关于键盘触发事件和屏幕触发事件的问题

当在自定义View或者做游戏的时候，我们常常会用到键盘触发事件和屏幕触发事件！在自定义的View里的键盘触发事件（比如：onKeyDown(int keyCode, KeyEvent event)）和屏幕触发事件（onTouchEvent(MotionEvent event)）和activity里的键盘触发事件（比如：onKeyDown(int keyCode, KeyEvent event)）和屏幕触发事件（onTouchEvent(MotionEvent event)）是怎么样交互的呢？是怎样的一个运行原理呢？下面来看看：

1、屏幕触发事件：哪个activity或者视图，控件在最上层就最先触发这个控件里的屏幕触发事件，返回值如果是默认或者false就会一层一层的往下传递！如果返回值是true,则在执行完动作之后不会往下传递！

2、键盘触发事件：这个原理和屏幕触发事件差不多，但是不同的时，在没有设置控件处于焦点时，一般按键盘里的按键触发的是activity里的键盘触发事件（比如：onKeyDown(int keyCode, KeyEvent event)）。

下面来举个例子：

比如在做游戏的时候，我们经常自定义视图，我们一般都喜欢和使用触发本视图（GameView）里的键盘触发事件和屏幕触发事件，但是比如：onKeyDown(int keyCode, KeyEvent event）)，一般我们按键盘的时候直接触发的是activity里的键盘触发事件，怎样让它直接触发（GameView）里的键盘触发事件呢?

第一种方法：

例子1：

View Code

  1 package net.loonggg.project;
  2 
  3 import android.app.Activity;
  4 import android.os.Bundle;
  5 import android.view.KeyEvent;
  6 import android.view.MotionEvent;
  7 
  8 public class MainActivity extends Activity {
  9     private GameView gameView;
 10 
 11     @Override
 12     public void onCreate(Bundle savedInstanceState) {
 13         super.onCreate(savedInstanceState);
 14         gameView = new GameView(this);
 15         setContentView(gameView);
 16     }
 17 
 18     @Override
 19     public boolean onKeyDown(int keyCode, KeyEvent event) {
 20         System.out.println("MainActivity:" + " keyCode:" + keyCode + " evnet:"
 21                 + event);
 22         return super.onKeyDown(keyCode, event);
 23     }
 24 
 25     @Override
 26     public boolean onTouchEvent(MotionEvent event) {
 27         System.out.println("MainActivity:" + "  event:" + event + " x:"
 28                 + event.getX() + " y:" + event.getY());
 29         return super.onTouchEvent(event);
 30     }
 31 }
 32 
 33 
 34 
 35 
 36 package net.loonggg.project;
 37 
 38 import android.content.Context;
 39 import android.graphics.Canvas;
 40 import android.graphics.Color;
 41 import android.graphics.Paint;
 42 import android.view.KeyEvent;
 43 import android.view.MotionEvent;
 44 import android.view.View;
 45 
 46 public class GameView extends View {
 47     private Paint paint;
 48     private int pointX;
 49     private int pointY;
 50 
 51     public GameView(Context context) {
 52         super(context);
 53         // 设置GameView获得焦点
 54         this.setFocusable(true);
 55         paint = new Paint();
 56         paint.setColor(Color.YELLOW);
 57         Thread t = new Thread(new MyThread());
 58         t.start();
 59     }
 60 
 61     @Override
 62     protected void onDraw(Canvas canvas) {
 63         super.onDraw(canvas);
 64         canvas.drawCircle(pointX, pointY, 15, paint);
 65     }
 66 
 67     class MyThread implements Runnable {
 68 
 69         @Override
 70         public void run() {
 71             while (true) {
 72                 try {
 73                     Thread.sleep(3000);
 74                     pointY = pointY + 10;
 75                     pointX = pointX + 10;
 76                     if (pointX > 200) {
 77                         break;
 78                     }
 79                 } catch (InterruptedException e) {
 80                     e.printStackTrace();
 81                 }
 82 
 83                 GameView.this.postInvalidate();
 84             }
 85         }
 86 
 87     }
 88 
 89     @Override
 90     public boolean onKeyDown(int keyCode, KeyEvent event) {
 91         System.out.println("GameView:" + " keyCode:" + keyCode + " evnet:"
 92                 + event);
 93         //此事件不会传播出去
 94         return true;
 95     }
 96 
 97     @Override
 98     public boolean onTouchEvent(MotionEvent event) {
 99         System.out.println("GameView:" + "  event:" + event + " x:"
100                 + event.getX() + " y:" + event.getY());
101         //此事件不会传播出去
102         return true;
103     }
104 
105 }

