inputmethod/keyboard/Keyboard.java

/*
 * Copyright (C) 2010 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 com.android.inputmethod.keyboard;

import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.content.res.XmlResourceParser;
import android.text.TextUtils;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.TypedValue;
import android.util.Xml;
import android.view.InflateException;

import com.android.inputmethod.compat.EditorInfoCompatUtils;
import com.android.inputmethod.keyboard.internal.KeyStyles;
import com.android.inputmethod.keyboard.internal.KeyboardIconsSet;
import com.android.inputmethod.keyboard.internal.KeyboardShiftState;
import com.android.inputmethod.latin.LatinImeLogger;
import com.android.inputmethod.latin.R;
import com.android.inputmethod.latin.XmlParseUtils;

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

import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 * Loads an XML description of a keyboard and stores the attributes of the keys. A keyboard
 * consists of rows of keys.
 * <p>The layout file for a keyboard contains XML that looks like the following snippet:</p>
 * <pre>
 * &lt;Keyboard
 *         latin:keyWidth="%10p"
 *         latin:keyHeight="50px"
 *         latin:horizontalGap="2px"
 *         latin:verticalGap="2px" &gt;
 *     &lt;Row latin:keyWidth="32px" &gt;
 *         &lt;Key latin:keyLabel="A" /&gt;
 *         ...
 *     &lt;/Row&gt;
 *     ...
 * &lt;/Keyboard&gt;
 * </pre>
 */
public class Keyboard {
    private static final String TAG = Keyboard.class.getSimpleName();

    /** Some common keys code. Must be positive.
     * These should be aligned with values/keycodes.xml
     */
    public static final int CODE_ENTER = '\n';
    public static final int CODE_TAB = '\t';
    public static final int CODE_SPACE = ' ';
    public static final int CODE_PERIOD = '.';
    public static final int CODE_DASH = '-';
    public static final int CODE_SINGLE_QUOTE = '\'';
    public static final int CODE_DOUBLE_QUOTE = '"';
    // TODO: Check how this should work for right-to-left languages. It seems to stand
    // that for rtl languages, a closing parenthesis is a left parenthesis. Is this
    // managed by the font? Or is it a different char?
    public static final int CODE_CLOSING_PARENTHESIS = ')';
    public static final int CODE_CLOSING_SQUARE_BRACKET = ']';
    public static final int CODE_CLOSING_CURLY_BRACKET = '}';
    public static final int CODE_CLOSING_ANGLE_BRACKET = '>';
    public static final int CODE_DIGIT0 = '0';
    public static final int CODE_PLUS = '+';
    private static final int MINIMUM_LETTER_CODE = CODE_TAB;

    /** Special keys code. Must be negative.
     * These should be aligned with values/keycodes.xml
     */
    public static final int CODE_SHIFT = -1;
    public static final int CODE_SWITCH_ALPHA_SYMBOL = -2;
    public static final int CODE_CAPSLOCK = -3;
    public static final int CODE_OUTPUT_TEXT = -4;
    public static final int CODE_DELETE = -5;
    public static final int CODE_SETTINGS = -6;
    public static final int CODE_SHORTCUT = -7;
    // Code value representing the code is not specified.
    public static final int CODE_UNSPECIFIED = -9;

    public final KeyboardId mId;
    public final int mThemeId;

    /** Total height of the keyboard, including the padding and keys */
    public final int mOccupiedHeight;
    /** Total width of the keyboard, including the padding and keys */
    public final int mOccupiedWidth;

    /** The padding above the keyboard */
    public final int mTopPadding;
    /** Default gap between rows */
    public final int mVerticalGap;

    public final int mMostCommonKeyHeight;
    public final int mMostCommonKeyWidth;

    /** More keys keyboard template */
    public final int mMoreKeysTemplate;

    /** Maximum column for mini keyboard */
    public final int mMaxMiniKeyboardColumn;

    /** True if Right-To-Left keyboard */
    public final boolean mIsRtlKeyboard;

    /** List of keys and icons in this keyboard */
    public final Set<Key> mKeys;
    public final Set<Key> mShiftKeys;
    public final Set<Key> mShiftLockKeys;
    public final KeyboardIconsSet mIconsSet;

    private final Map<Integer, Key> mKeyCache = new HashMap<Integer, Key>();

    private final ProximityInfo mProximityInfo;

    // TODO: Remove this variable.
    private final KeyboardShiftState mShiftState = new KeyboardShiftState();

    public Keyboard(Params params) {
        mId = params.mId;
        mThemeId = params.mThemeId;
        mOccupiedHeight = params.mOccupiedHeight;
        mOccupiedWidth = params.mOccupiedWidth;
        mMostCommonKeyHeight = params.mMostCommonKeyHeight;
        mMostCommonKeyWidth = params.mMostCommonKeyWidth;
        mIsRtlKeyboard = params.mIsRtlKeyboard;
        mMoreKeysTemplate = params.mMoreKeysTemplate;
        mMaxMiniKeyboardColumn = params.mMaxMiniKeyboardColumn;

        mTopPadding = params.mTopPadding;
        mVerticalGap = params.mVerticalGap;

        mKeys = Collections.unmodifiableSet(params.mKeys);
        mShiftKeys = Collections.unmodifiableSet(params.mShiftKeys);
        mShiftLockKeys = Collections.unmodifiableSet(params.mShiftLockKeys);
        mIconsSet = params.mIconsSet;

        mProximityInfo = new ProximityInfo(
                params.GRID_WIDTH, params.GRID_HEIGHT, mOccupiedWidth, mOccupiedHeight,
                mMostCommonKeyWidth, mMostCommonKeyHeight, mKeys, params.mTouchPositionCorrection);
    }

    public ProximityInfo getProximityInfo() {
        return mProximityInfo;
    }

    public Key getKey(int code) {
        if (code == CODE_UNSPECIFIED) {
            return null;
        }
        final Integer keyCode = code;
        if (mKeyCache.containsKey(keyCode)) {
            return mKeyCache.get(keyCode);
        }

        for (final Key key : mKeys) {
            if (key.mCode == code) {
                mKeyCache.put(keyCode, key);
                return key;
            }
        }
        mKeyCache.put(keyCode, null);
        return null;
    }

