Android 异步上载图片 - Runnable 方式

Android 异步下载图片 -- Runnable 方式

习惯先上图：

主要代码：

public class MainActivity extends Activity {Dialog dialog;Bitmap bitmap;    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        Button btn=(Button) findViewById(R.id.main_do);        btn.setOnClickListener(new OnClickListener(){public void onClick(View arg0) {dialog = ProgressDialog.show(MainActivity.this, "wait",  "图片下载中 …", true, true);handler.post(new Runnable(){public void run() {try{//下载图片，随便搜索了个，开始度娘了一张图片，竟然下不下来，坑爹URL  url = new URL("http://tupian.qqjay.com/u/2012/0301/cdb1df16018702727988083e1f03b703.jpg");                        HttpURLConnection conn  = (HttpURLConnection)url.openConnection();                        conn.setDoInput(true);                        conn.connect();                         InputStream inputStream=conn.getInputStream();                        bitmap = BitmapFactory.decodeStream(inputStream);                        //下载完成，向handler发送消息                        Message m=new Message();                        m.what=1;                        handler.sendMessage(m);}catch(Exception e){e.printStackTrace();}}});}        });    }    private Handler handler=new Handler(){        public void handleMessage(Message msg){            switch(msg.what){            case 1:            //更新显示图片，销毁dialog                ImageView view=(ImageView)findViewById(R.id.main_pic);                view.setImageBitmap(bitmap);                dialog.dismiss();                break;            }        }    };    }