https://source.android.com/ 
/*
 * Copyright (C) 2007 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.view;

import android.hardware.input.InputManager;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.method.MetaKeyKeyListener;
import android.util.AndroidRuntimeException;
import android.util.SparseIntArray;

import java.text.Normalizer;


Describes the keys provided by a keyboard device and their associated labels.

/**
 * Describes the keys provided by a keyboard device and their associated labels.
 */
public class KeyCharacterMap implements Parcelable {
    
The id of the device's primary built in keyboard is always 0.

Deprecated:This constant should no longer be used because there is no guarantee that a device has a built-in keyboard that can be used for typing text. There might not be a built-in keyboard, the built-in keyboard might be a NUMERIC or SPECIAL_FUNCTION keyboard, or there might be multiple keyboards installed including external keyboards. When interpreting key presses received from the framework, applications should use the device id specified in the KeyEvent received. When synthesizing key presses for delivery elsewhere or when translating key presses from unknown keyboards, applications should use the special VIRTUAL_KEYBOARD device id.
/**
     * The id of the device's primary built in keyboard is always 0.
     *
     * @deprecated This constant should no longer be used because there is no
     * guarantee that a device has a built-in keyboard that can be used for
     * typing text.  There might not be a built-in keyboard, the built-in keyboard
     * might be a {@link #NUMERIC} or {@link #SPECIAL_FUNCTION} keyboard, or there
     * might be multiple keyboards installed including external keyboards.
     * When interpreting key presses received from the framework, applications should
     * use the device id specified in the {@link KeyEvent} received.
     * When synthesizing key presses for delivery elsewhere or when translating key presses
     * from unknown keyboards, applications should use the special {@link #VIRTUAL_KEYBOARD}
     * device id.
     */
    @Deprecated
    public static final int BUILT_IN_KEYBOARD = 0;

    
The id of a generic virtual keyboard with a full layout that can be used to synthesize key events. Typically used with getEvents. 
/**
     * The id of a generic virtual keyboard with a full layout that can be used to
     * synthesize key events.  Typically used with {@link #getEvents}.
     */
    public static final int VIRTUAL_KEYBOARD = -1;

    
A numeric (12-key) keyboard.


A numeric keyboard supports text entry using a multi-tap approach.
It may be necessary to tap a key multiple times to generate the desired letter
or symbol.


This type of keyboard is generally designed for thumb typing.



/**
     * A numeric (12-key) keyboard.
     * <p>
     * A numeric keyboard supports text entry using a multi-tap approach.
     * It may be necessary to tap a key multiple times to generate the desired letter
     * or symbol.
     * </p><p>
     * This type of keyboard is generally designed for thumb typing.
     * </p>
     */
    public static final int NUMERIC = 1;

    
A keyboard with all the letters, but with more than one letter per key.


This type of keyboard is generally designed for thumb typing.



/**
     * A keyboard with all the letters, but with more than one letter per key.
     * <p>
     * This type of keyboard is generally designed for thumb typing.
     * </p>
     */
    public static final int PREDICTIVE = 2;

    
A keyboard with all the letters, and maybe some numbers.

 An alphabetic keyboard supports text entry directly but may have a condensed layout with a small form factor. In contrast to a full keyboard, some symbols may only be accessible using special on-screen character pickers. In addition, to improve typing speed and accuracy, the framework provides special affordances for alphabetic keyboards such as auto-capitalization and toggled / locked shift and alt keys. 

This type of keyboard is generally designed for thumb typing.



/**
     * A keyboard with all the letters, and maybe some numbers.
     * <p>
     * An alphabetic keyboard supports text entry directly but may have a condensed
     * layout with a small form factor.  In contrast to a {@link #FULL full keyboard}, some
     * symbols may only be accessible using special on-screen character pickers.
     * In addition, to improve typing speed and accuracy, the framework provides
     * special affordances for alphabetic keyboards such as auto-capitalization
     * and toggled / locked shift and alt keys.
     * </p><p>
     * This type of keyboard is generally designed for thumb typing.
     * </p>
     */
    public static final int ALPHA = 3;

    
A full PC-style keyboard.


A full keyboard behaves like a PC keyboard.  All symbols are accessed directly
by pressing keys on the keyboard without on-screen support or affordances such
as auto-capitalization.


This type of keyboard is generally designed for full two hand typing.



/**
     * A full PC-style keyboard.
     * <p>
     * A full keyboard behaves like a PC keyboard.  All symbols are accessed directly
     * by pressing keys on the keyboard without on-screen support or affordances such
     * as auto-capitalization.
     * </p><p>
     * This type of keyboard is generally designed for full two hand typing.
     * </p>
     */
    public static final int FULL = 4;

    
A keyboard that is only used to control special functions rather than for typing.


A special function keyboard consists only of non-printing keys such as
HOME and POWER that are not actually used for typing.



