public class ImageTest extends Activity{

private ImageView mImageView;

private ProgressBar mProgressBar;

private static String URL="http://img.my.csdn.net/uploads/201504/12/1428806103_9476.png";

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

setContentView(R.layout.image);

mImageView=(ImageView) findViewById(R.id.image);

mProgressBar=(ProgressBar) findViewById(R.id.progressbar);

new MyAsyncTask().execute(URL);

}

class MyAsyncTask extends AsyncTask<String, Void, Bitmap>{

@Override

protected void onPreExecute() {

super.onPreExecute();

mProgressBar.setVisibility(View.VISIBLE);

}

@Override

protected void onPostExecute(Bitmap bitmap) {

// TODO Auto-generated method stub

super.onPostExecute(bitmap);

mProgressBar.setVisibility(View.GONE);

mImageView.setImageBitmap(bitmap);

}

@Override

protected Bitmap doInBackground(String... params) {

String url=params[0];

Bitmap bitmap=null;

URLConnection connection;

InputStream is;

try {

connection=new URL(url).openConnection();

is=connection.getInputStream();

BufferedInputStream bis=new BufferedInputStream(is);

Thread.sleep(3000);

bitmap=BitmapFactory.decodeStream(bis);

is.close();

bis.close();

} catch (IOException e) {

e.printStackTrace();

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return bitmap;

}

}

}

public class MainActivity extends Activity {

? ? @Override

? ? protected void onCreate(Bundle savedInstanceState) {

? ? ? ? super.onCreate(savedInstanceState);

? ? ? ? setContentView(R.layout.activity_main);

? ? ? ? MyAsyncTask task=new MyAsyncTask();

? ? ? ? task.execute();

? ? }

? ??

? ? @SuppressWarnings("unused")

private void loadImage(View view){

? ? startActivity(new Intent(this,ImageTest.class));

? ? }

}

public class MyAsyncTask extends AsyncTask<Void, Void, Void>{

@Override

protected Void doInBackground(Void... params) {

// TODO Auto-generated method stub

Log.d("xys", "doInBackground");

publishProgress();

return null;

}

@Override

protected void onPreExecute() {

// TODO Auto-generated method stub

super.onPreExecute();

Log.d("xys", "onPreExecute");

}

@Override

protected void onPostExecute(Void result) {

// TODO Auto-generated method stub

super.onPostExecute(result);

Log.d("xys", "onPostExecute");

}

@Override

protected void onProgressUpdate(Void... values) {

// TODO Auto-generated method stub

super.onProgressUpdate(values);

Log.d("xys", "onProgressUpdate");

}

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

? ? android:layout_width="match_parent"

? ? android:layout_height="match_parent"

? ? android:padding="16dp">

? ??

? ??

? ??

? ? <ImageView?

? ? ? ? android:id="@+id/image"

? ? ? ? android:layout_width="match_parent"

? ? ? ? android:layout_height="match_parent"

? ? ? ? />

? ? <ProgressBar

? ? ? ? android:id="@+id/progressbar"

? ? ? ? android:visibility="gone"

? ? ? ? android:layout_centerInParent="true"

? ? ? ? ?android:layout_width="wrap_content"

? ? ? ? android:layout_height="wrap_content"

? ? ? ? />

</RelativeLayout>

<LinearLayout 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="com.example.dan55.MainActivity" >

? ? <Button

? ? ? ? android:onClick="loadImage"

? ? ? ? android:layout_width="match_parent"

? ? ? ? android:layout_height="wrap_content"

? ? ? ? android:text="Image Test" />

</LinearLayout>