefaultColor();
            }
            throw new NotFoundException(
                "Resource ID #0x" + Integer.toHexString(id) + " type #0x"
                + Integer.toHexString(value.type) + " is not valid");
        }
    }

    /**
     * Return a color state list associated with a particular resource ID.  The
     * resource may contain either a single raw color value, or a complex
     * {@link android.content.res.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 Returns a ColorStateList object containing either a single
     * solid color or multiple colors that can be selected based on a state.
     */
    public ColorStateList getColorStateList(int id) throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            getValue(id, value, true);
            return loadColorStateList(value, id);
        }
    }

    /**
     * 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(int id) throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            getValue(id, value, true);
            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");
        }
    }

    /**
     * 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(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(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(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(int id) throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            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(int id) throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            getValue(id, value, true);

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

        }
    }

    /**
     * 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(int id, TypedValue outValue, boolean resolveRefs)
            throws NotFoundException {
        boolean found = mAssets.getResourceValue(id, 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) {
            AssetManager.applyThemeStyle(mTheme, 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) {
            AssetManager.copyTheme(mTheme, other.mTheme);
        }

        /**
         * Return a StyledAttributes holding the values defined by
         * <var>Theme</var> which are listed in <var>attrs</var>.
         *
         * <p>Be sure to call StyledAttributes.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(int[] attrs) {
            int len = attrs.length;
            TypedArray array = getCachedStyledAttributes(len);
            array.mRsrcs = attrs;
            AssetManager.applyStyle(mTheme, 0, 0, 0, attrs,
                    array.mData, array.mIndices);
            return array;
        }

        /**
         * Return a StyledAttributes holding the values defined by the style
         * resource <var>resid</var> which are listed in <var>attrs</var>.
         *
         * <p>Be sure to call StyledAttributes.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(int resid, int[] attrs)
                throws NotFoundException {
            int len = attrs.length;
            TypedArray array = getCachedStyledAttributes(len);
            array.mRsrcs = attrs;

            AssetManager.applyStyle(mTheme, 0, resid, 0, attrs,
                    array.mData, array.mIndices);
            if (false) {
                int[] data = array.mData;

                System.out.println("**********************************************************");
                System.out.println("**********************************************************");
                System.out.println("**********************************************************");
                System.out.println("Attributes:");
                String s = "  Attrs:";
                int i;
                for (i=0; i<attrs.length; i++) {
                    s = s + " 0x" + Integer.toHexString(attrs[i]);
                }
                System.out.println(s);
                s = "  Found:";
                TypedValue value = new TypedValue();
                for (i=0; i<attrs.length; i++) {
                    int d = i*AssetManager.STYLE_NUM_ENTRIES;
                    value.type = data[d+AssetManager.STYLE_TYPE];
                    value.data = data[d+AssetManager.STYLE_DATA];
                    value.assetCookie = data[d+AssetManager.STYLE_ASSET_COOKIE];
                    value.resourceId = data[d+AssetManager.STYLE_RESOURCE_ID];
                    s = s + " 0x" + Integer.toHexString(attrs[i])
                        + "=" + value;
                }
                System.out.println(s);
            }
            return array;
        }

        /**
         * Return a StyledAttributes 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 StyledAttributes.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 StyledAttributes.  Can be
         *                     0 to not look for defaults.
         * @param defStyleRes A resource identifier of a style resource that
         *                    supplies default values for the StyledAttributes,
         *                    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,
                int[] attrs, int defStyleAttr, int defStyleRes) {
            int len = attrs.length;
            TypedArray array = getCachedStyledAttributes(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;
            AssetManager.applyStyle(
                mTheme, defStyleAttr, defStyleRes,
                parser != null ? parser.mParseState : 0, attrs,
                        array.mData, array.mIndices);

            array.mRsrcs = attrs;
            array.mXml = parser;

            if (false) {
                int[] data = array.mData;