    // TODO: Remove this method.
    boolean hasShiftLockKey() {
        return !mShiftLockKeys.isEmpty();
    }

    // TODO: Remove this method.
    void setShiftLocked(boolean newShiftLockState) {
        for (final Key key : mShiftLockKeys) {
            // To represent "shift locked" state. The highlight is handled by background image that
            // might be a StateListDrawable.
            key.setHighlightOn(newShiftLockState);
            final int attrId = newShiftLockState
                    ? R.styleable.Keyboard_iconShiftKeyShifted
                    : R.styleable.Keyboard_iconShiftKey;
            key.setIcon(mIconsSet.getIconByAttrId(attrId));
        }
        mShiftState.setShiftLocked(newShiftLockState);
    }

    // TODO: Move this method to KeyboardId.
    public boolean isShiftLocked() {
        return mShiftState.isShiftLocked();
    }

    private void setShiftKeyGraphics(boolean newShiftState) {
        if (mShiftState.isShiftLocked()) {
            return;
        }
        for (final Key key : mShiftKeys) {
            final int attrId = newShiftState
                    ? R.styleable.Keyboard_iconShiftKeyShifted
                    : R.styleable.Keyboard_iconShiftKey;
            key.setIcon(mIconsSet.getIconByAttrId(attrId));
        }
    }

    // TODO: Remove this method.
    void setShifted(boolean newShiftState) {
        setShiftKeyGraphics(newShiftState);
        mShiftState.setShifted(newShiftState);
    }

    // TODO: Move this method to KeyboardId.
    public boolean isShiftedOrShiftLocked() {
        return mShiftState.isShiftedOrShiftLocked();
    }

    // TODO: Remove this method
    void setAutomaticTemporaryUpperCase() {
        setShiftKeyGraphics(true);
        mShiftState.setAutomaticTemporaryUpperCase();
    }

    // TODO: Move this method to KeyboardId.
    public boolean isManualTemporaryUpperCase() {
        return mShiftState.isManualTemporaryUpperCase();
    }

    // TODO: Remove this method.
    public String adjustLabelCase(String label) {
        if (mId.isAlphabetKeyboard() && isShiftedOrShiftLocked() && !TextUtils.isEmpty(label)
                && label.length() < 3 && Character.isLowerCase(label.charAt(0))) {
            return label.toUpperCase(mId.mLocale);
        }
        return label;
    }

    public static boolean isLetterCode(int code) {
        return code >= MINIMUM_LETTER_CODE;
    }

    public static class Params {
        public KeyboardId mId;
        public int mThemeId;

        /** Total height and width of the keyboard, including the paddings and keys */
        public int mOccupiedHeight;
        public int mOccupiedWidth;

        /** Base height and width of the keyboard used to calculate rows' or keys' heights and
         *  widths
         */
        public int mBaseHeight;
        public int mBaseWidth;

        public int mTopPadding;
        public int mBottomPadding;
        public int mHorizontalEdgesPadding;
        public int mHorizontalCenterPadding;

        public int mDefaultRowHeight;
        public int mDefaultKeyWidth;
        public int mHorizontalGap;
        public int mVerticalGap;

        public boolean mIsRtlKeyboard;
        public int mMoreKeysTemplate;
        public int mMaxMiniKeyboardColumn;

        public int GRID_WIDTH;
        public int GRID_HEIGHT;

        public final Set<Key> mKeys = new HashSet<Key>();
        public final Set<Key> mShiftKeys = new HashSet<Key>();
        public final Set<Key> mShiftLockKeys = new HashSet<Key>();
        public final KeyboardIconsSet mIconsSet = new KeyboardIconsSet();

        public int mMostCommonKeyHeight = 0;
        public int mMostCommonKeyWidth = 0;

        public final TouchPositionCorrection mTouchPositionCorrection =
                new TouchPositionCorrection();

        public static class TouchPositionCorrection {
            private static final int TOUCH_POSITION_CORRECTION_RECORD_SIZE = 3;

            public boolean mEnabled;
            public float[] mXs;
            public float[] mYs;
            public float[] mRadii;

            public void load(String[] data) {
                final int dataLength = data.length;
                if (dataLength % TOUCH_POSITION_CORRECTION_RECORD_SIZE != 0) {
                    if (LatinImeLogger.sDBG)
                        throw new RuntimeException(
                                "the size of touch position correction data is invalid");
                    return;
                }

                final int length = dataLength / TOUCH_POSITION_CORRECTION_RECORD_SIZE;
                mXs = new float[length];
                mYs = new float[length];
                mRadii = new float[length];
                try {
                    for (int i = 0; i < dataLength; ++i) {
                        final int type = i % TOUCH_POSITION_CORRECTION_RECORD_SIZE;
                        final int index = i / TOUCH_POSITION_CORRECTION_RECORD_SIZE;
                        final float value = Float.parseFloat(data[i]);
                        if (type == 0) {
                            mXs[index] = value;
                        } else if (type == 1) {
                            mYs[index] = value;
                        } else {
                            mRadii[index] = value;
                        }
                    }
                } catch (NumberFormatException e) {
                    if (LatinImeLogger.sDBG) {
                        throw new RuntimeException(
                                "the number format for touch position correction data is invalid");
                    }
                    mXs = null;
                    mYs = null;
                    mRadii = null;
                }
            }

            public void setEnabled(boolean enabled) {
                mEnabled = enabled;
            }

            public boolean isValid() {
                return mEnabled && mXs != null && mYs != null && mRadii != null
                    && mXs.length > 0 && mYs.length > 0 && mRadii.length > 0;
            }
        }

        protected void clearKeys() {
            mKeys.clear();
            mShiftKeys.clear();
            mShiftLockKeys.clear();
            clearHistogram();
        }

        public void onAddKey(Key key) {
            mKeys.add(key);
            updateHistogram(key);
            if (key.mCode == Keyboard.CODE_SHIFT) {
                mShiftKeys.add(key);
                if (key.isSticky()) {
                    mShiftLockKeys.add(key);
                }
            }
        }

        private int mMaxHeightCount = 0;
        private int mMaxWidthCount = 0;
        private final Map<Integer, Integer> mHeightHistogram = new HashMap<Integer, Integer>();
        private final Map<Integer, Integer> mWidthHistogram = new HashMap<Integer, Integer>();

