android URL讀取網絡資源



Thread類中run()和start()方法的區別如下：
run()方法:在本線程內調用該Runnable對象的run()方法，可以重複多次調用；
start()方法:啓動一個線程，調用該Runnable對象的run()方法，不能多次啓動一個線程；

public class MainActivity extends Activity {

 private ImageView iv ;
 private Bitmap mbitmap;
 Handler mhandle = new Handler(){
  @Override
  public void handleMessage(Message msg) {
   if(msg.what==0x123){
    iv.setImageBitmap(mbitmap);
   }
  }
 };
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  iv = (ImageView) findViewById(R.id.imageView1);
  new Thread(){
   @Override
   public void run() {
    try {
     URL url = new URL("http://a2.att.hudong.com/04/58/300001054794129041580438110.jpg");
     InputStream is = url.openStream();
     mbitmap = BitmapFactory.decodeStream(is);
     mhandle.sendEmptyMessage(0x123);
     is.close();
     //再次打開，下載到本地
     is = url.openStream();
     OutputStream os = openFileOutput("cray.png", MODE_WORLD_READABLE);
     byte [] buff = new byte[1024];
     int hasread =0;
     while((hasread=is.read(buff))>0){
      os.write(buff, 0, hasread);
     }
     os.close();
     is.close();
    } catch (MalformedURLException e) {
     e.printStackTrace();
    } catch (IOException e) {
     e.printStackTrace();
    }
   }
  }.start();
  
  
 
 }

}