public class ExampleActivity extends Activity {
public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private Button startBtn;
private ProgressDialog mProgressDialog;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
startBtn = (Button)findViewById(R.id.startBtn);
startBtn.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
startDownload();
}
});
}
private void startDownload() {
String url = "http://farm1.static.flickr.com/114/298125983_0e4bf66782_b.jpg";
new DownloadFileAsync().execute(url);
}
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case DIALOG_DOWNLOAD_PROGRESS:
mProgressDialog = new ProgressDialog(this);
mProgressDialog.setMessage("Downloading file..");
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mProgressDialog.setCancelable(true);
mProgressDialog.setButton("Cancel", new CancelOnClickListener());
mProgressDialog.show();
return mProgressDialog;
default:
return null;
}
}
private final class CancelOnClickListener implements DialogInterface.OnClickListener {
public void onClick(DialogInterface dialog, int which) {
ExampleActivity.this.finish();
dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
new DownloadFileAsync().cancel(true);
}
}
class DownloadFileAsync extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(DIALOG_DOWNLOAD_PROGRESS);
}
@Override
protected String doInBackground(String... aurl) {
int count;
try
{
URL url = new URL(aurl[0]);
URLConnection conexion = url.openConnection();
conexion.connect();
int lenghtOfFile = conexion.getContentLength();
Log.d("ANDRO_ASYNC", "Lenght of file: " + lenghtOfFile);
InputStream input = new BufferedInputStream(url.openStream());
OutputStream output = new FileOutputStream("/sdcard/some_photo_from_gdansk_poland.jpg");
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
publishProgress(""+(int)((total*100)/lenghtOfFile));
output.write(data, 0, count);
}
output.flush();
output.close();
input.close();
}
catch (Exception e) {
}
return null;
}
protected void onProgressUpdate(String... progress) {
Log.d("ANDRO_ASYNC",progress[0]);
mProgressDialog.setProgress(Integer.parseInt(progress[0]));
}
@Override
protected void onPostExecute(String unused) {
dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
}
}
}
在这里如果我点击开始按钮,它将自动下载文件。但我想取消下载(如果我不喜欢),所以我把 mProgressDialog.setButton("Cancel", new CancelOnClickListener());
它退出应用程序。但文件正在下载。如何更改功能在 doInBackground() 里面