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！