/**
     * A keyboard that is only used to control special functions rather than for typing.
     * <p>
     * A special function keyboard consists only of non-printing keys such as
     * HOME and POWER that are not actually used for typing.
     * </p>
     */
    public static final int SPECIAL_FUNCTION = 5;

    
This private-use character is used to trigger Unicode character
input by hex digits.

/**
     * This private-use character is used to trigger Unicode character
     * input by hex digits.
     */
    public static final char HEX_INPUT = '\uEF00';

    
This private-use character is used to bring up a character picker for
miscellaneous symbols.

/**
     * This private-use character is used to bring up a character picker for
     * miscellaneous symbols.
     */
    public static final char PICKER_DIALOG_INPUT = '\uEF01';

    
Modifier keys may be chorded with character keys.

See Also:
/**
     * Modifier keys may be chorded with character keys.
     *
     * @see {@link #getModifierBehavior()} for more details.
     */
    public static final int MODIFIER_BEHAVIOR_CHORDED = 0;

    
Modifier keys may be chorded with character keys or they may toggle
into latched or locked states when pressed independently.

See Also:
/**
     * Modifier keys may be chorded with character keys or they may toggle
     * into latched or locked states when pressed independently.
     *
     * @see {@link #getModifierBehavior()} for more details.
     */
    public static final int MODIFIER_BEHAVIOR_CHORDED_OR_TOGGLED = 1;

    /*
     * This bit will be set in the return value of {@link #get(int, int)} if the
     * key is a "dead key."
     */
    public static final int COMBINING_ACCENT = 0x80000000;

    
Mask the return value from get(int, int) with this value to get a printable representation of the accent character of a "dead key." 
/**
     * Mask the return value from {@link #get(int, int)} with this value to get
     * a printable representation of the accent character of a "dead key."
     */
    public static final int COMBINING_ACCENT_MASK = 0x7FFFFFFF;

    /* Characters used to display placeholders for dead keys. */
    private static final int ACCENT_ACUTE = '\u00B4';
    private static final int ACCENT_BREVE = '\u02D8';
    private static final int ACCENT_CARON = '\u02C7';
    private static final int ACCENT_CEDILLA = '\u00B8';
    private static final int ACCENT_CIRCUMFLEX = '\u02C6';
    private static final int ACCENT_COMMA_ABOVE = '\u1FBD';
    private static final int ACCENT_COMMA_ABOVE_RIGHT = '\u02BC';
    private static final int ACCENT_DOT_ABOVE = '\u02D9';
    private static final int ACCENT_DOT_BELOW = '.'; // approximate
    private static final int ACCENT_DOUBLE_ACUTE = '\u02DD';
    private static final int ACCENT_GRAVE = '\u02CB';
    private static final int ACCENT_HOOK_ABOVE = '\u02C0';
    private static final int ACCENT_HORN = '\''; // approximate
    private static final int ACCENT_MACRON = '\u00AF';
    private static final int ACCENT_MACRON_BELOW = '\u02CD';
    private static final int ACCENT_OGONEK = '\u02DB';
    private static final int ACCENT_REVERSED_COMMA_ABOVE = '\u02BD';
    private static final int ACCENT_RING_ABOVE = '\u02DA';
    private static final int ACCENT_STROKE = '-'; // approximate
    private static final int ACCENT_TILDE = '\u02DC';
    private static final int ACCENT_TURNED_COMMA_ABOVE = '\u02BB';
    private static final int ACCENT_UMLAUT = '\u00A8';
    private static final int ACCENT_VERTICAL_LINE_ABOVE = '\u02C8';
    private static final int ACCENT_VERTICAL_LINE_BELOW = '\u02CC';

    /* Legacy dead key display characters used in previous versions of the API.
     * We still support these characters by mapping them to their non-legacy version. */
    private static final int ACCENT_GRAVE_LEGACY = '`';
    private static final int ACCENT_CIRCUMFLEX_LEGACY = '^';
    private static final int ACCENT_TILDE_LEGACY = '~';

    private static final int CHAR_SPACE = ' ';

    
Maps Unicode combining diacritical to display-form dead key.