        private void clearHistogram() {
            mMostCommonKeyHeight = 0;
            mMaxHeightCount = 0;
            mHeightHistogram.clear();

            mMaxWidthCount = 0;
            mMostCommonKeyWidth = 0;
            mWidthHistogram.clear();
        }

        private static int updateHistogramCounter(Map<Integer, Integer> histogram, Integer key) {
            final int count = (histogram.containsKey(key) ? histogram.get(key) : 0) + 1;
            histogram.put(key, count);
            return count;
        }

        private void updateHistogram(Key key) {
            final Integer height = key.mHeight + key.mVerticalGap;
            final int heightCount = updateHistogramCounter(mHeightHistogram, height);
            if (heightCount > mMaxHeightCount) {
                mMaxHeightCount = heightCount;
                mMostCommonKeyHeight = height;
            }

            final Integer width = key.mWidth + key.mHorizontalGap;
            final int widthCount = updateHistogramCounter(mWidthHistogram, width);
            if (widthCount > mMaxWidthCount) {
                mMaxWidthCount = widthCount;
                mMostCommonKeyWidth = width;
            }
        }
    }

    /**
     * Returns the array of the keys that are closest to the given point.
     * @param x the x-coordinate of the point
     * @param y the y-coordinate of the point
     * @return the array of the nearest keys to the given point. If the given
     * point is out of range, then an array of size zero is returned.
     */
    public Key[] getNearestKeys(int x, int y) {
        // Avoid dead pixels at edges of the keyboard
        final int adjustedX = Math.max(0, Math.min(x, mOccupiedWidth - 1));
        final int adjustedY = Math.max(0, Math.min(y, mOccupiedHeight - 1));
        return mProximityInfo.getNearestKeys(adjustedX, adjustedY);
    }

    public static String printableCode(int code) {
        switch (code) {
        case CODE_SHIFT: return "shift";
        case CODE_SWITCH_ALPHA_SYMBOL: return "symbol";
        case CODE_CAPSLOCK: return "capslock";
        case CODE_OUTPUT_TEXT: return "text";
        case CODE_DELETE: return "delete";
        case CODE_SHORTCUT: return "shortcut";
        case CODE_UNSPECIFIED: return "unspec";
        default:
            if (code <= 0) Log.w(TAG, "Unknown non-positive key code=" + code);
            if (code < CODE_SPACE) return String.format("'\\u%02x'", code);
            if (code < 0x100) return String.format("'%c'", code);
            return String.format("'\\u%04x'", code);
        }
    }

    public static String toThemeName(int themeId) {
        // This should be aligned with theme-*.xml resource files' themeId attribute.
        switch (themeId) {
        case 0: return "Basic";
        case 1: return "BasicHighContrast";
        case 5: return "IceCreamSandwich";
        case 6: return "Stone";
        case 7: return "StoneBold";
        case 8: return "GingerBread";
        default: return null;
        }
    }

    /**
     * Keyboard Building helper.
     *
     * This class parses Keyboard XML file and eventually build a Keyboard.
     * The Keyboard XML file looks like:
     * <pre>
     *   &gt;!-- xml/keyboard.xml --&lt;
     *   &gt;Keyboard keyboard_attributes*&lt;
     *     &gt;!-- Keyboard Content --&lt;
     *     &gt;Row row_attributes*&lt;
     *       &gt;!-- Row Content --&lt;
     *       &gt;Key key_attributes* /&lt;
     *       &gt;Spacer horizontalGap="0.2in" /&lt;
     *       &gt;include keyboardLayout="@xml/other_keys"&lt;
     *       ...
     *     &gt;/Row&lt;
     *     &gt;include keyboardLayout="@xml/other_rows"&lt;
     *     ...
     *   &gt;/Keyboard&lt;
     * </pre>
     * The XML file which is included in other file must have &gt;merge&lt; as root element,
     * such as:
     * <pre>
     *   &gt;!-- xml/other_keys.xml --&lt;
     *   &gt;merge&lt;
     *     &gt;Key key_attributes* /&lt;
     *     ...
     *   &gt;/merge&lt;
     * </pre>
     * and
     * <pre>
     *   &gt;!-- xml/other_rows.xml --&lt;
     *   &gt;merge&lt;
     *     &gt;Row row_attributes*&lt;
     *       &gt;Key key_attributes* /&lt;
     *     &gt;/Row&lt;
     *     ...
     *   &gt;/merge&lt;
     * </pre>
     * You can also use switch-case-default tags to select Rows and Keys.
     * <pre>
     *   &gt;switch&lt;
     *     &gt;case case_attribute*&lt;
     *       &gt;!-- Any valid tags at switch position --&lt;
     *     &gt;/case&lt;
     *     ...
     *     &gt;default&lt;
     *       &gt;!-- Any valid tags at switch position --&lt;
     *     &gt;/default&lt;
     *   &gt;/switch&lt;
     * </pre>
     * You can declare Key style and specify styles within Key tags.
     * <pre>
     *     &gt;switch&lt;
     *       &gt;case mode="email"&lt;
     *         &gt;key-style styleName="f1-key" parentStyle="modifier-key"
     *           keyLabel=".com"
     *         /&lt;
     *       &gt;/case&lt;
     *       &gt;case mode="url"&lt;
     *         &gt;key-style styleName="f1-key" parentStyle="modifier-key"
     *           keyLabel="http://"
     *         /&lt;
     *       &gt;/case&lt;
     *     &gt;/switch&lt;
     *     ...
     *     &gt;Key keyStyle="shift-key" ... /&lt;
     * </pre>
     */

    public static class Builder<KP extends Params> {
        private static final String TAG = Builder.class.getSimpleName();
        private static final boolean DEBUG = false;

