Android 异步下载,Android异步下载

[android]代码库//前台ui线程在显示ProgressDialog，

//后台线程在下载数据，数据下载完毕，关闭进度框

@Override

public void onClick (View view) {

switch (view.getId() ) {

case R.id.btnFirst:

dialog = ProgressDialog.show (this, "",

"下载数据，请稍等 …", true, true);

//启动一个后台线程

handler.post (new Runnable() {

@Override

public void run() {

//这里下载数据

try {

URL url = new URL (params);

HttpURLConnection conn = (HttpURLConnection) url.openConnection();

conn.setDoInput (true);

conn.connect();

InputStream inputStream = conn.getInputStream();

bitmap = BitmapFactory.decodeStream (inputStream);

Message msg = new Message();

msg.what = 1;

handler.sendMessage (msg);

} catch (MalformedURLException e1) {

e1.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

});

break;