/**
     * Maps Unicode combining diacritical to display-form dead key.
     */
    private static final SparseIntArray sCombiningToAccent = new SparseIntArray();
    private static final SparseIntArray sAccentToCombining = new SparseIntArray();
    static {
        addCombining('\u0300', ACCENT_GRAVE);
        addCombining('\u0301', ACCENT_ACUTE);
        addCombining('\u0302', ACCENT_CIRCUMFLEX);
        addCombining('\u0303', ACCENT_TILDE);
        addCombining('\u0304', ACCENT_MACRON);
        addCombining('\u0306', ACCENT_BREVE);
        addCombining('\u0307', ACCENT_DOT_ABOVE);
        addCombining('\u0308', ACCENT_UMLAUT);
        addCombining('\u0309', ACCENT_HOOK_ABOVE);
        addCombining('\u030A', ACCENT_RING_ABOVE);
        addCombining('\u030B', ACCENT_DOUBLE_ACUTE);
        addCombining('\u030C', ACCENT_CARON);
        addCombining('\u030D', ACCENT_VERTICAL_LINE_ABOVE);
        //addCombining('\u030E', ACCENT_DOUBLE_VERTICAL_LINE_ABOVE);
        //addCombining('\u030F', ACCENT_DOUBLE_GRAVE);
        //addCombining('\u0310', ACCENT_CANDRABINDU);
        //addCombining('\u0311', ACCENT_INVERTED_BREVE);
        addCombining('\u0312', ACCENT_TURNED_COMMA_ABOVE);
        addCombining('\u0313', ACCENT_COMMA_ABOVE);
        addCombining('\u0314', ACCENT_REVERSED_COMMA_ABOVE);
        addCombining('\u0315', ACCENT_COMMA_ABOVE_RIGHT);
        addCombining('\u031B', ACCENT_HORN);
        addCombining('\u0323', ACCENT_DOT_BELOW);
        //addCombining('\u0326', ACCENT_COMMA_BELOW);
        addCombining('\u0327', ACCENT_CEDILLA);
        addCombining('\u0328', ACCENT_OGONEK);
        addCombining('\u0329', ACCENT_VERTICAL_LINE_BELOW);
        addCombining('\u0331', ACCENT_MACRON_BELOW);
        addCombining('\u0335', ACCENT_STROKE);
        //addCombining('\u0342', ACCENT_PERISPOMENI);
        //addCombining('\u0344', ACCENT_DIALYTIKA_TONOS);
        //addCombining('\u0345', ACCENT_YPOGEGRAMMENI);

        // One-way mappings to equivalent preferred accents.
        sCombiningToAccent.append('\u0340', ACCENT_GRAVE);
        sCombiningToAccent.append('\u0341', ACCENT_ACUTE);
        sCombiningToAccent.append('\u0343', ACCENT_COMMA_ABOVE);

        // One-way legacy mappings to preserve compatibility with older applications.
        sAccentToCombining.append(ACCENT_GRAVE_LEGACY, '\u0300');
        sAccentToCombining.append(ACCENT_CIRCUMFLEX_LEGACY, '\u0302');
        sAccentToCombining.append(ACCENT_TILDE_LEGACY, '\u0303');
    }

    private static void addCombining(int combining, int accent) {
        sCombiningToAccent.append(combining, accent);
        sAccentToCombining.append(accent, combining);
    }

    
Maps combinations of (display-form) combining key and second character
to combined output character.
These mappings are derived from the Unicode NFC tables as needed.

/**
     * Maps combinations of (display-form) combining key and second character
     * to combined output character.
     * These mappings are derived from the Unicode NFC tables as needed.
     */
    private static final SparseIntArray sDeadKeyCache = new SparseIntArray();
    private static final StringBuilder sDeadKeyBuilder = new StringBuilder();
    static {
        // Non-standard decompositions.
        // Stroke modifier for Finnish multilingual keyboard and others.
        addDeadKey(ACCENT_STROKE, 'D', '\u0110');
        addDeadKey(ACCENT_STROKE, 'G', '\u01e4');
        addDeadKey(ACCENT_STROKE, 'H', '\u0126');
        addDeadKey(ACCENT_STROKE, 'I', '\u0197');
        addDeadKey(ACCENT_STROKE, 'L', '\u0141');
        addDeadKey(ACCENT_STROKE, 'O', '\u00d8');
        addDeadKey(ACCENT_STROKE, 'T', '\u0166');
        addDeadKey(ACCENT_STROKE, 'd', '\u0111');
        addDeadKey(ACCENT_STROKE, 'g', '\u01e5');
        addDeadKey(ACCENT_STROKE, 'h', '\u0127');
        addDeadKey(ACCENT_STROKE, 'i', '\u0268');
        addDeadKey(ACCENT_STROKE, 'l', '\u0142');
        addDeadKey(ACCENT_STROKE, 'o', '\u00f8');
        addDeadKey(ACCENT_STROKE, 't', '\u0167');
    }

    private static void addDeadKey(int accent, int c, int result) {
        final int combining = sAccentToCombining.get(accent);
        if (combining == 0) {
            throw new IllegalStateException("Invalid dead key declaration.");
        }
        final int combination = (combining << 16) | c;
        sDeadKeyCache.put(combination, result);
    }

    public static final Parcelable.Creator<KeyCharacterMap> CREATOR =
            new Parcelable.Creator<KeyCharacterMap>() {
        public KeyCharacterMap createFromParcel(Parcel in) {
            return new KeyCharacterMap(in);
        }
        public KeyCharacterMap[] newArray(int size) {
            return new KeyCharacterMap[size];
        }
    };

    private long mPtr;

    private static native long nativeReadFromParcel(Parcel in);
    private static native void nativeWriteToParcel(long ptr, Parcel out);
    private static native void nativeDispose(long ptr);

