两个小时精通Android开发之按键映射篇


作者：孙东风 2010-01-07（转载务必注明出处）

笔者的上篇文章《html" target=_blank>两个小时精通Android开发》中讲解了利用Android的接口规范开发J2ME的Wrap包，从而解决了J2ME程序无法运行在Android平台上的技术难题，但是Android平台和J2ME另一个重要的不同点就是按键响应接口，如何让J2ME程序的按键响应可以无缝的移植到Android上呢？答案也是Wrap包。
 
笔者这里通过按键映射把Android平台的键盘码转换成J2ME平台的键盘码，或者把Android平台的触摸事件通过代理传递给J2ME中相应的接口。
 
首先，需要在Android平台的GameCanvas里进行如下定义：
 
public class GameCanvas extends Screen {
     public static final int UP = 1;
     public static final int DOWN = 6;
     public static final int LEFT = 2;
     public static final int RIGHT = 5;
     public static final int FIRE = 8;
     
     public static final int GAME_A = 9;
     public static final int GAME_B = 10;
     public static final int GAME_C = 11;
     public static final int GAME_D = 12;
     
     public static final int KEY_NUM0 = 48;
     public static final int KEY_NUM1 = 49;
     public static final int KEY_NUM2 = 50;
     public static final int KEY_NUM3 = 51;
     public static final int KEY_NUM4 = 52;
     public static final int KEY_NUM5 = 53;
     public static final int KEY_NUM6 = 54;
     public static final int KEY_NUM7 = 55;
     public static final int KEY_NUM8 = 56;
     public static final int KEY_NUM9 = 57;
     public static final int KEY_STAR = 42;
     public static final int KEY_POUND = 35;
}
 
当然，为了适配J2ME里的接口笔者还定义如下的接口：
 
     protected abstract void keyRepeated(int keyCode);
     protected abstract void keyPressed(int keyCode);
     protected abstract void keyReleased(int keyCode);
     protected abstract void pointerPressed(int x, int y);
     protected abstract void pointerReleased(int x, int y)
     protected abstract void pointerDragged(int x, int y);
 
笔者在上面定义的都是J2ME的视图类Canvas里的按键响应接口，这里需要做的工作就是把Android里的按键进行映射转换成J2ME里的标准键值后传递给这些接口，并由继承自GameCanvas的界面类进行实现，完全和J2ME里一样了，基本不用修改任何代码。
 
键值映射的代码如下：
 
     public int keyActual = 0;
     public int keyAction = 0;
     
     public void keyPreparse(int keyCode,KeyEvent e)
     {
         if(keyCode == KeyEvent.KEYCODE_0)
         {
              keyActual = GameCanvas.KEY_NUM0;
         }else if(keyCode == KeyEvent.KEYCODE_1)
         {
              keyActual = GameCanvas.KEY_NUM1;
         }else if(keyCode == KeyEvent.KEYCODE_2)
         {
              keyActual = GameCanvas.KEY_NUM2;
         }else if(keyCode == KeyEvent.KEYCODE_3)
         {
              keyActual = GameCanvas.KEY_NUM3;
         }else if(keyCode == KeyEvent.KEYCODE_4)
         {
              keyActual = GameCanvas.KEY_NUM4;
         }else if(keyCode == KeyEvent.KEYCODE_5)
         {
              keyActual = GameCanvas.KEY_NUM5;
         }else if(keyCode == KeyEvent.KEYCODE_6)
         {
              keyActual = GameCanvas.KEY_NUM6;
         }else if(keyCode == KeyEvent.KEYCODE_7)
         {
              keyActual = GameCanvas.KEY_NUM7;
         }else if(keyCode == KeyEvent.KEYCODE_8)
         {
              keyActual = GameCanvas.KEY_NUM8;
         }else if(keyCode == KeyEvent.KEYCODE_9)
         {
              keyActual = GameCanvas.KEY_NUM9;
         }else if(keyCode == KeyEvent.KEYCODE_POUND)
         {
              keyActual = GameCanvas.KEY_POUND;
         }else if(keyCode == KeyEvent.KEYCODE_STAR)
         {
              keyActual = GameCanvas.KEY_STAR;
         }else if(keyCode == KeyEvent.KEYCODE_DPAD_UP)
         {
              keyActual = GameCanvas.UP;
              keyAction = GameCanvas.UP;
         }else if(keyCode == KeyEvent.KEYCODE_DPAD_DOWN)
         {
              keyActual = GameCanvas.DOWN;
              keyAction = GameCanvas.DOWN;
         }else if(keyCode == KeyEvent.KEYCODE_DPAD_LEFT)
         {
              keyActual = GameCanvas.LEFT;
              keyAction = GameCanvas.LEFT;
         }else if(keyCode == KeyEvent.KE

补充：移动开发 , Android ,