        // Keyboard XML Tags
        private static final String TAG_KEYBOARD = "Keyboard";
        private static final String TAG_ROW = "Row";
        private static final String TAG_KEY = "Key";
        private static final String TAG_SPACER = "Spacer";
        private static final String TAG_INCLUDE = "include";
        private static final String TAG_MERGE = "merge";
        private static final String TAG_SWITCH = "switch";
        private static final String TAG_CASE = "case";
        private static final String TAG_DEFAULT = "default";
        public static final String TAG_KEY_STYLE = "key-style";

        private static final int DEFAULT_KEYBOARD_COLUMNS = 10;
        private static final int DEFAULT_KEYBOARD_ROWS = 4;

        protected final KP mParams;
        protected final Context mContext;
        protected final Resources mResources;
        private final DisplayMetrics mDisplayMetrics;

        private int mCurrentY = 0;
        private Row mCurrentRow = null;
        private boolean mLeftEdge;
        private boolean mTopEdge;
        private Key mRightEdgeKey = null;
        private final KeyStyles mKeyStyles = new KeyStyles();

        /**
         * Container for keys in the keyboard. All keys in a row are at the same Y-coordinate.
         * Some of the key size defaults can be overridden per row from what the {@link Keyboard}
         * defines.
         */
        public static class Row {
            // keyWidth enum constants
            private static final int KEYWIDTH_NOT_ENUM = 0;
            private static final int KEYWIDTH_FILL_RIGHT = -1;
            private static final int KEYWIDTH_FILL_BOTH = -2;

            private final Params mParams;
            /** Default width of a key in this row. */
            public final float mDefaultKeyWidth;
            /** Default height of a key in this row. */
            public final int mRowHeight;

            private final int mCurrentY;
            // Will be updated by {@link Key}'s constructor.
            private float mCurrentX;

            public Row(Resources res, Params params, XmlPullParser parser, int y) {
                mParams = params;
                TypedArray keyboardAttr = res.obtainAttributes(Xml.asAttributeSet(parser),
                        R.styleable.Keyboard);
                mRowHeight = (int)Builder.getDimensionOrFraction(keyboardAttr,
                        R.styleable.Keyboard_rowHeight,
                        params.mBaseHeight, params.mDefaultRowHeight);
                keyboardAttr.recycle();
                TypedArray keyAttr = res.obtainAttributes(Xml.asAttributeSet(parser),
                        R.styleable.Keyboard_Key);
                mDefaultKeyWidth = Builder.getDimensionOrFraction(keyAttr,
                        R.styleable.Keyboard_Key_keyWidth,
                        params.mBaseWidth, params.mDefaultKeyWidth);
                keyAttr.recycle();

                mCurrentY = y;
                mCurrentX = 0.0f;
            }

            public void setXPos(float keyXPos) {
                mCurrentX = keyXPos;
            }

            public void advanceXPos(float width) {
                mCurrentX += width;
            }

            public int getKeyY() {
                return mCurrentY;
            }

            public float getKeyX(TypedArray keyAttr) {
                final int widthType = Builder.getEnumValue(keyAttr,
                        R.styleable.Keyboard_Key_keyWidth, KEYWIDTH_NOT_ENUM);
                if (widthType == KEYWIDTH_FILL_BOTH) {
                    // If keyWidth is fillBoth, the key width should start right after the nearest
                    // key on the left hand side.
                    return mCurrentX;
                }

                final int keyboardRightEdge = mParams.mOccupiedWidth
                        - mParams.mHorizontalEdgesPadding;
                if (keyAttr.hasValue(R.styleable.Keyboard_Key_keyXPos)) {
                    final float keyXPos = Builder.getDimensionOrFraction(keyAttr,
                            R.styleable.Keyboard_Key_keyXPos, mParams.mBaseWidth, 0);
                    if (keyXPos < 0) {
                        // If keyXPos is negative, the actual x-coordinate will be
                        // keyboardWidth + keyXPos.
                        // keyXPos shouldn't be less than mCurrentX because drawable area for this
                        // key starts at mCurrentX. Or, this key will overlaps the adjacent key on
                        // its left hand side.
                        return Math.max(keyXPos + keyboardRightEdge, mCurrentX);
                    } else {
                        return keyXPos + mParams.mHorizontalEdgesPadding;
                    }
                }
                return mCurrentX;
            }

            public float getKeyWidth(TypedArray keyAttr, float keyXPos) {
                final int widthType = Builder.getEnumValue(keyAttr,
                        R.styleable.Keyboard_Key_keyWidth, KEYWIDTH_NOT_ENUM);
                switch (widthType) {
                case KEYWIDTH_FILL_RIGHT:
                case KEYWIDTH_FILL_BOTH:
                    final int keyboardRightEdge =
                            mParams.mOccupiedWidth - mParams.mHorizontalEdgesPadding;
                    // If keyWidth is fillRight, the actual key width will be determined to fill
                    // out the area up to the right edge of the keyboard.
                    // If keyWidth is fillBoth, the actual key width will be determined to fill out
                    // the area between the nearest key on the left hand side and the right edge of
                    // the keyboard.
                    return keyboardRightEdge - keyXPos;
                default: // KEYWIDTH_NOT_ENUM
                    return Builder.getDimensionOrFraction(keyAttr,
                            R.styleable.Keyboard_Key_keyWidth,
                            mParams.mBaseWidth, mDefaultKeyWidth);
                }
            }
        }

        public Builder(Context context, KP params) {
            mContext = context;
            final Resources res = context.getResources();
            mResources = res;
            mDisplayMetrics = res.getDisplayMetrics();

            mParams = params;

            setTouchPositionCorrectionData(context, params);

            params.GRID_WIDTH = res.getInteger(R.integer.config_keyboard_grid_width);
            params.GRID_HEIGHT = res.getInteger(R.integer.config_keyboard_grid_height);
        }

        private static void setTouchPositionCorrectionData(Context context, Params params) {
            final TypedArray a = context.obtainStyledAttributes(
                    null, R.styleable.Keyboard, R.attr.keyboardStyle, 0);
            params.mThemeId = a.getInt(R.styleable.Keyboard_themeId, 0);
            final int resourceId = a.getResourceId(
                    R.styleable.Keyboard_touchPositionCorrectionData, 0);
            a.recycle();
            if (resourceId == 0) {
                if (LatinImeLogger.sDBG)
                    Log.e(TAG, "touchPositionCorrectionData is not defined");
                return;
            }

            final String[] data = context.getResources().getStringArray(resourceId);
            params.mTouchPositionCorrection.load(data);
        }