                System.out.println("Attributes:");
                String s = "  Attrs:";
                int i;
                for (i=0; i<set.getAttributeCount(); i++) {
                    s = s + " " + set.getAttributeName(i);
                    int id = set.getAttributeNameResource(i);
                    if (id != 0) {
                        s = s + "(0x" + Integer.toHexString(id) + ")";
                    }
                    s = s + "=" + set.getAttributeValue(i);
                }
                System.out.println(s);
                s = "  Found:";
                TypedValue value = new TypedValue();
                for (i=0; i<attrs.length; i++) {
                    int d = i*AssetManager.STYLE_NUM_ENTRIES;
                    value.type = data[d+AssetManager.STYLE_TYPE];
                    value.data = data[d+AssetManager.STYLE_DATA];
                    value.assetCookie = data[d+AssetManager.STYLE_ASSET_COOKIE];
                    value.resourceId = data[d+AssetManager.STYLE_RESOURCE_ID];
                    s = s + " 0x" + Integer.toHexString(attrs[i])
                        + "=" + value;
                }
                System.out.println(s);
            }

            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) {
            boolean got = mAssets.getThemeValue(mTheme, resid, outValue, resolveRefs);
            if (false) {
                System.out.println(
                    "resolveAttribute #" + Integer.toHexString(resid)
                    + " got=" + got + ", type=0x" + Integer.toHexString(outValue.type)
                    + ", data=0x" + Integer.toHexString(outValue.data));
            }
            return got;
        }

        /**
         * 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) {
            AssetManager.dumpTheme(mTheme, priority, tag, prefix);
        }

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

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

        private final AssetManager mAssets;
        private final int mTheme;
    }

    /**
     * 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 = getCachedStyledAttributes(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.mRsrcs = attrs;
        array.mXml = parser;

        return array;
    }

    /**
     * Store the newly updated configuration.
     */
    public void updateConfiguration(Configuration config,
            DisplayMetrics metrics) {
        synchronized (mTmpValue) {
            int configChanges = 0xfffffff;
            if (config != null) {
                configChanges = mConfiguration.updateFrom(config);
            }
            if (metrics != null) {
                mMetrics.setTo(metrics);
            }
            mMetrics.scaledDensity = mMetrics.density * mConfiguration.fontScale;
            String locale = null;
            if (mConfiguration.locale != null) {
                locale = mConfiguration.locale.getLanguage();
                if (mConfiguration.locale.getCountry() != null) {
                    locale += "-" + mConfiguration.locale.getCountry();
                }
            }
            int width, height;
            if (mMetrics.widthPixels >= mMetrics.heightPixels) {
                width = mMetrics.widthPixels;
                height = mMetrics.heightPixels;
            } else {
                width = mMetrics.heightPixels;
                height = mMetrics.widthPixels;
            }
            mAssets.setConfiguration(mConfiguration.mcc, mConfiguration.mnc,
                    locale, mConfiguration.orientation,
                    mConfiguration.touchscreen,
                    (int)(mMetrics.density*160), mConfiguration.keyboard,
                    mConfiguration.keyboardHidden,
                    mConfiguration.navigation, width, height, sSdkVersion);
            int N = mDrawableCache.size();
            if (DEBUG_CONFIG) {
                Log.d(TAG, "Cleaning up drawables config changes: 0x"
                        + Integer.toHexString(configChanges));
            }
            for (int i=0; i<N; i++) {
                WeakReference<Drawable.ConstantState> ref = mDrawableCache.valueAt(i);
                if (ref != null) {
                    Drawable.ConstantState cs = ref.get();
                    if (cs != null) {
                        if (Configuration.needNewResources(
                                configChanges, cs.getChangingConfigurations())) {
                            if (DEBUG_CONFIG) {
                                Log.d(TAG, "FLUSHING #0x"
                                        + Integer.toHexString(mDrawableCache.keyAt(i))
                                        + " / " + cs + " with changes: 0x"
                                        + Integer.toHexString(cs.getChangingConfigurations()));
                            }
                            mDrawableCache.setValueAt(i, null);
                        } else if (DEBUG_CONFIG) {
                            Log.d(TAG, "(Keeping #0x"
                                    + Integer.toHexString(mDrawableCache.keyAt(i))
                                    + " / " + cs + " with changes: 0x"
                                    + Integer.toHexString(cs.getChangingConfigurations())
                                    + ")");
                        }
                    }
                }
            }
            mDrawableCache.clear();
            mColorStateListCache.clear();
            flushLayoutCache();
        }
        synchronized (mSync) {
            if (mPluralRule != null) {
                mPluralRule = PluralRule.ruleForLocale(config.locale);
            }
        }
    }

    /**
     * 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() {
        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;
    }

    /**
     * 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) {
        try {
            return Integer.parseInt(name);
        } catch (Exception e) {
        }
        return mAssets.getResourceIdentifier(name, defType, defPackage);
    }

