Activity与Service通信之BroadcastReceive

上一篇演示了使用Bound Service实现Activity与Service之间的通信，实现了在Activity中很容易调用Service中的方法，但如果需要在Activity中得到Service中某个变量的变化，就比较费劲了，如果遇到这样的需求，使用广播是很好的选择！

下面演示在Activity中如何得到Service中某个变量的变化以更新Activity的UI。

先看Service：

package com.gufengxiachen.broadcast;

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



public class LocalService extends Service{
	private int progress;
	@Override
	public IBinder onBind(Intent intent) {
		// TODO Auto-generated method stub
		return null;
	}
	
	@Override
	public void onStart(Intent intent, int startId) {
		// TODO Auto-generated method stub
		super.onStart(intent, startId);
		//得到Activity中传递过来的数据
		progress = intent.getIntExtra("progress", 0);
		//创建一个线程，每隔一秒向Activity发送一个广播，并将progress的新值发送出去
		new Thread(){
			public void run() {
				while(progress<100){
					progress = progress+1;
					Intent intent = new Intent();
					intent.putExtra("serviceProgress", progress);
					//设置发送广播的类型，可以随便写一个
					intent.setAction("com.gufengxiachen.service");
					sendBroadcast(intent);
					try {
						sleep(1000);
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
			}
		}.start();
	}
	

}

下面是Activity：

package com.gufengxiachen.broadcast;

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.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;

public class BroadcastReceiverTestActivity extends Activity {
    
	private ProgressBar progressBar;
	private Button button;
	private int progress = 0;
	private MyBroadcastReceiver myBroadcastReceiver = new MyBroadcastReceiver();
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        progressBar = (ProgressBar)findViewById(R.id.progressBar);
        button = (Button)findViewById(R.id.button);
        progressBar.setMax(100);
        button.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				//在这里启动服务
				Intent intent  = new Intent();
		    	intent.putExtra("progress", progress);
		    	intent.setClass(BroadcastReceiverTestActivity.this, LocalService.class);
		    	startService(intent);
			}
		});
       
    }
    
    @Override
    protected void onResume() {
    	// TODO Auto-generated method stub
    	super.onResume();
    	//注册广播接收器
    	IntentFilter filter = new IntentFilter();
    	//设置接收广播的类型，这里要和Service里设置的类型匹配，还可以在AndroidManifest.xml文件中注册
    	filter.addAction("com.gufengxiachen.service");
    	this.registerReceiver(myBroadcastReceiver, filter);

    }
    
    @Override
    protected void onStop() {
    	// TODO Auto-generated method stub
    	super.onStop();
    	this.unregisterReceiver(myBroadcastReceiver);
    }
    //定义一个广播接收器
    class MyBroadcastReceiver extends BroadcastReceiver{
    	@Override
    	public void onReceive(Context context, Intent intent) {
    		// TODO Auto-generated method stub
    		//接收到Service发送的广播信息，得到数据，更新UI
    		progress = intent.getIntExtra("serviceProgress", 0);
    		progressBar.setProgress(progress);
    	}
    }
}

运行的效果就是，每隔一秒Service发送一个广播，同时广播接收器接收广播，得到数据，更新UI。