        public Builder<KP> load(int xmlId, KeyboardId id) {
            mParams.mId = id;
            final XmlResourceParser parser = mResources.getXml(xmlId);
            try {
                parseKeyboard(parser);
            } catch (XmlPullParserException e) {
                Log.w(TAG, "keyboard XML parse error: " + e);
                throw new IllegalArgumentException(e);
            } catch (IOException e) {
                Log.w(TAG, "keyboard XML parse error: " + e);
                throw new RuntimeException(e);
            } finally {
                parser.close();
            }
            return this;
        }

        public void setTouchPositionCorrectionEnabled(boolean enabled) {
            mParams.mTouchPositionCorrection.setEnabled(enabled);
        }

        public Keyboard build() {
            return new Keyboard(mParams);
        }

        private void parseKeyboard(XmlPullParser parser)
                throws XmlPullParserException, IOException {
            if (DEBUG) Log.d(TAG, String.format("<%s> %s", TAG_KEYBOARD, mParams.mId));
            int event;
            while ((event = parser.next()) != XmlPullParser.END_DOCUMENT) {
                if (event == XmlPullParser.START_TAG) {
                    final String tag = parser.getName();
                    if (TAG_KEYBOARD.equals(tag)) {
                        parseKeyboardAttributes(parser);
                        startKeyboard();
                        parseKeyboardContent(parser, false);
                        break;
                    } else {
                        throw new XmlParseUtils.IllegalStartTag(parser, TAG_KEYBOARD);
                    }
                }
            }
        }

        private void parseKeyboardAttributes(XmlPullParser parser) {
            final int displayWidth = mDisplayMetrics.widthPixels;
            final TypedArray keyboardAttr = mContext.obtainStyledAttributes(
                    Xml.asAttributeSet(parser), R.styleable.Keyboard, R.attr.keyboardStyle,
                    R.style.Keyboard);
            final TypedArray keyAttr = mResources.obtainAttributes(Xml.asAttributeSet(parser),
                    R.styleable.Keyboard_Key);
            try {
                final int displayHeight = mDisplayMetrics.heightPixels;
                final int keyboardHeight = (int)keyboardAttr.getDimension(
                        R.styleable.Keyboard_keyboardHeight, displayHeight / 2);
                final int maxKeyboardHeight = (int)getDimensionOrFraction(keyboardAttr,
                        R.styleable.Keyboard_maxKeyboardHeight, displayHeight, displayHeight / 2);
                int minKeyboardHeight = (int)getDimensionOrFraction(keyboardAttr,
                        R.styleable.Keyboard_minKeyboardHeight, displayHeight, displayHeight / 2);
                if (minKeyboardHeight < 0) {
                    // Specified fraction was negative, so it should be calculated against display
                    // width.
                    minKeyboardHeight = -(int)getDimensionOrFraction(keyboardAttr,
                            R.styleable.Keyboard_minKeyboardHeight, displayWidth, displayWidth / 2);
                }
                final Params params = mParams;
                // Keyboard height will not exceed maxKeyboardHeight and will not be less than
                // minKeyboardHeight.
                params.mOccupiedHeight = Math.max(
                        Math.min(keyboardHeight, maxKeyboardHeight), minKeyboardHeight);
                params.mOccupiedWidth = params.mId.mWidth;
                params.mTopPadding = (int)getDimensionOrFraction(keyboardAttr,
                        R.styleable.Keyboard_keyboardTopPadding, params.mOccupiedHeight, 0);
                params.mBottomPadding = (int)getDimensionOrFraction(keyboardAttr,
                        R.styleable.Keyboard_keyboardBottomPadding, params.mOccupiedHeight, 0);
                params.mHorizontalEdgesPadding = (int)getDimensionOrFraction(keyboardAttr,
                        R.styleable.Keyboard_keyboardHorizontalEdgesPadding,
                        mParams.mOccupiedWidth, 0);

                params.mBaseWidth = params.mOccupiedWidth - params.mHorizontalEdgesPadding * 2
                        - params.mHorizontalCenterPadding;
                params.mDefaultKeyWidth = (int)getDimensionOrFraction(keyAttr,
                        R.styleable.Keyboard_Key_keyWidth, params.mBaseWidth,
                        params.mBaseWidth / DEFAULT_KEYBOARD_COLUMNS);
                params.mHorizontalGap = (int)getDimensionOrFraction(keyboardAttr,
                        R.styleable.Keyboard_horizontalGap, params.mBaseWidth, 0);
                params.mVerticalGap = (int)getDimensionOrFraction(keyboardAttr,
                        R.styleable.Keyboard_verticalGap, params.mOccupiedHeight, 0);
                params.mBaseHeight = params.mOccupiedHeight - params.mTopPadding
                        - params.mBottomPadding + params.mVerticalGap;
                params.mDefaultRowHeight = (int)getDimensionOrFraction(keyboardAttr,
                        R.styleable.Keyboard_rowHeight, params.mBaseHeight,
                        params.mBaseHeight / DEFAULT_KEYBOARD_ROWS);

                params.mIsRtlKeyboard = keyboardAttr.getBoolean(
                        R.styleable.Keyboard_isRtlKeyboard, false);
                params.mMoreKeysTemplate = keyboardAttr.getResourceId(
                        R.styleable.Keyboard_moreKeysTemplate, 0);
                params.mMaxMiniKeyboardColumn = keyAttr.getInt(
                        R.styleable.Keyboard_Key_maxMoreKeysColumn, 5);

                params.mIconsSet.loadIcons(keyboardAttr);
            } finally {
                keyAttr.recycle();
                keyboardAttr.recycle();
            }
        }

