IntentService----意图服务

意图服务是异步进行的  执行完操作后就会自己消毁（onDestroy方法）

本例为点击按钮下载三张图片相当于连续执行三次意图服务中的onStartcommand方法

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.RelativeLayout;

public class MainActivity extends Activity {

    private ImageView img1View,img2View,img3View;
    private RelativeLayout mainLayout;
    
    private ImgReceiver imgReceiver;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        mainLayout=(RelativeLayout) findViewById(R.id.mainLayoutId);
        
        img1View=(ImageView) findViewById(R.id.img1Id);
        img2View=(ImageView) findViewById(R.id.img2Id);
        img3View=(ImageView) findViewById(R.id.img3Id);
        
        img1View.setTag(Config.URL1);
        img2View.setTag(Config.URL2);
        img3View.setTag(Config.URL3);
        
        imgReceiver=new ImgReceiver();
        registerReceiver(imgReceiver, 
                new IntentFilter(Config.ACTION_DOWNLOAD_COMPLETED));
                
    }
    
    public void startDownload(View view){
        Intent intent=new Intent(getApplicationContext(),DownloadService.class);
        intent.putExtra("path", Config.URL1);
        startService(intent); //涓嬭浇绗�竴涓�浘鐗�        
        intent.putExtra("path", Config.URL2);
        startService(intent); //涓嬭浇绗�簩涓�浘鐗�        
        intent.putExtra("path", Config.URL3);
        startService(intent); //涓嬭浇绗�笁涓�浘鐗�        
    }
    
    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(imgReceiver); //鍙栨秷娉ㄥ唽骞挎挱鎺ユ敹鍣�    
        }
    
    class ImgReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(Context context, Intent intent) {
            // TODO 鎺ユ敹鍥剧墖涓嬭浇瀹屾垚鐨勫箍鎾�            
            String url=intent.getStringExtra(Config.EXTRA_URL);
            Bitmap bitmap=intent.getParcelableExtra(Config.EXTRA_BITMAP);
            
            //鏍规嵁Url浣滀负鐨勫浘鐗囨帶浠剁殑鏍囩�鏌ユ壘鍥剧墖鎺т欢
            ImageView imgView=(ImageView) mainLayout.findViewWithTag(url);
            imgView.setImageBitmap(bitmap);
        }
    }

}

import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import android.app.IntentService;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;

/**
 * IntentService鏄�甫鏈夊瓙绾跨▼鐨勬湇鍔＄粍浠讹紝鍏跺唴閮ㄤ娇鐢ㄤ簡鍗曠嚎绋嬫睜妯″紡锛� * 褰撴墍鏈夌殑浠诲姟鎵ц�瀹屾垚鍚庯紝浼氳嚜鍔ㄥ叧闂�湰鏈嶅姟
 * 鍏剁敓鍛藉懆鏈熸柟娉曪細
 *     onCreate()
 *     onStartCommand()
 *     onHandleIntent() 鍦ㄥ瓙绾跨▼涓�墽琛岀殑鏂规硶
 *  onDestroy()
 *     
 * @author apple
 *
 */
public class DownloadService extends IntentService {
    public DownloadService(){
        super(null);//鍙傛暟锛氭槸璁剧疆瀛愮嚎绋嬬殑鍚嶇О
    }
    
    @Override
    public void onCreate() {
        super.onCreate();
        Log.i("debug", "--onCreate---");
    }
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i("debug", "--onStartCommand---");
        return super.onStartCommand(intent, flags, startId);
    }
    
    @Override
    protected void onHandleIntent(Intent intent) {
        // TODO 鍦ㄥ瓙绾跨▼涓�墽琛岀殑鏂规硶
        Log.i("debug", "--onHandleIntent---");
        //鑾峰彇涓嬭浇鍥剧墖鐨勫湴鍧�        
        String path=intent.getStringExtra("path");
        try{
            URL url=new URL(path);
            HttpURLConnection conn=(HttpURLConnection) url.openConnection();
            InputStream is=conn.getInputStream();
            byte[] buffer=new byte[10*1024];//姣忔�璇诲彇瀛楄妭鐨勬渶澶ф暟
            int len=-1;
            
            ByteArrayOutputStream baos=new ByteArrayOutputStream();
            if(conn.getResponseCode()==200){
                while((len=is.read(buffer))!=-1){
                    baos.write(buffer, 0, len);
                }
                
                byte[] bytes=baos.toByteArray();
                //灏嗕笅杞藉畬鎴愮殑瀛楄妭鏁扮粍杞�垚鍥剧墖瀵硅薄
                Bitmap bitmap=BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
                
                //灏嗗浘鐗囧�璞″彂閫佺粰Activity杩涜�鏄剧ず
                Intent bitmapIntent=new Intent(Config.ACTION_DOWNLOAD_COMPLETED);
                bitmapIntent.putExtra(Config.EXTRA_BITMAP,bitmap);
                bitmapIntent.putExtra(Config.EXTRA_URL, path);
                
                sendBroadcast(bitmapIntent);
                
                Thread.sleep(2000);//浠呮祴璇曟椂浣跨敤
            }
            
        }catch(Exception e){
            e.printStackTrace();
        }
        
    }
    
    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.i("debug", "--onDestroy---");
    }

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" 
    android:id="@+id/mainLayoutId">

    <Button
        android:id="@+id/btnId"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="startDownload"
        android:text="开始下载" />
    
    <ImageView
        android:id="@+id/img1Id"
        android:layout_width="100dp"
        android:layout_height="90dp"
        android:scaleType="centerCrop"
        android:layout_margin="5dp" 
        android:layout_below="@id/btnId"/>
    
    <ImageView
        android:id="@+id/img2Id"
        android:layout_width="100dp"
        android:layout_height="90dp"
        android:scaleType="centerCrop"
        android:layout_margin="5dp" 
        android:layout_below="@id/btnId"
        android:layout_toRightOf="@id/img1Id"/>
    
      <ImageView
        android:id="@+id/img3Id"
        android:layout_width="100dp"
        android:layout_height="90dp"
        android:scaleType="centerCrop"
        android:layout_margin="5dp" 
        android:layout_below="@id/img1Id"/>

</RelativeLayout>

至于服务的类都需要注册  这里就不写了