308
Android Service和廣播聯合更新UI的例子
在Android中，異步更新UI，通常我們會選用Handler啟動線程，或者sendMessage的方式，那麼利用Service和廣播也可以更新UI的，例子如下：我們建立一個Service：
package com.andy
import android.app.Service;//引入相關包
import android.content.BroadcastReceiver;//引入相關包
import android.content.Context;//引入相關包
import android.content.Intent;//引入相關包
import android.content.IntentFilter;//引入相關包
import android.os.IBinder;//引入相關包
//繼承自Service的子類
public class MyService extends Service{
CommandReceiver cmdReceiver;
boolean flag;
@Override
public void onCreate(){//重寫onCreate方法
flag = true;
cmdReceiver = newCommandReceiver();
super.onCreate();
}
@Override
public IBinder onBind(Intent intent){//重寫onBind方法
// TODO Auto-generated methodstub
return null;
}
@Override
public int onStartCommand(Intent intent, intflags, int startId) {//重寫onStartCommand方法
IntentFilter filter = newIntentFilter();//創建IntentFilter對象
filter.addAction("wyf.wpf.MyService");
registerReceiver(cmdReceiver,filter);//注冊Broadcast Receiver
doJob();//調用方法啟動線程
returnsuper.onStartCommand(intent, flags, startId);
}
//方法：
public void doJob(){
newThread(){
publicvoid run(){
while(flag){
try{//睡眠一段時間
Thread.sleep(1000);
}
catch(Exceptione){
e.printStackTrace();
}
Intent intent = newIntent();//創建Intent對象
intent.setAction("wyf.wpf.Sample_3_6");
intent.putExtra("data",Math.random());
sendBroadcast(intent);//發送廣播
}
}
}.start();
}
private class CommandReceiver extendsBroadcastReceiver{//繼承自BroadcastReceiver的子類
@Override
public void onReceive(Contextcontext, Intent intent) {//重寫onReceive方法
int cmd =intent.getIntExtra("cmd", -1);//獲取Extra信息
if(cmd ==Sample_3_6.CMD_STOP_SERVICE){//如果發來的消息是停止服務
flag = false;//停止線程
stopSelf();//停止服務
}
}
}
@Override
public void onDestroy(){//重寫onDestroy方法
this.unregisterReceiver(cmdReceiver);//取消注冊的CommandReceiver
super.onDestroy();
}
}
建立一個activitypackage com.andy;//聲明包語句
import android.app.Activity;//引入相關包
import android.content.BroadcastReceiver;//引入相關包
import android.content.Context;//引入相關包
import android.content.Intent;//引入相關包
import android.content.IntentFilter;//引入相關包
import android.os.Bundle;//引入相關包
import android.view.View;//引入相關包
import android.view.View.OnClickListener;//引入相關包
import android.widget.Button;//引入相關包
import android.widget.TextView;//引入相關包
//繼承自Activity的子類
public class Sample_3_6 extends Activity {
public static final int CMD_STOP_SERVICE =0;
ButtonbtnStart;//開始服務Button對象應用
Button btnStop;//停止服務Button對象應用
TextView tv;//TextView對象應用
DataReceiverdataReceiver;//BroadcastReceiver對象
@Override
public void onCreate(BundlesavedInstanceState) {//重寫onCreate方法
super.onCreate(savedInstanceState);
setContentView(R.layout.main);//設置顯示的屏幕
btnStart =(Button)findViewById(R.id.btnStart);
btnStop =(Button)findViewById(R.id.btnStop);
tv =(TextView)findViewById(R.id.tv);
btnStart.setOnClickListener(newOnClickListener() {//為按鈕添加點擊事件監聽
@Override
publicvoid onClick(View v) {//重寫onClick方法
Intent myIntent = new Intent(Sample_3_6.this,wyf.wpf.MyService.class);
Sample_3_6.this.startService(myIntent);//發送Intent啟動Service
}
});
btnStop.setOnClickListener(newOnClickListener() {//為按鈕添加點擊事件監聽
@Override
publicvoid onClick(View v) {//重寫onClick方法
Intent myIntent = newIntent();//創建Intent對象
myIntent.setAction("wyf.wpf.MyService");
myIntent.putExtra("cmd",CMD_STOP_SERVICE);
sendBroadcast(myIntent);//發送廣播
}
});
}
private class DataReceiver extendsBroadcastReceiver{//繼承自BroadcastReceiver的子類
@Override
public void onReceive(Contextcontext, Intent intent) {//重寫onReceive方法
doubledata = intent.getDoubleExtra("data", 0);
tv.setText("Service的數據為:"+data);
}
}
@Override
protected void onStart(){//重寫onStart方法
dataReceiver = newDataReceiver();
IntentFilter filter = newIntentFilter();//創建IntentFilter對象
filter.addAction("wyf.wpf.Sample_3_6");
registerReceiver(dataReceiver, filter);//注冊BroadcastReceiver
super.onStart();
}
@Override
protected void onStop(){//重寫onStop方法
unregisterReceiver(dataReceiver);//取消注冊BroadcastReceiver
super.onStop();
}
}
最後更新：2017-04-03 21:30:11