    private static native char nativeGetCharacter(long ptr, int keyCode, int metaState);
    private static native boolean nativeGetFallbackAction(long ptr, int keyCode, int metaState,
            FallbackAction outFallbackAction);
    private static native char nativeGetNumber(long ptr, int keyCode);
    private static native char nativeGetMatch(long ptr, int keyCode, char[] chars, int metaState);
    private static native char nativeGetDisplayLabel(long ptr, int keyCode);
    private static native int nativeGetKeyboardType(long ptr);
    private static native KeyEvent[] nativeGetEvents(long ptr, char[] chars);

    private KeyCharacterMap(Parcel in) {
        if (in == null) {
            throw new IllegalArgumentException("parcel must not be null");
        }
        mPtr = nativeReadFromParcel(in);
        if (mPtr == 0) {
            throw new RuntimeException("Could not read KeyCharacterMap from parcel.");
        }
    }

    // Called from native
    private KeyCharacterMap(long ptr) {
        mPtr = ptr;
    }

    @Override
    protected void finalize() throws Throwable {
        if (mPtr != 0) {
            nativeDispose(mPtr);
            mPtr = 0;
        }
    }

    
Loads the key character maps for the keyboard with the specified device id.

Params:
  • deviceId – The device id of the keyboard.
Throws:
  •  {@link UnavailableException} if the key character map
 – could not be loaded because it was malformed or the default key character map
is missing from the system.
Returns:The associated key character map.
/**
     * Loads the key character maps for the keyboard with the specified device id.
     *
     * @param deviceId The device id of the keyboard.
     * @return The associated key character map.
     * @throws {@link UnavailableException} if the key character map
     * could not be loaded because it was malformed or the default key character map
     * is missing from the system.
     */
    public static KeyCharacterMap load(int deviceId) {
        final InputManager im = InputManager.getInstance();
        InputDevice inputDevice = im.getInputDevice(deviceId);
        if (inputDevice == null) {
            inputDevice = im.getInputDevice(VIRTUAL_KEYBOARD);
            if (inputDevice == null) {
                throw new UnavailableException(
                        "Could not load key character map for device " + deviceId);
            }
        }
        return inputDevice.getKeyCharacterMap();
    }

    
Gets the Unicode character generated by the specified key and meta
key state combination.

 Returns the Unicode character that the specified key would produce when the specified meta bits (see MetaKeyKeyListener) were active. 

Returns 0 if the key is not one that is used to type Unicode
characters.

 If the return value has bit COMBINING_ACCENT set, the key is a "dead key" that should be combined with another to actually produce a character -- see getDeadChar -- after masking with COMBINING_ACCENT_MASK. 


Params:
  • keyCode – The key code.
  • metaState – The meta key modifier state.
Returns:The associated character or combining accent, or 0 if none.
/**
     * Gets the Unicode character generated by the specified key and meta
     * key state combination.
     * <p>
     * Returns the Unicode character that the specified key would produce
     * when the specified meta bits (see {@link MetaKeyKeyListener})
     * were active.
     * </p><p>
     * Returns 0 if the key is not one that is used to type Unicode
     * characters.
     * </p><p>
     * If the return value has bit {@link #COMBINING_ACCENT} set, the
     * key is a "dead key" that should be combined with another to
     * actually produce a character -- see {@link #getDeadChar} --
     * after masking with {@link #COMBINING_ACCENT_MASK}.
     * </p>
     *
     * @param keyCode The key code.
     * @param metaState The meta key modifier state.
     * @return The associated character or combining accent, or 0 if none.
     */
    public int get(int keyCode, int metaState) {
        metaState = KeyEvent.normalizeMetaState(metaState);
        char ch = nativeGetCharacter(mPtr, keyCode, metaState);

        int map = sCombiningToAccent.get(ch);
        if (map != 0) {
            return map | COMBINING_ACCENT;
        } else {
            return ch;
        }
    }

    
Gets the fallback action to perform if the application does not
handle the specified key.

 When an application does not handle a particular key, the system may translate the key to an alternate fallback key (specified in the fallback action) and dispatch it to the application. The event containing the fallback key is flagged with KeyEvent.FLAG_FALLBACK. 


Params:
  • keyCode – The key code.
  • metaState – The meta key modifier state.
Returns:The fallback action, or null if none.  Remember to recycle the fallback action.
@hide
/**
     * Gets the fallback action to perform if the application does not
     * handle the specified key.
     * <p>
     * When an application does not handle a particular key, the system may
     * translate the key to an alternate fallback key (specified in the
     * fallback action) and dispatch it to the application.
     * The event containing the fallback key is flagged
     * with {@link KeyEvent#FLAG_FALLBACK}.
     * </p>
     *
     * @param keyCode The key code.
     * @param metaState The meta key modifier state.
     * @return The fallback action, or null if none.  Remember to recycle the fallback action.
     *
     * @hide
     */
    public FallbackAction getFallbackAction(int keyCode, int metaState) {
        FallbackAction action = FallbackAction.obtain();
        metaState = KeyEvent.normalizeMetaState(metaState);
        if (nativeGetFallbackAction(mPtr, keyCode, metaState, action)) {
            action.metaState = KeyEvent.normalizeMetaState(action.metaState);
            return action;
        }
        action.recycle();
        return null;
    }

    
Gets the number or symbol associated with the key.