    /**
     * 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(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(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(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(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));
    }

    /**
     * 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 (mCachedXmlBlockIds) {
            // First see if this block is in our cache.
            final int num = mCachedXmlBlockIds.length;
            for (int i=0; i<num; i++) {
                mCachedXmlBlockIds[i] = -0;
                XmlBlock oldBlock = mCachedXmlBlocks[i];
                if (oldBlock != null) {
                    oldBlock.close();
                }
                mCachedXmlBlocks[i] = 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 (mSync) {
            if (mPreloaded) {
                throw new IllegalStateException("Resources already preloaded");
            }
            mPreloaded = true;
            mPreloading = true;
        }
    }

    /**
     * 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();
        }
    }

    /*package*/ Drawable loadDrawable(TypedValue value, int id)
            throws NotFoundException {
        if (value.type >= TypedValue.TYPE_FIRST_COLOR_INT
            && value.type <= TypedValue.TYPE_LAST_COLOR_INT) {
            // Should we be caching these?  If we use constant colors much
            // at all, most likely...
            //System.out.println("Creating drawable for color: #" +
            //                   Integer.toHexString(value.data));
            Drawable dr = new ColorDrawable(value.data);
            dr.setChangingConfigurations(value.changingConfigurations);
            return dr;
        }

        final int key = (value.assetCookie<<24)|value.data;
        Drawable dr = getCachedDrawable(key);
        //System.out.println("Cached drawable @ #" +
        //                   Integer.toHexString(key.intValue()) + ": " + dr);
        if (dr != null) {
            return dr;
        }

        Drawable.ConstantState cs = mPreloadedDrawables.get(key);
        if (cs != null) {
            dr = cs.newDrawable();

        } else {
            if (value.string == null) {
                throw new NotFoundException(
                        "Resource is not a Drawable (color or path): " + value);
            }

            String file = value.string.toString();

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

            if (file.endsWith(".xml")) {
                try {
                    XmlResourceParser rp = loadXmlResourceParser(
                            file, id, value.assetCookie, "drawable");
                    dr = Drawable.createFromXml(this, rp);
                    rp.close();
                } catch (Exception e) {
                    NotFoundException rnf = new NotFoundException(
                        "File " + file + " from drawable resource ID #0x"
                        + Integer.toHexString(id));
                    rnf.initCause(e);
                    throw rnf;
                }

            } else {
                try {
                    InputStream is = mAssets.openNonAsset(
                            value.assetCookie, file, AssetManager.ACCESS_BUFFER);
    //                System.out.println("Opened file " + file + ": " + is);
                    dr = Drawable.createFromStream(is, file);
                    is.close();
    //                System.out.println("Created stream: " + dr);
                } catch (Exception e) {
                    NotFoundException rnf = new NotFoundException(
                        "File " + file + " from drawable resource ID #0x"
                        + Integer.toHexString(id));
                    rnf.initCause(e);
                    throw rnf;
                }
            }
        }

        if (dr != null) {
            dr.setChangingConfigurations(value.changingConfigurations);
            cs = dr.getConstantState();
            if (cs != null) {
                if (mPreloading) {
                    mPreloadedDrawables.put(key, cs);
                }
                synchronized (mTmpValue) {
                    //Log.i(TAG, "Saving cached drawable @ #" +
                    //        Integer.toHexString(key.intValue())
                    //        + " in " + this + ": " + cs);
                    mDrawableCache.put(
                        key, new WeakReference<Drawable.ConstantState>(cs));
                }
            }
        }

        return dr;
    }

    private final Drawable getCachedDrawable(int key) {
        synchronized (mTmpValue) {
            WeakReference<Drawable.ConstantState> wr = mDrawableCache.get(key);
            if (wr != null) {   // we have the key
                Drawable.ConstantState entry = wr.get();
                if (entry != null) {
                    //Log.i(TAG, "Returning cached drawable @ #" +
                    //        Integer.toHexString(((Integer)key).intValue())
                    //        + " in " + this + ": " + entry);
                    return entry.newDrawable();
                }
                else {  // our entry has been purged
                    mDrawableCache.delete(key);
                }
            }
        }
        return null;
    }

