android --自定义数字软键盘的设计与实现（1）


		相信很多情况下我们看到过一些数字的输入，弹出来的并不是系统自带的键盘。这就是自定义的软键盘，软键盘的一个好处就是简单，操作方便。如何实现一个自定义的软键盘呢？？其实这个过程是比较简单的，只要把几个关键的原理搞明白了，你就会发现真的很简单，很方便！看一下效果图：
 

 
这篇博客主要介绍一下实现的相关原理，下一节就会把具体实现的步骤和大家分享一下！
 
实现软键盘主要用到了系统的两个类Keyboard和KeyboardView:
 
Keyboard类源码的介绍是： Listener for virtual keyboard events.即用于监听虚拟键盘。
 
至于Keyboard类的映射机制，这里就不需要说了，本人感觉也没必要了解的太深，这里要介绍一些他，在接下来需要的几个重要的内容。我们看一下他的源码：
 
package com.android.inputmethod.keyboard;
 
import android.util.Log;
import android.util.SparseArray;
import com.android.inputmethod.keyboard.internal.KeyVisualAttributes;
import com.android.inputmethod.keyboard.internal.KeyboardIconsSet;
import com.android.inputmethod.keyboard.internal.KeyboardParams;
import com.android.inputmethod.latin.CollectionUtils;
 
/**
 * 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>
 * <Keyboard
 *         latin:keyWidth="%10p"
 *         latin:keyHeight="50px"
 *         latin:horizontalGap="2px"
 *         latin:verticalGap="2px" >
 *     <Row latin:keyWidth="32px" >
 *         <Key latin:keyLabel="A" />
 *         ...
 *     </Row>
 *     ...
 * </Keyboard>
 * </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 = '"';
    public static final int CODE_QUESTION_MARK = '?';
    public static final int CODE_EXCLAMATION_MARK = '!';
    // 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 = '>';
    /** Special keys code. Must be negative.
     * These should be aligned with KeyboardCodesSet.ID_TO_NAME[],
     * KeyboardCodesSet.DEFAULT[] and KeyboardCodesSet.RTL[]
     */
    public static final int CODE_SHIFT = -1;
    public static final int CODE_SWITCH_ALPHA_SYMBOL = -2;
    public static final int CODE_OUTPUT_TEXT = -3;
    public static final int CODE_DELETE = -4;
    public static final int CODE_SETTINGS = -5;
    public static final int CODE_SHORTCUT = -6;
    public static final int CODE_ACTION_ENTER = -7;
    public static final int CODE_ACTION_NEXT = -8;
    public static final int CODE_ACTION_PREVIOUS = -9;
    public static final int CODE_LANGUAGE_SWITCH = -10;
    public static final int CODE_RESEARCH = -11;
    // Code value representing the code is not specified.
    public static final int CODE_UNSPECIFIED = -12;
    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;
 
    /** Per keyboard key visual parameters */
    public final KeyVisualAttributes mKeyVisualAttributes;
    public final int mMostCommonKeyHeight;
    public final int mMostCommonKeyWidth;
    /** More keys keyboard template */
    public final int mMoreKeysTemplate;
    /** Maximum column for more keys keyboard */
    public final int mMaxMoreKeysKeyboardColumn;
    /** Array of keys and icons in this keyboard */
    public final Key[] mKeys;
    public final Key[] mShiftKeys;
    public final Key[] mAltCodeKeysWhileTyping;
    public final KeyboardIconsSet mIconsSet;
    private final SparseArray<Key> mKeyCache = CollectionUtils.newSparseArray();
    private final ProximityInfo mProximityInfo;
    private final boolean mProximityCharsCorrectionEnabled;
    public Keyboard(final KeyboardParams params) {
    /// M: @{
        ProximityInfo tmp;
        /// @}
        mId = params.mId;
        mThemeId = params.mThemeId;
        mOccupiedHeight = params.mOccupiedHeight;
        mOccupiedWidth = params.mOccupiedWidth;
        mMostCommonKeyHeight = params.mMostCommonKeyHeight;
        mMostCommonKeyWidth = params.mMostCommonKeyWidth;
        mMoreKeysTemplate = params.mMoreKeysTemplate;
        mMaxMoreKeysKeyboardColumn = params.mMaxM

补充：移动开发 , Android ,