The character value is returned, not the numeric value.
If the key is not a number, but is a symbol, the symbol is retuned.


This method is intended to to support dial pads and other numeric or
symbolic entry on keyboards where certain keys serve dual function
as alphabetic and symbolic keys.  This method returns the number
or symbol associated with the key independent of whether the user
has pressed the required modifier.

 For example, on one particular keyboard the keys on the top QWERTY row generate numbers when ALT is pressed such that ALT-Q maps to '1'. So for that keyboard when getNumber is called with KeyEvent.KEYCODE_Q it returns '1' so that the user can type numbers without pressing ALT when it makes sense. 


Params:
  • keyCode – The key code.
Returns:The associated numeric or symbolic character, or 0 if none.
/**
     * Gets the number or symbol associated with the key.
     * <p>
     * The character value is returned, not the numeric value.
     * If the key is not a number, but is a symbol, the symbol is retuned.
     * </p><p>
     * This method is intended to to support dial pads and other numeric or
     * symbolic entry on keyboards where certain keys serve dual function
     * as alphabetic and symbolic keys.  This method returns the number
     * or symbol associated with the key independent of whether the user
     * has pressed the required modifier.
     * </p><p>
     * For example, on one particular keyboard the keys on the top QWERTY row generate
     * numbers when ALT is pressed such that ALT-Q maps to '1'.  So for that keyboard
     * when {@link #getNumber} is called with {@link KeyEvent#KEYCODE_Q} it returns '1'
     * so that the user can type numbers without pressing ALT when it makes sense.
     * </p>
     *
     * @param keyCode The key code.
     * @return The associated numeric or symbolic character, or 0 if none.
     */
    public char getNumber(int keyCode) {
        return nativeGetNumber(mPtr, keyCode);
    }

    
Gets the first character in the character array that can be generated
by the specified key code.

 This is a convenience function that returns the same value as getMatch(keyCode, chars, 0). 


Params:
  • keyCode – The keycode.
  • chars – The array of matching characters to consider.
Throws:
  •  {@link IllegalArgumentException} if the passed array of characters is null.
 – 
Returns:The matching associated character, or 0 if none.
/**
     * Gets the first character in the character array that can be generated
     * by the specified key code.
     * <p>
     * This is a convenience function that returns the same value as
     * {@link #getMatch(int,char[],int) getMatch(keyCode, chars, 0)}.
     * </p>
     *
     * @param keyCode The keycode.
     * @param chars The array of matching characters to consider.
     * @return The matching associated character, or 0 if none.
     * @throws {@link IllegalArgumentException} if the passed array of characters is null.
     */
    public char getMatch(int keyCode, char[] chars) {
        return getMatch(keyCode, chars, 0);
    }

    
Gets the first character in the character array that can be generated
by the specified key code.  If there are multiple choices, prefers
the one that would be generated with the specified meta key modifier state.

Params:
  • keyCode – The key code.
  • chars – The array of matching characters to consider.
  • metaState – The preferred meta key modifier state.
Throws:
  •  {@link IllegalArgumentException} if the passed array of characters is null.
 – 
Returns:The matching associated character, or 0 if none.
/**
     * Gets the first character in the character array that can be generated
     * by the specified key code.  If there are multiple choices, prefers
     * the one that would be generated with the specified meta key modifier state.
     *
     * @param keyCode The key code.
     * @param chars The array of matching characters to consider.
     * @param metaState The preferred meta key modifier state.
     * @return The matching associated character, or 0 if none.
     * @throws {@link IllegalArgumentException} if the passed array of characters is null.
     */
    public char getMatch(int keyCode, char[] chars, int metaState) {
        if (chars == null) {
            throw new IllegalArgumentException("chars must not be null.");
        }

        metaState = KeyEvent.normalizeMetaState(metaState);
        return nativeGetMatch(mPtr, keyCode, chars, metaState);
    }

    
Gets the primary character for this key.
In other words, the label that is physically printed on it.

Params:
  • keyCode – The key code.
Returns:The display label character, or 0 if none (eg. for non-printing keys).
/**
     * Gets the primary character for this key.
     * In other words, the label that is physically printed on it.
     *
     * @param keyCode The key code.
     * @return The display label character, or 0 if none (eg. for non-printing keys).
     */
    public char getDisplayLabel(int keyCode) {
        return nativeGetDisplayLabel(mPtr, keyCode);
    }

    
Get the character that is produced by combining the dead key producing accent
with the key producing character c.
For example, getDeadChar('`', 'e') returns è.
getDeadChar('^', ' ') returns '^' and getDeadChar('^', '^') returns '^'.

