handler----隔3秒打印一次

package com.example;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class handler extends Activity {
    /** Called when the activity is first created. */
 private Button startButton=null;
 private Button endButton=null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        startButton = (Button)findViewById(R.id.startButton);
        startButton.setOnClickListener(new StartButtonClickListener());
        endButton = (Button)findViewById(R.id.endButton);
        endButton.setOnClickListener(new EndButtonClickListener());
    }
    class StartButtonClickListener implements OnClickListener{

  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub
   handler.post(updateThread);
  }
    }
    class EndButtonClickListener implements OnClickListener{

  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub
   handler.removeCallbacks(updateThread);
  }
     
    }
    Handler handler = new Handler();
    Runnable updateThread = new Runnable(){
     
     @Override
     public void run(){
      System.out.println("updateThread");
         handler.postDelayed(updateThread,3000);
     }
    };
}

 

 

main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
 <Button
    android:id="@+id/startButton"
    android:text="startButton"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>
    <Button
    android:id="@+id/endButton"
    android:text="endButton"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>
</LinearLayout>