        private void parseKeyboardContent(XmlPullParser parser, boolean skip)
                throws XmlPullParserException, IOException {
            int event;
            while ((event = parser.next()) != XmlPullParser.END_DOCUMENT) {
                if (event == XmlPullParser.START_TAG) {
                    final String tag = parser.getName();
                    if (TAG_ROW.equals(tag)) {
                        Row row = parseRowAttributes(parser);
                        if (DEBUG) Log.d(TAG, String.format("<%s>", TAG_ROW));
                        if (!skip)
                            startRow(row);
                        parseRowContent(parser, row, skip);
                    } else if (TAG_INCLUDE.equals(tag)) {
                        parseIncludeKeyboardContent(parser, skip);
                    } else if (TAG_SWITCH.equals(tag)) {
                        parseSwitchKeyboardContent(parser, skip);
                    } else if (TAG_KEY_STYLE.equals(tag)) {
                        parseKeyStyle(parser, skip);
                    } else {
                        throw new XmlParseUtils.IllegalStartTag(parser, TAG_ROW);
                    }
                } else if (event == XmlPullParser.END_TAG) {
                    final String tag = parser.getName();
                    if (TAG_KEYBOARD.equals(tag)) {
                        endKeyboard();
                        break;
                    } else if (TAG_CASE.equals(tag) || TAG_DEFAULT.equals(tag)
                            || TAG_MERGE.equals(tag)) {
                        if (DEBUG) Log.d(TAG, String.format("</%s>", tag));
                        break;
                    } else if (TAG_KEY_STYLE.equals(tag)) {
                        continue;
                    } else {
                        throw new XmlParseUtils.IllegalEndTag(parser, TAG_ROW);
                    }
                }
            }
        }

        private Row parseRowAttributes(XmlPullParser parser) throws XmlPullParserException {
            final TypedArray a = mResources.obtainAttributes(Xml.asAttributeSet(parser),
                    R.styleable.Keyboard);
            try {
                if (a.hasValue(R.styleable.Keyboard_horizontalGap))
                    throw new XmlParseUtils.IllegalAttribute(parser, "horizontalGap");
                if (a.hasValue(R.styleable.Keyboard_verticalGap))
                    throw new XmlParseUtils.IllegalAttribute(parser, "verticalGap");
                return new Row(mResources, mParams, parser, mCurrentY);
            } finally {
                a.recycle();
            }
        }

        private void parseRowContent(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            int event;
            while ((event = parser.next()) != XmlPullParser.END_DOCUMENT) {
                if (event == XmlPullParser.START_TAG) {
                    final String tag = parser.getName();
                    if (TAG_KEY.equals(tag)) {
                        parseKey(parser, row, skip);
                    } else if (TAG_SPACER.equals(tag)) {
                        parseSpacer(parser, row, skip);
                    } else if (TAG_INCLUDE.equals(tag)) {
                        parseIncludeRowContent(parser, row, skip);
                    } else if (TAG_SWITCH.equals(tag)) {
                        parseSwitchRowContent(parser, row, skip);
                    } else if (TAG_KEY_STYLE.equals(tag)) {
                        parseKeyStyle(parser, skip);
                    } else {
                        throw new XmlParseUtils.IllegalStartTag(parser, TAG_KEY);
                    }
                } else if (event == XmlPullParser.END_TAG) {
                    final String tag = parser.getName();
                    if (TAG_ROW.equals(tag)) {
                        if (DEBUG) Log.d(TAG, String.format("</%s>", TAG_ROW));
                        if (!skip)
                            endRow(row);
                        break;
                    } else if (TAG_CASE.equals(tag) || TAG_DEFAULT.equals(tag)
                            || TAG_MERGE.equals(tag)) {
                        if (DEBUG) Log.d(TAG, String.format("</%s>", tag));
                        break;
                    } else if (TAG_KEY_STYLE.equals(tag)) {
                        continue;
                    } else {
                        throw new XmlParseUtils.IllegalEndTag(parser, TAG_KEY);
                    }
                }
            }
        }

        private void parseKey(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            if (skip) {
                XmlParseUtils.checkEndTag(TAG_KEY, parser);
            } else {
                final Key key = new Key(mResources, mParams, row, parser, mKeyStyles);
                if (DEBUG) Log.d(TAG, String.format("<%s%s keyLabel=%s code=%d moreKeys=%s />",
                        TAG_KEY, (key.isEnabled() ? "" : " disabled"), key.mLabel, key.mCode,
                        Arrays.toString(key.mMoreKeys)));
                XmlParseUtils.checkEndTag(TAG_KEY, parser);
                endKey(key);
            }
        }

        private void parseSpacer(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            if (skip) {
                XmlParseUtils.checkEndTag(TAG_SPACER, parser);
            } else {
                final Key.Spacer spacer = new Key.Spacer(
                        mResources, mParams, row, parser, mKeyStyles);
                if (DEBUG) Log.d(TAG, String.format("<%s />", TAG_SPACER));
                XmlParseUtils.checkEndTag(TAG_SPACER, parser);
                endKey(spacer);
            }
        }

        private void parseIncludeKeyboardContent(XmlPullParser parser, boolean skip)
                throws XmlPullParserException, IOException {
            parseIncludeInternal(parser, null, skip);
        }

        private void parseIncludeRowContent(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            parseIncludeInternal(parser, row, skip);
        }

        private void parseIncludeInternal(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            if (skip) {
                XmlParseUtils.checkEndTag(TAG_INCLUDE, parser);
            } else {
                final TypedArray a = mResources.obtainAttributes(Xml.asAttributeSet(parser),
                        R.styleable.Keyboard_Include);
                int keyboardLayout = 0;
                try {
                    XmlParseUtils.checkAttributeExists(a,
                            R.styleable.Keyboard_Include_keyboardLayout, "keyboardLayout",
                            TAG_INCLUDE, parser);
                    keyboardLayout = a.getResourceId(
                            R.styleable.Keyboard_Include_keyboardLayout, 0);
                } finally {
                    a.recycle();
                }