Params:
  • accent – The accent character.  eg. '`'
  • c – The basic character.
Returns:The combined character, or 0 if the characters cannot be combined.
/**
     * Get the character that is produced by combining the dead key producing accent
     * with the key producing character c.
     * For example, getDeadChar('`', 'e') returns &egrave;.
     * getDeadChar('^', ' ') returns '^' and getDeadChar('^', '^') returns '^'.
     *
     * @param accent The accent character.  eg. '`'
     * @param c The basic character.
     * @return The combined character, or 0 if the characters cannot be combined.
     */
    public static int getDeadChar(int accent, int c) {
        if (c == accent || CHAR_SPACE == c) {
            // The same dead character typed twice or a dead character followed by a
            // space should both produce the non-combining version of the combining char.
            // In this case we don't even need to compute the combining character.
            return accent;
        }

        int combining = sAccentToCombining.get(accent);
        if (combining == 0) {
            return 0;
        }

        final int combination = (combining << 16) | c;
        int combined;
        synchronized (sDeadKeyCache) {
            combined = sDeadKeyCache.get(combination, -1);
            if (combined == -1) {
                sDeadKeyBuilder.setLength(0);
                sDeadKeyBuilder.append((char)c);
                sDeadKeyBuilder.append((char)combining);
                String result = Normalizer.normalize(sDeadKeyBuilder, Normalizer.Form.NFC);
                combined = result.codePointCount(0, result.length()) == 1
                        ? result.codePointAt(0) : 0;
                sDeadKeyCache.put(combination, combined);
            }
        }
        return combined;
    }

    
Describes the character mappings associated with a key.

Deprecated:instead use KeyCharacterMap.getDisplayLabel(int), KeyCharacterMap.getNumber(int) and KeyCharacterMap.get(int, int).
/**
     * Describes the character mappings associated with a key.
     *
     * @deprecated instead use {@link KeyCharacterMap#getDisplayLabel(int)},
     * {@link KeyCharacterMap#getNumber(int)} and {@link KeyCharacterMap#get(int, int)}.
     */
    @Deprecated
    public static class KeyData {
        public static final int META_LENGTH = 4;

        
The display label (see getDisplayLabel). 
/**
         * The display label (see {@link #getDisplayLabel}).
         */
        public char displayLabel;
        
The "number" value (see getNumber). 
/**
         * The "number" value (see {@link #getNumber}).
         */
        public char number;
        
The character that will be generated in various meta states (the same ones used for get and defined as KeyEvent.META_SHIFT_ON and KeyEvent.META_ALT_ON). 

         
IndexValue

         
0no modifiers

         
1caps

         
2alt

         
3caps + alt

     


/**
         * The character that will be generated in various meta states
         * (the same ones used for {@link #get} and defined as
         * {@link KeyEvent#META_SHIFT_ON} and {@link KeyEvent#META_ALT_ON}).
         *      <table>
         *          <tr><th>Index</th><th align="left">Value</th></tr>
         *          <tr><td>0</td><td>no modifiers</td></tr>
         *          <tr><td>1</td><td>caps</td></tr>
         *          <tr><td>2</td><td>alt</td></tr>
         *          <tr><td>3</td><td>caps + alt</td></tr>
         *      </table>
         */
        public char[] meta = new char[META_LENGTH];
    }

    
Get the character conversion data for a given key code.

Params:
  • keyCode – The keyCode to query.
  • results – A KeyData instance that will be filled with the results.
Returns:True if the key was mapped.  If the key was not mapped, results is not modified.
Deprecated:instead use getDisplayLabel(int), getNumber(int) or get(int, int).
/**
     * Get the character conversion data for a given key code.
     *
     * @param keyCode The keyCode to query.
     * @param results A {@link KeyData} instance that will be filled with the results.
     * @return True if the key was mapped.  If the key was not mapped, results is not modified.
     *
     * @deprecated instead use {@link KeyCharacterMap#getDisplayLabel(int)},
     * {@link KeyCharacterMap#getNumber(int)} or {@link KeyCharacterMap#get(int, int)}.
     */
    @Deprecated
    public boolean getKeyData(int keyCode, KeyData results) {
        if (results.meta.length < KeyData.META_LENGTH) {
            throw new IndexOutOfBoundsException(
                    "results.meta.length must be >= " + KeyData.META_LENGTH);
        }

        char displayLabel = nativeGetDisplayLabel(mPtr, keyCode);
        if (displayLabel == 0) {
            return false;
        }

        results.displayLabel = displayLabel;
        results.number = nativeGetNumber(mPtr, keyCode);
        results.meta[0] = nativeGetCharacter(mPtr, keyCode, 0);
        results.meta[1] = nativeGetCharacter(mPtr, keyCode, KeyEvent.META_SHIFT_ON);
        results.meta[2] = nativeGetCharacter(mPtr, keyCode, KeyEvent.META_ALT_ON);
        results.meta[3] = nativeGetCharacter(mPtr, keyCode,
                KeyEvent.META_ALT_ON | KeyEvent.META_SHIFT_ON);
        return true;
    }

    
Get an array of KeyEvent objects that if put into the input stream
could plausibly generate the provided sequence of characters.  It is
not guaranteed that the sequence is the only way to generate these
events or that it is optimal.

