在子线程更新UI组件

1.配合使用handle对象

2.使用 runOnUiThread() 方法

写惯java的人可能会认为Timer的使用应该如下：

程序功能很简单：10秒后，SetTitle为“hear me?”，然后，实际上这样做是不行的，这跟Android的线程安全有关！

 package com.ray.test;

 import java.util.Timer;
 import java.util.TimerTask;

 import android.app.Activity;
 import android.os.Bundle;

 public class JavaTimer extends Activity {

     Timer timer = new Timer();
     TimerTask task = new TimerTask(){

         public void run() {
             setTitle("hear me?");
         }

     };
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         timer.schedule(task, 10000);
     }
 }

 

但实际上的用法应该通过配合Handler来实现timer功能的！

package com.ray.test; import java.util.Timer; import java.util.TimerTask; import android.app.Activity; import android.os.Bundle; import android.os.Handler; import android.os.Message; public class TestTimer extends Activity { Timer timer = new Timer(); Handler handler = new Handler(){ public void handleMessage(Message msg) { switch (msg.what) { case 1: setTitle("hear me?"); break; } super.handleMessage(msg); } }; TimerTask task = new TimerTask(){ public void run() { Message message = new Message(); message.what = 1; handler.sendMessage(message); } }; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); timer.schedule(task, 10000); } }   package com.ray.test; import java.util.Timer; import java.util.TimerTask; import android.app.Activity; import android.os.Bundle; import android.os.Handler; import android.os.Message; public class TestTimer extends Activity { Timer timer = new Timer(); TimerTask task = new TimerTask(){ public void run() { runOnUiThread(new Runnable(){ @Override public void run() { setTitle("hear me?"); }}); } }; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); timer.schedule(task, 10000); } }  这样也可以执行UI的动作