                XmlParseUtils.checkEndTag(TAG_INCLUDE, parser);
                if (DEBUG) Log.d(TAG, String.format("<%s keyboardLayout=%s />",
                        TAG_INCLUDE, mResources.getResourceEntryName(keyboardLayout)));
                final XmlResourceParser parserForInclude = mResources.getXml(keyboardLayout);
                try {
                    parseMerge(parserForInclude, row, skip);
                } finally {
                    parserForInclude.close();
                }
            }
        }

        private void parseMerge(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            int event;
            while ((event = parser.next()) != XmlPullParser.END_DOCUMENT) {
                if (event == XmlPullParser.START_TAG) {
                    final String tag = parser.getName();
                    if (TAG_MERGE.equals(tag)) {
                        if (row == null) {
                            parseKeyboardContent(parser, skip);
                        } else {
                            parseRowContent(parser, row, skip);
                        }
                        break;
                    } else {
                        throw new XmlParseUtils.ParseException(
                                "Included keyboard layout must have <merge> root element", parser);
                    }
                }
            }
        }

        private void parseSwitchKeyboardContent(XmlPullParser parser, boolean skip)
                throws XmlPullParserException, IOException {
            parseSwitchInternal(parser, null, skip);
        }

        private void parseSwitchRowContent(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            parseSwitchInternal(parser, row, skip);
        }

        private void parseSwitchInternal(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            if (DEBUG) Log.d(TAG, String.format("<%s> %s", TAG_SWITCH, mParams.mId));
            boolean selected = false;
            int event;
            while ((event = parser.next()) != XmlPullParser.END_DOCUMENT) {
                if (event == XmlPullParser.START_TAG) {
                    final String tag = parser.getName();
                    if (TAG_CASE.equals(tag)) {
                        selected |= parseCase(parser, row, selected ? true : skip);
                    } else if (TAG_DEFAULT.equals(tag)) {
                        selected |= parseDefault(parser, row, selected ? true : skip);
                    } else {
                        throw new XmlParseUtils.IllegalStartTag(parser, TAG_KEY);
                    }
                } else if (event == XmlPullParser.END_TAG) {
                    final String tag = parser.getName();
                    if (TAG_SWITCH.equals(tag)) {
                        if (DEBUG) Log.d(TAG, String.format("</%s>", TAG_SWITCH));
                        break;
                    } else {
                        throw new XmlParseUtils.IllegalEndTag(parser, TAG_KEY);
                    }
                }
            }
        }

        private boolean parseCase(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            final boolean selected = parseCaseCondition(parser);
            if (row == null) {
                // Processing Rows.
                parseKeyboardContent(parser, selected ? skip : true);
            } else {
                // Processing Keys.
                parseRowContent(parser, row, selected ? skip : true);
            }
            return selected;
        }

        private boolean parseCaseCondition(XmlPullParser parser) {
            final KeyboardId id = mParams.mId;
            if (id == null)
                return true;

            final TypedArray a = mResources.obtainAttributes(Xml.asAttributeSet(parser),
                    R.styleable.Keyboard_Case);
            try {
                final boolean keyboardSetElementMatched = matchTypedValue(a,
                        R.styleable.Keyboard_Case_keyboardSetElement, id.mElementId,
                        KeyboardId.elementIdToName(id.mElementId));
                final boolean modeMatched = matchTypedValue(a,
                        R.styleable.Keyboard_Case_mode, id.mMode, KeyboardId.modeName(id.mMode));
                final boolean navigateActionMatched = matchBoolean(a,
                        R.styleable.Keyboard_Case_navigateAction, id.navigateAction());
                final boolean passwordInputMatched = matchBoolean(a,
                        R.styleable.Keyboard_Case_passwordInput, id.passwordInput());
                final boolean hasSettingsKeyMatched = matchBoolean(a,
                        R.styleable.Keyboard_Case_hasSettingsKey, id.hasSettingsKey());
                final boolean f2KeyModeMatched = matchInteger(a,
                        R.styleable.Keyboard_Case_f2KeyMode, id.f2KeyMode());
                final boolean clobberSettingsKeyMatched = matchBoolean(a,
                        R.styleable.Keyboard_Case_clobberSettingsKey, id.mClobberSettingsKey);
                final boolean shortcutKeyEnabledMatched = matchBoolean(a,
                        R.styleable.Keyboard_Case_shortcutKeyEnabled, id.mShortcutKeyEnabled);
                final boolean hasShortcutKeyMatched = matchBoolean(a,
                        R.styleable.Keyboard_Case_hasShortcutKey, id.mHasShortcutKey);
                // As noted at {@link KeyboardId} class, we are interested only in enum value
                // masked by {@link android.view.inputmethod.EditorInfo#IME_MASK_ACTION} and
                // {@link android.view.inputmethod.EditorInfo#IME_FLAG_NO_ENTER_ACTION}. So matching
                // this attribute with id.mImeOptions as integer value is enough for our purpose.
                final boolean imeActionMatched = matchInteger(a,
                        R.styleable.Keyboard_Case_imeAction, id.imeAction());
                final boolean localeCodeMatched = matchString(a,
                        R.styleable.Keyboard_Case_localeCode, id.mLocale.toString());
                final boolean languageCodeMatched = matchString(a,
                        R.styleable.Keyboard_Case_languageCode, id.mLocale.getLanguage());
                final boolean countryCodeMatched = matchString(a,
                        R.styleable.Keyboard_Case_countryCode, id.mLocale.getCountry());
                final boolean selected = keyboardSetElementMatched && modeMatched
                        && navigateActionMatched && passwordInputMatched && hasSettingsKeyMatched
                        && f2KeyModeMatched && clobberSettingsKeyMatched
                        && shortcutKeyEnabledMatched && hasShortcutKeyMatched && imeActionMatched
                        && localeCodeMatched && languageCodeMatched && countryCodeMatched;

                if (DEBUG) Log.d(TAG, String.format("<%s%s%s%s%s%s%s%s%s%s%s%s%s%s> %s", TAG_CASE,
                        textAttr(a.getString(R.styleable.Keyboard_Case_keyboardSetElement),
                                "keyboardSetElement"),
                        textAttr(a.getString(R.styleable.Keyboard_Case_mode), "mode"),
                        booleanAttr(a, R.styleable.Keyboard_Case_navigateAction, "navigateAction"),
                        booleanAttr(a, R.styleable.Keyboard_Case_passwordInput, "passwordInput"),
                        booleanAttr(a, R.styleable.Keyboard_Case_hasSettingsKey, "hasSettingsKey"),
                        textAttr(KeyboardId.f2KeyModeName(
                                a.getInt(R.styleable.Keyboard_Case_f2KeyMode, -1)), "f2KeyMode"),
                        booleanAttr(a, R.styleable.Keyboard_Case_clobberSettingsKey,
                                "clobberSettingsKey"),
                        booleanAttr(a, R.styleable.Keyboard_Case_shortcutKeyEnabled,
                                "shortcutKeyEnabled"),
                        booleanAttr(a, R.styleable.Keyboard_Case_hasShortcutKey, "hasShortcutKey"),
                        textAttr(EditorInfoCompatUtils.imeOptionsName(
                                a.getInt(R.styleable.Keyboard_Case_imeAction, -1)), "imeAction"),
                        textAttr(a.getString(R.styleable.Keyboard_Case_localeCode), "localeCode"),
                        textAttr(a.getString(R.styleable.Keyboard_Case_languageCode),
                                "languageCode"),
                        textAttr(a.getString(R.styleable.Keyboard_Case_countryCode), "countryCode"),
                        Boolean.toString(selected)));