 This function is primarily offered for instrumentation and testing purposes. It may fail to map characters to key codes. In particular, the key character map for the built-in keyboard device id may be empty. Consider using the key character map associated with the virtual keyboard device id instead. 
 For robust text entry, do not use this function. Instead construct a KeyEvent with action code KeyEvent.ACTION_MULTIPLE that contains the desired string using KeyEvent(long, String, int, int). 


Params:
  • chars – The sequence of characters to generate.
Throws:
  •  {@link IllegalArgumentException} if the passed array of characters is null.
 – 
Returns:An array of KeyEvent objects, or null if the given char array can not be generated using the current key character map.
/**
     * Get an array of KeyEvent objects that if put into the input stream
     * could plausibly generate the provided sequence of characters.  It is
     * not guaranteed that the sequence is the only way to generate these
     * events or that it is optimal.
     * <p>
     * This function is primarily offered for instrumentation and testing purposes.
     * It may fail to map characters to key codes.  In particular, the key character
     * map for the {@link #BUILT_IN_KEYBOARD built-in keyboard} device id may be empty.
     * Consider using the key character map associated with the
     * {@link #VIRTUAL_KEYBOARD virtual keyboard} device id instead.
     * </p><p>
     * For robust text entry, do not use this function.  Instead construct a
     * {@link KeyEvent} with action code {@link KeyEvent#ACTION_MULTIPLE} that contains
     * the desired string using {@link KeyEvent#KeyEvent(long, String, int, int)}.
     * </p>
     *
     * @param chars The sequence of characters to generate.
     * @return An array of {@link KeyEvent} objects, or null if the given char array
     *         can not be generated using the current key character map.
     * @throws {@link IllegalArgumentException} if the passed array of characters is null.
     */
    public KeyEvent[] getEvents(char[] chars) {
        if (chars == null) {
            throw new IllegalArgumentException("chars must not be null.");
        }
        return nativeGetEvents(mPtr, chars);
    }

    
Returns true if the specified key produces a glyph.

Params:
  • keyCode – The key code.
Returns:True if the key is a printing key.
/**
     * Returns true if the specified key produces a glyph.
     *
     * @param keyCode The key code.
     * @return True if the key is a printing key.
     */
    public boolean isPrintingKey(int keyCode) {
        int type = Character.getType(nativeGetDisplayLabel(mPtr, keyCode));

        switch (type)
        {
            case Character.SPACE_SEPARATOR:
            case Character.LINE_SEPARATOR:
            case Character.PARAGRAPH_SEPARATOR:
            case Character.CONTROL:
            case Character.FORMAT:
                return false;
            default:
                return true;
        }
    }

    
Gets the keyboard type. Returns NUMERIC, PREDICTIVE, ALPHA, FULL or SPECIAL_FUNCTION. 

Different keyboard types have different semantics.  Refer to the documentation
associated with the keyboard type constants for details.



Returns:The keyboard type.
/**
     * Gets the keyboard type.
     * Returns {@link #NUMERIC}, {@link #PREDICTIVE}, {@link #ALPHA}, {@link #FULL}
     * or {@link #SPECIAL_FUNCTION}.
     * <p>
     * Different keyboard types have different semantics.  Refer to the documentation
     * associated with the keyboard type constants for details.
     * </p>
     *
     * @return The keyboard type.
     */
    public int getKeyboardType() {
        return nativeGetKeyboardType(mPtr);
    }

    
Gets a constant that describes the behavior of this keyboard's modifier keys such as KeyEvent.KEYCODE_SHIFT_LEFT. 

Currently there are two behaviors that may be combined:



    

  • Chorded behavior: When the modifier key is pressed together with one or more
character keys, the keyboard inserts the modified keys and
then resets the modifier state when the modifier key is released.
    • 

  • Toggled behavior: When the modifier key is pressed and released on its own
it first toggles into a latched state.  When latched, the modifier will apply
to next character key that is pressed and will then reset itself to the initial state.
If the modifier is already latched and the modifier key is pressed and release on
its own again, then it toggles into a locked state.  When locked, the modifier will
apply to all subsequent character keys that are pressed until unlocked by pressing
the modifier key on its own one more time to reset it to the initial state.
Toggled behavior is useful for small profile keyboards designed for thumb typing.



 This function currently returns MODIFIER_BEHAVIOR_CHORDED when the keyboard type is FULL or SPECIAL_FUNCTION and MODIFIER_BEHAVIOR_CHORDED_OR_TOGGLED otherwise. In the future, the function may also take into account global keyboard accessibility settings, other user preferences, or new device capabilities. 


