I came up with a solution for this problem without any major workaround:
The basic idea how to maintain a progressdialog and a asynctask is described in this blogentry (of course I used the AsyncTaskComplex-Version). All credits go to the author of this blogentry, I only added a tiny thing:
Obviously I'm not using showDialog() anymore. Instead I stick with DialogFragments.
The second tweak is the importent one and also solves the problem with the IllegalStateException:
Instead of only telling the asynctask in onRetainCustomNonConfigurationInstance() that there is no more activity I also do it in onPause(). And instead of only telling the asynctask in onCreate() that there is a new activity I also do it in onResume().
And there you go, your AsyncTask will not try to inform your activity about his finish causing an IllegalStateException when the activity is not visible.
If you would like to see more code instead of words, leave a comment.
/edit:
Sourcecode to show my solution, which I think is a pretty decent one :)
public class MyActivity extends Activity {
private MyTask mTask;
@Override
protected void onCreate(Bundle pSavedInstanceState) {
super.onCreate(pSavedInstanceState);
setContentView(R.layout.editaccount);
Object retained = getLastCustomNonConfigurationInstance();
if ( retained instanceof NewContactFolderIdTask ) {
mTask = (MyTask) retained;
mTask.setActivity(this);
}
}
@Override
protected void onPause() {
if(mTask != null) {
mTask.setActivity(null);
}
super.onPause();
}
@Override
public Object onRetainCustomNonConfigurationInstance() {
if(mTask != null) {
mTask.setActivity(null);
return mTask;
}
return null;
}
@Override
protected void onResume() {
if(mTask != null) {
mTask.setActivity(this);
}
loadValues(); // or refreshListView or whatever you need to do
super.onResume();
}
public void onTaskCompleted() {
loadValues(); // or refreshListView or whatever you need to do
DialogFragment dialogFragment = (DialogFragment) getSupportFragmentManager().findFragmentByTag(PROGRESS_DIALOG_FRAGMENT);
if(dialogFragment != null) {
dialogFragment.dismiss();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater menuInflater = getMenuInflater();
menuInflater.inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// app icon in Action Bar clicked; go home
Intent intent = new Intent(this, OXClient.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
return true;
case R.id.menu_refresh:
mTask = new MyTask(this);
mTask.execute();
break;
}
return super.onOptionsItemSelected(item);
}
private class NewContactFolderIdTask extends AsyncTask<Boolean, Integer, Bundle> {
private MyActivity mActivity;
private boolean mCompleted;
private NewContactFolderIdTask(MyActivity pActivity) {
this.mActivity = pActivity;
}
public void setActivity(MyActivity pActivity) {
this.mActivity = pActivity;
if(mCompleted) {
notifiyActivityTaskCompleted();
}
}
private void notifiyActivityTaskCompleted() {
if(mActivity != null) {
mActivity.onTaskCompleted();
}
}
@Override
protected Bundle doInBackground(Boolean... pBoolean) {
// Do your stuff, return result
}
@Override
protected void onPreExecute() {
DialogFragment newFragment = ProgressDialogFragment.newInstance();
newFragment.show(getSupportFragmentManager(), PROGRESS_DIALOG_FRAGMENT);
}
@Override
protected void onPostExecute(Bundle pResult) {
mCompleted = true;
notifiyActivityTaskCompleted();
}
}
}
