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);
         }
     }

 }

MainActivity.java

 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---");
     }

 }

DownLoadService.java

 <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>

activity_main.xml

至于服务的类都需要注册  这里就不写了