                return selected;
            } finally {
                a.recycle();
            }
        }

        private static boolean matchInteger(TypedArray a, int index, int value) {
            // If <case> does not have "index" attribute, that means this <case> is wild-card for
            // the attribute.
            return !a.hasValue(index) || a.getInt(index, 0) == value;
        }

        private static boolean matchBoolean(TypedArray a, int index, boolean value) {
            // If <case> does not have "index" attribute, that means this <case> is wild-card for
            // the attribute.
            return !a.hasValue(index) || a.getBoolean(index, false) == value;
        }

        private static boolean matchString(TypedArray a, int index, String value) {
            // If <case> does not have "index" attribute, that means this <case> is wild-card for
            // the attribute.
            return !a.hasValue(index)
                    || stringArrayContains(a.getString(index).split("\\|"), value);
        }

        private static boolean matchTypedValue(TypedArray a, int index, int intValue,
                String strValue) {
            // If <case> does not have "index" attribute, that means this <case> is wild-card for
            // the attribute.
            final TypedValue v = a.peekValue(index);
            if (v == null)
                return true;

            if (isIntegerValue(v)) {
                return intValue == a.getInt(index, 0);
            } else if (isStringValue(v)) {
                return stringArrayContains(a.getString(index).split("\\|"), strValue);
            }
            return false;
        }

        private static boolean stringArrayContains(String[] array, String value) {
            for (final String elem : array) {
                if (elem.equals(value))
                    return true;
            }
            return false;
        }

        private boolean parseDefault(XmlPullParser parser, Row row, boolean skip)
                throws XmlPullParserException, IOException {
            if (DEBUG) Log.d(TAG, String.format("<%s>", TAG_DEFAULT));
            if (row == null) {
                parseKeyboardContent(parser, skip);
            } else {
                parseRowContent(parser, row, skip);
            }
            return true;
        }

        private void parseKeyStyle(XmlPullParser parser, boolean skip)
                throws XmlPullParserException {
            TypedArray keyStyleAttr = mResources.obtainAttributes(Xml.asAttributeSet(parser),
                    R.styleable.Keyboard_KeyStyle);
            TypedArray keyAttrs = mResources.obtainAttributes(Xml.asAttributeSet(parser),
                    R.styleable.Keyboard_Key);
            try {
                if (!keyStyleAttr.hasValue(R.styleable.Keyboard_KeyStyle_styleName))
                    throw new XmlParseUtils.ParseException("<" + TAG_KEY_STYLE
                            + "/> needs styleName attribute", parser);
                if (!skip)
                    mKeyStyles.parseKeyStyleAttributes(keyStyleAttr, keyAttrs, parser);
            } finally {
                keyStyleAttr.recycle();
                keyAttrs.recycle();
            }
        }

        private void startKeyboard() {
            mCurrentY += mParams.mTopPadding;
            mTopEdge = true;
        }

        private void startRow(Row row) {
            addEdgeSpace(mParams.mHorizontalEdgesPadding, row);
            mCurrentRow = row;
            mLeftEdge = true;
            mRightEdgeKey = null;
        }

        private void endRow(Row row) {
            if (mCurrentRow == null)
                throw new InflateException("orphant end row tag");
            if (mRightEdgeKey != null) {
                mRightEdgeKey.markAsRightEdge(mParams);
                mRightEdgeKey = null;
            }
            addEdgeSpace(mParams.mHorizontalEdgesPadding, row);
            mCurrentY += row.mRowHeight;
            mCurrentRow = null;
            mTopEdge = false;
        }

        private void endKey(Key key) {
            mParams.onAddKey(key);
            if (mLeftEdge) {
                key.markAsLeftEdge(mParams);
                mLeftEdge = false;
            }
            if (mTopEdge) {
                key.markAsTopEdge(mParams);
            }
            mRightEdgeKey = key;
        }

        private void endKeyboard() {
            // nothing to do here.
        }

        private void addEdgeSpace(float width, Row row) {
            row.advanceXPos(width);
            mLeftEdge = false;
            mRightEdgeKey = null;
        }

        public static float getDimensionOrFraction(TypedArray a, int index, int base,
                float defValue) {
            final TypedValue value = a.peekValue(index);
            if (value == null)
                return defValue;
            if (isFractionValue(value)) {
                return a.getFraction(index, base, base, defValue);
            } else if (isDimensionValue(value)) {
                return a.getDimension(index, defValue);
            }
            return defValue;
        }

        public static int getEnumValue(TypedArray a, int index, int defValue) {
            final TypedValue value = a.peekValue(index);
            if (value == null)
                return defValue;
            if (isIntegerValue(value)) {
                return a.getInt(index, defValue);
            }
            return defValue;
        }

        private static boolean isFractionValue(TypedValue v) {
            return v.type == TypedValue.TYPE_FRACTION;
        }

        private static boolean isDimensionValue(TypedValue v) {
            return v.type == TypedValue.TYPE_DIMENSION;
        }

        private static boolean isIntegerValue(TypedValue v) {
            return v.type >= TypedValue.TYPE_FIRST_INT && v.type <= TypedValue.TYPE_LAST_INT;
        }

        private static boolean isStringValue(TypedValue v) {
            return v.type == TypedValue.TYPE_STRING;
        }

        private static String textAttr(String value, String name) {
            return value != null ? String.format(" %s=%s", name, value) : "";
        }

        private static String booleanAttr(TypedArray a, int index, String name) {
            return a.hasValue(index)
                    ? String.format(" %s=%s", name, a.getBoolean(index, false)) : "";
        }
    }
}