Android(安卓)Service和广播联合更新UI的例子

在Android中，异步更新UI，通常我们会选用Handler启动线程，或者sendMessage的方式，那么利用Service和广播也可以更新UI的，例子如下：我们建立一个Service：

package com.andyimport android.app.Service;//引入相关包import android.content.BroadcastReceiver;//引入相关包import android.content.Context;//引入相关包import android.content.Intent;//引入相关包import android.content.IntentFilter;//引入相关包import android.os.IBinder;//引入相关包//继承自Service的子类public class MyService extends Service{       CommandReceiver cmdReceiver;       boolean flag;       @Override       public void onCreate(){//重写onCreate方法              flag = true;              cmdReceiver = newCommandReceiver();             super.onCreate();       }       @Override       public IBinder onBind(Intent intent){//重写onBind方法              // TODO Auto-generated methodstub              return null;       }       @Override       public int onStartCommand(Intent intent, intflags, int startId) {//重写onStartCommand方法              IntentFilter filter = newIntentFilter();//创建IntentFilter对象             filter.addAction("wyf.wpf.MyService");              registerReceiver(cmdReceiver,filter);//注册Broadcast Receiver             doJob();//调用方法启动线程              returnsuper.onStartCommand(intent, flags, startId);       }       //方法：       public void doJob(){              newThread(){                     publicvoid run(){                           while(flag){                                  try{//睡眠一段时间                                        Thread.sleep(1000);                                  }                                  catch(Exceptione){                                        e.printStackTrace();                                  }                                  Intent intent = newIntent();//创建Intent对象                                 intent.setAction("wyf.wpf.Sample_3_6");                                  intent.putExtra("data",Math.random());                                 sendBroadcast(intent);//发送广播                           }                                              }                                  }.start();       }             private class CommandReceiver extendsBroadcastReceiver{//继承自BroadcastReceiver的子类              @Override              public void onReceive(Contextcontext, Intent intent) {//重写onReceive方法                     int cmd =intent.getIntExtra("cmd", -1);//获取Extra信息                     if(cmd ==Sample_3_6.CMD_STOP_SERVICE){//如果发来的消息是停止服务                                                     flag = false;//停止线程                           stopSelf();//停止服务                    }              }                    }       @Override       public void onDestroy(){//重写onDestroy方法             this.unregisterReceiver(cmdReceiver);//取消注册的CommandReceiver             super.onDestroy();       }      }

建立一个activity

package com.andy;//声明包语句import android.app.Activity;//引入相关包import android.content.BroadcastReceiver;//引入相关包import android.content.Context;//引入相关包import android.content.Intent;//引入相关包import android.content.IntentFilter;//引入相关包import android.os.Bundle;//引入相关包import android.view.View;//引入相关包import android.view.View.OnClickListener;//引入相关包import android.widget.Button;//引入相关包import android.widget.TextView;//引入相关包//继承自Activity的子类public class Sample_3_6 extends Activity {       public static final int CMD_STOP_SERVICE =0;       ButtonbtnStart;//开始服务Button对象应用       Button btnStop;//停止服务Button对象应用       TextView tv;//TextView对象应用       DataReceiverdataReceiver;//BroadcastReceiver对象       @Override    public void onCreate(BundlesavedInstanceState) {//重写onCreate方法       super.onCreate(savedInstanceState);       setContentView(R.layout.main);//设置显示的屏幕       btnStart =(Button)findViewById(R.id.btnStart);       btnStop =(Button)findViewById(R.id.btnStop);       tv =(TextView)findViewById(R.id.tv);       btnStart.setOnClickListener(newOnClickListener() {//为按钮添加点击事件监听                                 @Override                     publicvoid onClick(View v) {//重写onClick方法                           Intent myIntent = new Intent(Sample_3_6.this,wyf.wpf.MyService.class);                          Sample_3_6.this.startService(myIntent);//发送Intent启动Service                    }              });       btnStop.setOnClickListener(newOnClickListener() {//为按钮添加点击事件监听                          @Override                     publicvoid onClick(View v) {//重写onClick方法                           Intent myIntent = newIntent();//创建Intent对象                          myIntent.setAction("wyf.wpf.MyService");                           myIntent.putExtra("cmd",CMD_STOP_SERVICE);                           sendBroadcast(myIntent);//发送广播                    }              });    }             private class DataReceiver extendsBroadcastReceiver{//继承自BroadcastReceiver的子类              @Override              public void onReceive(Contextcontext, Intent intent) {//重写onReceive方法                     doubledata = intent.getDoubleExtra("data", 0);                    tv.setText("Service的数据为:"+data);                                 }                    }       @Override       protected void onStart(){//重写onStart方法              dataReceiver = newDataReceiver();              IntentFilter filter = newIntentFilter();//创建IntentFilter对象             filter.addAction("wyf.wpf.Sample_3_6");             registerReceiver(dataReceiver, filter);//注册BroadcastReceiver             super.onStart();       }       @Override       protected void onStop(){//重写onStop方法             unregisterReceiver(dataReceiver);//取消注册BroadcastReceiver             super.onStop();       }}

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