你的位置:首页 > 操作系统

[操作系统]android handler runnable使用实例(关键是内部run中停止)


.java

 1 package com.example.mydemo; 2  3 import android.app.Activity; 4 import android.os.Bundle; 5 import android.os.Handler; 6 import android.os.Message; 7 import android.view.View; 8 import android.view.View.OnClickListener; 9 import android.widget.Button;10 import android.widget.TextView;11 12 public class MainActivity extends Activity {13   private TextView text_view = null;14   private Button start = null;15   private Button end = null;16   private int count = 0;17   // 使用handler时首先要创建一个handler18   Handler handler = new Handler();19   // 要用handler来处理多线程可以使用runnable接口,这里先定义该接口20   // 线程中运行该接口的run函数21   Runnable update_thread = new Runnable() {22     public void run() {23       // 线程每次执行时输出"UpdateThread..."文字,且自动换行24       // textview的append功能和Qt中的append类似,不会覆盖前面25       // 的内容,只是Qt中的append默认是自动换行模式26       // text_view.append("\nUpdateThread...");27       text_view.setText(String.valueOf(count++));28       // 延时1s后又将线程加入到线程队列中29       if (count >= 5) {30         // handler.removeCallbacks(update_thread);//用此行停止不行,需要发消息外部停止才可以。不明白?31         Message message = new Message();32         message.what = 1;33         handlerStop.sendMessage(message);34       }35       handler.postDelayed(update_thread, 1000);36 37     }38   };39 40   @Override41   public void onCreate(Bundle savedInstanceState) {42     super.onCreate(savedInstanceState);43     setContentView(R.layout.activity_main);44 45     text_view = (TextView) findViewById(R.id.text_view);46     start = (Button) findViewById(R.id.start);47     start.setOnClickListener(new StartClickListener());48     end = (Button) findViewById(R.id.end);49     end.setOnClickListener(new EndClickListener());50     handler.post(update_thread);51   }52 53   private class StartClickListener implements OnClickListener {54     public void onClick(View v) {55       // TODO Auto-generated method stub56       // 将线程接口立刻送到线程队列中57       handler.post(update_thread);58     }59   }60 61   private class EndClickListener implements OnClickListener {62     public void onClick(View v) {63       // TODO Auto-generated method stub64       // 将接口从线程队列中移除65       count = 0;66       handler.removeCallbacks(update_thread);67     }68   }69 70   final Handler handlerStop = new Handler() {71     public void handleMessage(Message msg) {72       switch (msg.what) {73       case 1:74         count = 0;75         handler.removeCallbacks(update_thread);76         break;77       }78       super.handleMessage(msg);79     }80 81   };82 }

.

 1 <LinearLayout  2    3   android:layout_width="match_parent" 4   android:layout_height="match_parent" 5   android:orientation="vertical" > 6  7   <TextView 8     android:id="@+id/text_view" 9     android:layout_width="fill_parent"10     android:layout_height="200dip"11     android:text="@string/hello_world"12     tools:context=".MainActivity" />13 14   <Button15     android:id="@+id/start"16     android:layout_width="fill_parent"17     android:layout_height="wrap_content"18     android:text="start" />19 20   <Button21     android:id="@+id/end"22     android:layout_width="fill_parent"23     android:layout_height="wrap_content"24     android:text="end" />25 26 </LinearLayout>