    /*package*/ ColorStateList loadColorStateList(TypedValue value, int id)
            throws NotFoundException {
        if (value.type >= TypedValue.TYPE_FIRST_COLOR_INT
            && value.type <= TypedValue.TYPE_LAST_COLOR_INT) {
            return ColorStateList.valueOf(value.data);
        }

        final int key = (value.assetCookie<<24)|value.data;
        ColorStateList csl = getCachedColorStateList(key);
        if (csl != null) {
            return csl;
        }

        if (value.string == null) {
            throw new NotFoundException(
                    "Resource is not a ColorStateList (color or path): " + value);
        }

        String file = value.string.toString();

        if (file.endsWith(".xml")) {
            try {
                XmlResourceParser rp = loadXmlResourceParser(
                        file, id, value.assetCookie, "colorstatelist");
                csl = ColorStateList.createFromXml(this, rp);
                rp.close();
            } catch (Exception e) {
                NotFoundException rnf = new NotFoundException(
                    "File " + file + " from color state list 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");
        }

        if (csl != null) {
            synchronized (mTmpValue) {
                //Log.i(TAG, "Saving cached color state list @ #" +
                //        Integer.toHexString(key.intValue())
                //        + " in " + this + ": " + csl);
                mColorStateListCache.put(
                    key, new WeakReference<ColorStateList>(csl));
            }
        }

        return csl;
    }

    private ColorStateList getCachedColorStateList(int key) {
        synchronized (mTmpValue) {
            WeakReference<ColorStateList> wr = mColorStateListCache.get(key);
            if (wr != null) {   // we have the key
                ColorStateList entry = wr.get();
                if (entry != null) {
                    //Log.i(TAG, "Returning cached color state list @ #" +
                    //        Integer.toHexString(((Integer)key).intValue())
                    //        + " in " + this + ": " + entry);
                    return entry;
                }
                else {  // our entry has been purged
                    mColorStateListCache.delete(key);
                }
            }
        }
        return null;
    }

    /*package*/ XmlResourceParser loadXmlResourceParser(int id, String type)
            throws NotFoundException {
        synchronized (mTmpValue) {
            TypedValue value = mTmpValue;
            getValue(id, value, true);
            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");
        }
    }

    /*package*/ XmlResourceParser loadXmlResourceParser(String file, int id,
            int assetCookie, String type) throws NotFoundException {
        if (id != 0) {
            try {
                // These may be compiled...
                synchronized (mCachedXmlBlockIds) {
                    // First see if this block is in our cache.
                    final int num = mCachedXmlBlockIds.length;
                    for (int i=0; i<num; i++) {
                        if (mCachedXmlBlockIds[i] == id) {
                            //System.out.println("**** REUSING XML BLOCK!  id="
                            //                   + id + ", index=" + i);
                            return mCachedXmlBlocks[i].newParser();
                        }
                    }

                    // Not in the cache, create a new block and put it at
                    // the next slot in the cache.
                    XmlBlock block = mAssets.openXmlBlockAsset(
                            assetCookie, file);
                    if (block != null) {
                        int pos = mLastCachedXmlBlockIndex+1;
                        if (pos >= num) pos = 0;
                        mLastCachedXmlBlockIndex = pos;
                        XmlBlock oldBlock = mCachedXmlBlocks[pos];
                        if (oldBlock != null) {
                            oldBlock.close();
                        }
                        mCachedXmlBlockIds[pos] = id;
                        mCachedXmlBlocks[pos] = block;
                        //System.out.println("**** CACHING NEW XML BLOCK!  id="
                        //                   + id + ", index=" + pos);
                        return block.newParser();
                    }
                }
            } catch (Exception e) {
                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));
    }

    private TypedArray getCachedStyledAttributes(int len) {
        synchronized (mTmpValue) {
            TypedArray attrs = mCachedStyledAttributes;
            if (attrs != null) {
                mCachedStyledAttributes = null;

                attrs.mLength = len;
                int fullLen = len * AssetManager.STYLE_NUM_ENTRIES;
                if (attrs.mData.length >= fullLen) {
                    return attrs;
                }
                attrs.mData = new int[fullLen];
                attrs.mIndices = new int[1+len];
                return attrs;
            }
            return new TypedArray(this,
                    new int[len*AssetManager.STYLE_NUM_ENTRIES],
                    new int[1+len], len);
        }
    }

    private Resources() {
        mAssets = AssetManager.getSystem();
        // 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();
    }
}