See Also:
Returns:The modifier behavior for this keyboard.
/**
     * Gets a constant that describes the behavior of this keyboard's modifier keys
     * such as {@link KeyEvent#KEYCODE_SHIFT_LEFT}.
     * <p>
     * Currently there are two behaviors that may be combined:
     * </p>
     * <ul>
     * <li>Chorded behavior: When the modifier key is pressed together with one or more
     * character keys, the keyboard inserts the modified keys and
     * then resets the modifier state when the modifier key is released.</li>
     * <li>Toggled behavior: When the modifier key is pressed and released on its own
     * it first toggles into a latched state.  When latched, the modifier will apply
     * to next character key that is pressed and will then reset itself to the initial state.
     * If the modifier is already latched and the modifier key is pressed and release on
     * its own again, then it toggles into a locked state.  When locked, the modifier will
     * apply to all subsequent character keys that are pressed until unlocked by pressing
     * the modifier key on its own one more time to reset it to the initial state.
     * Toggled behavior is useful for small profile keyboards designed for thumb typing.
     * </ul>
     * <p>
     * This function currently returns {@link #MODIFIER_BEHAVIOR_CHORDED} when the
     * {@link #getKeyboardType() keyboard type} is {@link #FULL} or {@link #SPECIAL_FUNCTION} and
     * {@link #MODIFIER_BEHAVIOR_CHORDED_OR_TOGGLED} otherwise.
     * In the future, the function may also take into account global keyboard
     * accessibility settings, other user preferences, or new device capabilities.
     * </p>
     *
     * @return The modifier behavior for this keyboard.
     *
     * @see #MODIFIER_BEHAVIOR_CHORDED
     * @see #MODIFIER_BEHAVIOR_CHORDED_OR_TOGGLED
     */
    public int getModifierBehavior() {
        switch (getKeyboardType()) {
            case FULL:
            case SPECIAL_FUNCTION:
                return MODIFIER_BEHAVIOR_CHORDED;
            default:
                return MODIFIER_BEHAVIOR_CHORDED_OR_TOGGLED;
        }
    }

    
Queries the framework about whether any physical keys exist on the
any keyboard attached to the device that are capable of producing the given key code.

Params:
  • keyCode – The key code to query.
Returns:True if at least one attached keyboard supports the specified key code.
/**
     * Queries the framework about whether any physical keys exist on the
     * any keyboard attached to the device that are capable of producing the given key code.
     *
     * @param keyCode The key code to query.
     * @return True if at least one attached keyboard supports the specified key code.
     */
    public static boolean deviceHasKey(int keyCode) {
        return InputManager.getInstance().deviceHasKeys(new int[] { keyCode })[0];
    }

    
Queries the framework about whether any physical keys exist on the
any keyboard attached to the device that are capable of producing the given
array of key codes.

Params:
  • keyCodes – The array of key codes to query.
Returns:A new array of the same size as the key codes array whose elements
are set to true if at least one attached keyboard supports the corresponding key code
at the same index in the key codes array.
/**
     * Queries the framework about whether any physical keys exist on the
     * any keyboard attached to the device that are capable of producing the given
     * array of key codes.
     *
     * @param keyCodes The array of key codes to query.
     * @return A new array of the same size as the key codes array whose elements
     * are set to true if at least one attached keyboard supports the corresponding key code
     * at the same index in the key codes array.
     */
    public static boolean[] deviceHasKeys(int[] keyCodes) {
        return InputManager.getInstance().deviceHasKeys(keyCodes);
    }

    @Override
    public void writeToParcel(Parcel out, int flags) {
        if (out == null) {
            throw new IllegalArgumentException("parcel must not be null");
        }
        nativeWriteToParcel(mPtr, out);
    }

    @Override
    public int describeContents() {
        return 0;
    }

    
Thrown by KeyCharacterMap.load when a key character map could not be loaded. 
/**
     * Thrown by {@link KeyCharacterMap#load} when a key character map could not be loaded.
     */
    public static class UnavailableException extends AndroidRuntimeException {
        public UnavailableException(String msg) {
            super(msg);
        }
    }

    
Specifies a substitute key code and meta state as a fallback action
for an unhandled key.

@hide
/**
     * Specifies a substitute key code and meta state as a fallback action
     * for an unhandled key.
     * @hide
     */
    public static final class FallbackAction {
        private static final int MAX_RECYCLED = 10;
        private static final Object sRecycleLock = new Object();
        private static FallbackAction sRecycleBin;
        private static int sRecycledCount;

        private FallbackAction next;

        public int keyCode;
        public int metaState;

        private FallbackAction() {
        }

        public static FallbackAction obtain() {
            final FallbackAction target;
            synchronized (sRecycleLock) {
                if (sRecycleBin == null) {
                    target = new FallbackAction();
                } else {
                    target = sRecycleBin;
                    sRecycleBin = target.next;
                    sRecycledCount--;
                    target.next = null;
                }
            }
            return target;
        }

        public void recycle() {
            synchronized (sRecycleLock) {
                if (sRecycledCount < MAX_RECYCLED) {
                    next = sRecycleBin;
                    sRecycleBin = this;
                    sRecycledCount += 1;
                } else {
                    next = null;
                }
            }
        }
    }
}