Android: ASyncTask's behavior contrary to documentation - recursion

Question

First time writing an AsyncTask and I seem to have a subtle design flaw that prevents both ProgressDialog, ProgressBar, and even Log.d() from working properly. I suspect that somehow I am not actually creating a new thread/task.
Short: the symptoms
A ProgressDialog is created in the constructor, and the code orders Android to show it in onPreExecute(), but the dialog never shows.
onProgressUpdate() is supposed to execute whenever I call publishProgress() from within doInBackground(), correct? Well, it doesn't. Instead, it executes when doInBackground() completes.
Long: investigations
Things I have verified through the emulator and, when possible, on a phone:
onPreExecute() is definitely called
the progress bar is not reset until after doInBackground() completes
update_dialog.show() is definitely executed, but the dialog does not appear unless I remove the .dismiss() in onPostExecute(); I imagine dialog is, like the progress bar, not shown until after doInBackground() completes, but is naturally immediately dismissed
the code will happily show dialogs when no computation is involved
doInBackground() definitely invokes publishProgress()
when it does, onProgressUpdate() does not execute immediately! that is, I have a breakpoint in the function, and the debugger does not stop there until after doInBackground() completes! (perhaps this is a phenomenon of the debugger, rather than doInBackground(), but I observe the same symptoms on a mobile device)
the progress bar gets updated... only after doInBackground() completes everything
similarly, the Log.d() data shows up in Android Monitor only after doInBackground() completes everything
and of course the dialog does not show up either in the emulator or on a device (unless I remove .dismiss() from onPostExecute())
Can anyone help find the problem? Ideally I'd like a working dialog, but as Android has deprecated that anyway I'd be fine with a working progress bar.
Code
Here are the essentials, less the details of computation &c.:
Where I call the AsyncTask from the main thread:
if (searching) { // this block does get executed!
Compute_Task my_task = new Compute_Task(overall_context, count);
my_task.execute(field, count, max_x, max_y);
try { result = my_task.get(); } catch (Exception e) { }
}
The AsyncTask itself:
private class Compute_Task extends AsyncTask<Object, Integer, Integer> {
public Compute_Task(Context context, int count) {
super();
current_positions = 0;
update_dialog = new ProgressDialog(context);
update_dialog.setIndeterminate(true);
update_dialog.setCancelable(false);
update_dialog.setTitle("Thinking");
update_dialog.setMessage("Please wait");
}
protected void onPreExecute() {
super.onPreExecute();
update_dialog.show();
ProgressBar pb = ((ProgressBar) ((Activity) overall_context).findViewById(R.id.progress_bar));
pb.setMax(base_count);
pb.setProgress(0);
}
protected void onPostExecute() {
super.onPostExecute();
update_dialog.dismiss();
}
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
ProgressBar pb = ((ProgressBar) ((Activity) overall_context).findViewById(R.id.progress_bar));
pb.setMax(base_count);
pb.incrementProgressBy(1);
Log.d(tag, values[0].toString());
}
protected Integer doInBackground(Object... params) {
Integer result = compute_scores(
(boolean[][]) params[0], (Integer) params[1], (Integer) params[2], (Integer) params[3], 0)
);
return result;
}
public int compute_scores(boolean[][] field, int count, int max_x, int max_y, int level) {
int result, completed = 0;
switch(count) {
// LOTS of computation goes on here,
// including a recursive call where all params are modified
if (level == 0)
publishProgress(++completed);
}
}
ProgressDialog update_dialog;
}

Answer 1

Turns out this is basically the same issue as the one given here. The "fatal" line is this one:
try { result = my_task.get(); } catch (Exception e) { }
Apparently this puts the UI thread into deep sleep. One should not use get() with an AsyncTask unless one is willing to suspend the UI thread. We have to perform a little magic in onPostExecute() instead.
Although it turns out that this was a duplicate, I didn't find it until after I wrote it, because I didn't realize the thread was blocking.