TimerTask 更新UI线程

今天在犯了一个愚蠢的错误，TimerTask中更新UI界面了，难怪半天没反应。

 

在网上搜了一篇Timer更新UI的帖子转过来。

 

错误写法：

package com.test; import java.util.Timer; import java.util.TimerTask; import android.app.Activity; import android.os.Bundle; public class TestTimer_Wrong 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); } }

 

TimerTask 里面直接做UI更新，没有在UIThread里面。与Java的EDT线程，是同一概念。

正确写法一　：　交由UI Thread处理

 

import java.util.Timer; import java.util.TimerTask; import android.app.Activity; import android.os.Bundle; 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); } }

 

正确写法二　：由Handler处理UI　更新。

package com.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); } }