In my app, i have an asynchronous task that will download a file from a remote server.
In that class, I have set a ProgressDialog that has a cancel button. It could have been easier if I just use that async task once and by creating and instance of the AsyncTask.
I could have just call asyncTask.cancel(true), as what I saw on some samples.
But in my Activity, i have executed that AsyncTask many times like this:
new MyAsynTask().execute(url_of_file_1);
new MyAsynTask().execute(url_of_file_2);
new MyAsynTask().execute(url_of_file_3);
Though this isn't exactly the structure but the sense is something like this.
This is how the MyAsyncTask looks like:
private class MyAsyncTask extends AsyncTask<String, Integer, String> {
ProgressDialog pdialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
if(!MyActivity.this.isFinishing()){
mProgressDialog = new ProgressDialog(MyActivity.this);
mProgressDialog.setCancelable(false);
mProgressDialog.setButton(DialogInterface.BUTTON_POSITIVE, "Cancel", new CancelOnClickListener());
}
}
@Override
protected String doInBackground(String... fileUrl) {
try {
//do connection to url things
if(!isCancelled()){
// download the file
}else{
pdialog.dismiss();
mProgressDialog.dismiss();
}
}catch(MalformedURLException e){
}catch(FileNotFoundException e){
}catch(Exception e){
}
return null;
}
@Override
protected void onProgressUpdate(Integer... values) {
if(!MyActivity.this.isFinishing()){
mProgressDialog.setMessage("Downloading..." + values[0]);
mProgressDialog.show();
super.onProgressUpdate(values);
}
}
@Override
protected void onPostExecute(String result) {
if(!MyActivity.this.isFinishing()){
super.onPostExecute(result);
mProgressDialog.dismiss();
}
}
private final class CancelOnClickListener implements DialogInterface.OnClickListener {
public void onClick(DialogInterface dialog, int which) {
new MyAsyncTask().cancel(true); // is this correct?
MyActivity.this.finish();
try {
MyActivity.this.finalize();
} catch (Throwable e) {
application.shortToast("Error encountered in closing the page");
}
// maybe i should call super.onBackPressed();
application.shortToast("Download Cancelled");
}
}
}
What happened when i press cancel is that it always have this exception, but my app won't crash sometimes though...
08-14 23:07:12.702: E/WindowManager(8623): Activity com.android.app.MyActivityhas leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@43f7c938 that was originally added here
08-14 23:07:12.702: E/WindowManager(8623): android.view.WindowLeaked: Activity com.android.app.MyActivityhas leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@43f7c938 that was originally added here
08-14 23:07:12.702: E/WindowManager(8623): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:384)
08-14 23:07:12.702: E/WindowManager(8623): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:292)
08-14 23:07:12.702: E/WindowManager(8623): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:224)
08-14 23:07:12.702: E/WindowManager(8623): at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:149)
08-14 23:07:12.702: E/WindowManager(8623): at android.view.Window$LocalWindowManager.addView(Window.java:547)
08-14 23:07:12.702: E/WindowManager(8623): at android.app.Dialog.show(Dialog.java:285)
08-14 23:07:12.702: E/WindowManager(8623): at com.android.app.MyActivity$MyAsyncTask.onPreExecute(PartsActivity.java:784)
08-14 23:07:12.702: E/WindowManager(8623): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
08-14 23:07:12.702: E/WindowManager(8623): at android.os.AsyncTask.execute(AsyncTask.java:534)
08-14 23:07:12.702: E/WindowManager(8623): at com.android.app.MyActivity$SecondAsyncTask.onPostExecute(PartsActivity.java:980)
08-14 23:07:12.702: E/WindowManager(8623): at com.android.app.MyActivity$SecondAsyncTask.onPostExecute(PartsActivity.java:1)
08-14 23:07:12.702: E/WindowManager(8623): at android.os.AsyncTask.finish(AsyncTask.java:631)
08-14 23:07:12.702: E/WindowManager(8623): at android.os.AsyncTask.access$600(AsyncTask.java:177)
08-14 23:07:12.702: E/WindowManager(8623): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
. . . .
So what is the proper way of ending those excuted AysnTask when i press the cancel button in my ProgressDialog?