Android Dialog not showing at all if called from a Timer Task

Question

timer = new Timer("Timer Thread");

    timer.scheduleAtFixedRate(new TimerTask() {
        @Override
        public void run() {
                showDialog(0);
                timeBar.setProgress(time);
            }
        }
    }, INTERVAL, INTERVAL);`

My onCreateDialog method is working fine, so when I use showDialog(0) from a Button it works fine. But not if the method is called by a Scheduler.

Answer 1

Using a handler:

protected static final int DIALOG_OK= 0;

timer = new Timer("Timer Thread");

timer.scheduleAtFixedRate(new TimerTask() {
    @Override
    public void run() {
            mDialogHandler.sendEmptyMessage(DIALOG_OK);
            timeBar.setProgress(time);
        }
    }
}, INTERVAL, INTERVAL);

 private Handler mDialogHandler = new Handler(){
            public void handleMessage(android.os.Message msg) {
                    switch (msg.what) {
                    case DIALOG_OK:
                            // We are now back in the UI thread
                            showDialog(0);
                    }

            };
    };

This allows you to call method's on the UI thread from other threads. Need more explanation, just ask.

Answer 2

You need to call these methods on the UI thread.

One way to do this is via AsyncTask, as in this answer.

Another way is to create a Handler and send messages to it from your TimerTask.

You can read more about AsyncTasc and the UI thread in Painless Threading.