Service通过广播Broadcast更新Activity UI

今天学习到Service,在用Service下载文件时,一个问题就是Service没有界面,如何通知用户当前下载的进度,Service直接向Activity传数据有点麻烦,于是想到了用Broadcast,Service广播,Activity负责接收,再对接收到的数据进行处理,就达到了我们的目的。下面是今天这个程序的运行效果:

先注册Receiver,然后开始Service,上面的TextView和ProgressBar就会随着Service传过来的值变,解除注册Receiver或者结束Service后不会再变。
Service代码:


package com.services;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;

public class TestService extends Service {
	boolean isStop=false;
	@Override
	public IBinder onBind(Intent intent) {
		// TODO Auto-generated method stub
		Log.i("TAG","绑定");
		return null;
	}
	public void onCreate(){
		Log.i("TAG","Services onCreate");
		super.onCreate();
	}
	public void onStart(Intent intent,int startId){
		Log.i("TAG","Services onStart");
		super.onStart(intent, startId);
		new Thread(){//新建线程,每隔1秒发送一次广播,同时把i放进intent传出
			public void run(){
				int i=0;
				while(!isStop){
					Intent intent=new Intent();
					intent.putExtra("i", i);
					i++;
					intent.setAction("android.intent.action.test");//action与接收器相同
					sendBroadcast(intent);
					Log.i("TAG",String.valueOf(i));
					try {
						sleep(1000);
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			}
		}.start();

	}
	@Override
	public void onDestroy() {
		Log.i("TAG","Services onDestory");
		isStop=true;//即使service销毁线程也不会停止,所以这里通过设置isStop来停止线程
		super.onDestroy();
	}

}

Activity代码:


package com.services;


import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

public class main extends Activity {
	/** Called when the activity is first created. */
	Button b1,b2,b3,b4;
	TestService mService;
	ProgressBar pb;
	MyReceiver receiver;
	TextView tv;
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		b1=(Button)findViewById(R.id.b1);
		b2=(Button)findViewById(R.id.b2);
		b3=(Button)findViewById(R.id.b3);
		b4=(Button)findViewById(R.id.b4);
		b1.setOnClickListener(l1);
		b2.setOnClickListener(l2);
		b3.setOnClickListener(l3);
		b4.setOnClickListener(l4);
		pb=(ProgressBar)findViewById(R.id.pb);
		tv=(TextView)findViewById(R.id.tv);
	}
	
	
	
	public class MyReceiver extends BroadcastReceiver {
		//自定义一个广播接收器
		@Override
		public void onReceive(Context context, Intent intent) {
			// TODO Auto-generated method stub
			System.out.println("OnReceiver");
			Bundle bundle=intent.getExtras();
			int a=bundle.getInt("i");
			pb.setProgress(a);
			tv.setText(String.valueOf(a));
			//处理接收到的内容
	
		}
		public MyReceiver(){
			System.out.println("MyReceiver");
			//构造函数,做一些初始化工作,本例中无任何作用
		}

	}
	

	OnClickListener l1=new OnClickListener(){

		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			startService(new Intent(main.this, TestService.class));
			//开始服务
		}

	};
	OnClickListener l2=new OnClickListener(){

		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			stopService(new Intent(main.this, TestService.class));
			//结束服务
		}

	};
	OnClickListener l3=new OnClickListener(){

		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			//注册接收器
			receiver=new MyReceiver();
			IntentFilter filter=new IntentFilter();
			filter.addAction("android.intent.action.test");
			main.this.registerReceiver(receiver,filter);
		}

	};
	OnClickListener l4=new OnClickListener(){

		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub			
			main.this.unregisterReceiver(receiver);
			//解除注册接收器
		}

	};
}

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