第二种方法：

View Code

  1 package net.loonggg.project;
  2 
  3 import android.app.Activity;
  4 import android.os.Bundle;
  5 import android.view.KeyEvent;
  6 import android.view.MotionEvent;
  7 
  8 public class MainActivity extends Activity {
  9     private GameView gameView;
 10 
 11     @Override
 12     public void onCreate(Bundle savedInstanceState) {
 13         super.onCreate(savedInstanceState);
 14         gameView = new GameView(this);
 15         setContentView(gameView);
 16     }
 17 
 18     @Override
 19     public boolean onKeyDown(int keyCode, KeyEvent event) {
 20         System.out.println("MainActivity:" + " keyCode:" + keyCode + " evnet:"
 21                 + event);
 22         //把事件传递给gameView
 23         gameView.onKeyDown(keyCode, event);
 24         return super.onKeyDown(keyCode, event);
 25     }
 26 
 27     @Override
 28     public boolean onTouchEvent(MotionEvent event) {
 29         System.out.println("MainActivity:" + "  event:" + event + " x:"
 30                 + event.getX() + " y:" + event.getY());
 31         //把事件传递给gameView
 32         gameView.onTouchEvent(event);
 33         return super.onTouchEvent(event);
 34     }
 35 }
 36 
 37 
 38 
 39 package net.loonggg.project;
 40 
 41 import android.content.Context;
 42 import android.graphics.Canvas;
 43 import android.graphics.Color;
 44 import android.graphics.Paint;
 45 import android.view.KeyEvent;
 46 import android.view.MotionEvent;
 47 import android.view.View;
 48 
 49 public class GameView extends View {
 50     private Paint paint;
 51     private int pointX;
 52     private int pointY;
 53 
 54     public GameView(Context context) {
 55         super(context);
 56         paint = new Paint();
 57         paint.setColor(Color.YELLOW);
 58         Thread t = new Thread(new MyThread());
 59         t.start();
 60     }
 61 
 62     @Override
 63     protected void onDraw(Canvas canvas) {
 64         super.onDraw(canvas);
 65         canvas.drawCircle(pointX, pointY, 15, paint);
 66     }
 67 
 68     class MyThread implements Runnable {
 69 
 70         @Override
 71         public void run() {
 72             while (true) {
 73                 try {
 74                     Thread.sleep(3000);
 75                     pointY = pointY + 10;
 76                     pointX = pointX + 10;
 77                     if (pointX > 200) {
 78                         break;
 79                     }
 80                 } catch (InterruptedException e) {
 81                     e.printStackTrace();
 82                 }
 83 
 84                 GameView.this.postInvalidate();
 85             }
 86         }
 87 
 88     }
 89 
 90     @Override
 91     public boolean onKeyDown(int keyCode, KeyEvent event) {
 92         System.out.println("GameView:" + " keyCode:" + keyCode + " evnet:"
 93                 + event);
 94         return super.onKeyDown(keyCode, event);
 95     }
 96 
 97     @Override
 98     public boolean onTouchEvent(MotionEvent event) {
 99         System.out.println("GameView:" + "  event:" + event + " x:"
100                 + event.getX() + " y:" + event.getY());
101         return super.onTouchEvent(event);
102     }
103 
104 }

在这里，推荐使用第二种方法，因为第一种方法有的模拟器不能够使用！