2011-2-14 | Android Handler

最新推荐文章于 2025-12-05 09:24:48 发布

最新推荐文章于 2025-12-05 09:24:48 发布 · 69 阅读

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2010-2-14

关键词：Android Handler

如下的代码实现一个Iphone 上的一个通过按backspace键后，数字过多消除的按钮事件。事件的原理如下，事件要的效果是这样的，当长按消除按钮后，数字会慢慢消除，当消除5个字符后继续消除的话消除速度会增快。通过这份代码可以帮助我们较好的初识Handler的工作机制。

 
   package com.william.handlertest;
   
   import android.app.Activity;
   
   import android.os.Bundle;
   
   import android.os.Handler;
   
   import android.os.Message;
   
   import android.view.MotionEvent;
   
   import android.view.View;
   
   import android.widget.Button;
   
   import android.widget.EditText;
   
   import android.widget.TextView;
   
   public 
   class HandlerTest 
   extends Activity 
   implements Runnable{
   
   private EditText content 
   = null;
   
   private Button backspace 
   = null;
   
   private 
   boolean isStop 
   = false;
   
   private Handler mHandler 
   = null;
   
   private 
   class BackspaceOnTouchListener 
   implements Button.OnTouchListener{
   
@Override
   
   public 
   boolean onTouch(View v, MotionEvent event) {
   
   switch(event.getAction()){
   
   case MotionEvent.ACTION_DOWN
   :
   
isStop 
   = true;
   
mHandler 
   = getHandler(content);
   
   new Thread(HandlerTest.
   this).start();
   
   break;
   
   case MotionEvent.ACTION_UP
   :
   
isStop 
   = false;
   
   break;
   
   default
   :
   
   break;
   
}
   
   return false;
   
}
   
}
   
@Override
   
   public 
   void onCreate(Bundle savedInstanceState) {
   
   super.onCreate(savedInstanceState);
   
setContentView(R.layout.main);
   
content 
   = (EditText) findViewById(R.id.content);
   
content.setCursorVisible(false);
   
backspace 
   = (Button) findViewById(R.id.backspace);
   
backspace.setOnTouchListener(
   new BackspaceOnTouchListener());
   
}
   
   private Handler getHandler(
   final TextView content){
   
   return 
   new Handler(){
   
@Override
   
   public 
   void handleMessage(Message msg) {
   
content.setText((String)msg.obj);
   
   super.handleMessage(msg);
   
}
   
};
   
}
   
@Override
   
   public 
   void run() {
   
   try{
   
   int i 
   = 
   0;
   
   do{
   
i
   ++;
   
Thread.sleep((i 
   > 
   5 
   ? 
   100 
   : 
   500));
   
String contentStr 
   = 
   this.content.getText().toString();
   
   if(contentStr.length()
   ==
   0){
   
   break;
   
}
   
contentStr 
   = contentStr.substring(
   0, contentStr.length()
   -
   1);
   
Message msg 
   = mHandler.obtainMessage();
   
msg.obj
   =contentStr;
   
msg.sendToTarget();
   
}
   while(isStop);
   
}
   catch(Exception e){
   
e.printStackTrace();
   
}
   
}
   
}