Android 利用Service实现下载网络图片至sdk卡

 package com.example.myapp5;

 import android.app.Activity;
 import android.content.Intent;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.Button;
 /**
  * Android 利用service实现下载图片功能
  * @author shaobn
  * @date 2015-9-14
  * @packege com.example.myapp5.MyApp5
  */
 public class MainActivity extends Activity {
     private Button button;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         button = (Button) this.findViewById(R.id.button1);
         button.setOnClickListener(new View.OnClickListener() {

             @Override
             public void onClick(View arg0) {
                 // TODO Auto-generated method stub
                 Intent intent = new Intent(MainActivity.this,MyService.class);
                 startService(intent);
             }
         });
     }
 }

 package com.example.myapp5;

 import java.io.File;
 import java.io.FileOutputStream;

 import org.apache.http.HttpResponse;
 import org.apache.http.client.HttpClient;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.impl.client.DefaultHttpClient;
 import org.apache.http.util.EntityUtils;

 import android.app.Service;
 import android.content.Intent;
 import android.os.Environment;
 import android.os.Handler;
 import android.os.IBinder;
 import android.os.Message;
 import android.widget.Toast;

 public class MyService extends Service {
     private final static String IMAGEPAH = "https://www.baidu.com/img/bd_logo1.png";
     @Override
     public void onCreate() {
         // TODO Auto-generated method stub
         super.onCreate();
     }
     @Override
     public IBinder onBind(Intent arg0) {
         // TODO Auto-generated method stub
         return null;
     }

     @Override
     public int onStartCommand(Intent intent, int flags, int startId) {
         // TODO Auto-generated method stub
         final Handler handler = new Handler(){

             public void handleMessage(android.os.Message msg) {
                 if(msg.what==1){
                     Toast.makeText(getApplicationContext(), "关闭了", 1).show();
                     stopSelf();
                 }
             };

         };
         new Thread(new Runnable() {

             @Override
             public void run() {
                 // TODO Auto-generated method stub
                 HttpClient httpClient = new DefaultHttpClient();
                 HttpGet httpGet = new HttpGet(IMAGEPAH);
                 HttpResponse httpResponse = null;
                 File file = Environment.getExternalStorageDirectory();
                 File file2 = null;
                 FileOutputStream fos = null;
                 try {
                 httpResponse =httpClient.execute(httpGet);
                 if (httpResponse.getStatusLine().getStatusCode()==200) {
                     byte[] num = EntityUtils.toByteArray(httpResponse.getEntity());
                     if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
                         file2 = new File(file, "/Movies/a.jpg");
                         file2.createNewFile();
                         fos = new FileOutputStream(file2);
                         fos.write(num);
                         Message message = Message.obtain();
                         message.what = 1;
                         handler.sendMessage(message);
                     }
                 }

                 } catch (Exception e) {
                     e.printStackTrace();// TODO: handle exception
                 }finally{
                     if(fos!=null){
                         try {
                             fos.close();
                         } catch (Exception e2) {
                             // TODO: handle exception
                             e2.printStackTrace();
                         }
                     }

                 }

             }
         }).start();
         return super.onStartCommand(intent, flags, startId);
     }
     @Override
     public void onDestroy() {
         // TODO Auto-generated method stub
         super.onDestroy();
     }
 }