Android進行異步更新UI的四種方式

大家都知道由于性能要求，android要求只能在UI線程中更新UI，要想在其他線程中更新UI，我大致總結了4種方式，歡迎補充糾正：

1. 使用Handler消息傳遞機制；

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2. 使用AsyncTask異步任務；

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3. 使用runOnUiThread(action)方法；

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4. 使用Handler的post(Runnabel r)方法；

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   下面分別使用四種方式來更新一個TextView。

   1.使用Handler消息傳遞機制

   package com.example.runonuithreadtest;
   import android.app.Activity;
   import android.os.Bundle;
   import android.os.Handler;
   import android.widget.TextView;
   public class MainActivity extends Activity {
       private TextView tv;
       Handler handler = new Handler()
       {
           public void handleMessage(android.os.Message msg) {
               if(msg.what==0x123)
               {
                   tv.setText("更新后的TextView");
               }
           };
       };
       @Override
       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
           tv = (TextView) findViewById(R.id.tv);
           new MyThread().start();
       }
       class MyThread extends Thread
       {
           @Override
           public void run() {
               //延遲兩秒更新
               try {
                   Thread.sleep(2000);
               } catch (InterruptedException e) {
                   // TODO Auto-generated catch block
                   e.printStackTrace();
               }
               handler.sendEmptyMessage(0x123);
           }
       }
   }

   2. 使用AsyncTask異步任務

   • 注：更新UI的操作只能在onPostExecute(String result)方法中。

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     package com.example.runonuithreadtest;
     import android.app.Activity;
     import android.os.AsyncTask;
     import android.os.Bundle;
     import android.widget.TextView;
     public class MainActivity extends Activity {
         private TextView tv;
         @Override
         protected void onCreate(Bundle savedInstanceState) {
             super.onCreate(savedInstanceState);
             setContentView(R.layout.activity_main);
             tv = (TextView) findViewById(R.id.tv);
             new Yibu().execute();
         }
         class Yibu extends AsyncTask<String, String, String>
         {
             @Override
             protected String doInBackground(String... params) {
                 try {
                     Thread.sleep(2000);
                 } catch (InterruptedException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
                 return null;
             }
             @Override
             protected void onPostExecute(String result) {
                 // TODO Auto-generated method stub
                 tv.setText("更新后的TextView");
             }
         }
     }

     3. 使用runOnUiThread(action)方法

     package com.example.runonuithreadtest;
     import android.app.Activity;
     import android.os.Bundle;
     import android.widget.TextView;
     public class MainActivity extends Activity {
         private TextView tv;
         @Override
         protected void onCreate(Bundle savedInstanceState) {
             super.onCreate(savedInstanceState);
             setContentView(R.layout.activity_main);
             tv = (TextView) findViewById(R.id.tv);
             new MyThread().start();
         }
         class MyThread extends Thread
         {
             @Override
             public void run() {
                 runOnUiThread(new Runnable() {
                     @Override
                     public void run() {
                         // TODO Auto-generated method stub
                             try {
                                 //延遲兩秒更新
                                 Thread.sleep(2000);
                             } catch (InterruptedException e) {
                                 e.printStackTrace();
                             }
                             tv.setText("更新后的TextView");
                     }
                 });
             }
         }
     }

     4. 使用Handler的post(Runnabel r)方法

     package com.example.runonuithreadtest;
     import android.app.Activity;
     import android.os.Bundle;
     import android.os.Handler;
     import android.widget.TextView;
     public class MainActivity extends Activity {
         private TextView tv;
         @Override
         protected void onCreate(Bundle savedInstanceState) {
             super.onCreate(savedInstanceState);
             setContentView(R.layout.activity_main);
             tv = (TextView) findViewById(R.id.tv);
             Handler handler = new Handler();
             handler.post(new Runnable(){
                 @Override
                 public void run() {
                     try {
                         //延遲兩秒更新
                         Thread.sleep(2000);
                     } catch (InterruptedException e) {
                         e.printStackTrace();
                     }
                     tv.setText("更新后的TextView");
                 }
             });
         }
     }

     </div> 原文 http://segmentfault.com/a/1190000003702775