Re: Plea for assistance...

Hi again,

> Could you explain a bit what you're trying to do?

I am experiencing difficulties where a user will hit a key repeatedly and my
MIDlet will start processing the second keyPress before it has finished
processing the first one.

> If you're processing
> key events I'll assume you have a Canvas that wants to do something in
> response to a key press.

OK, but it's quite complicated (well, for me anyway :)). I just wanted some
info on keypressed stuff. Here goes anyway...

... in my Canvas object...
... in the keyPressed method...

case STATE_GAME_REPORT:
        // New little check to stop key hammering bug...
        if (!playAgainHit) {
                playAgainHit = true;
                midlet.playAgain();
        } return;

...

If I hit the keys fast enough (occurs on either emulator or phone), then bad
things happen. It's difficult to describe, but here goes anyway...

Two keys are pressed in quick succession. The check above is supposed to
ensure that playAgain gets called once and only once. This fails sometimes
because the first keypress event arrives, sees that playAgainHit is false,
sets it to true, is about to call midlet.playAgain()... but this never gets
called, as the second keypress has arrived, and interrupts the first one.
This second keypressed event finds that playAgainHit is false, so the
midlet.playAgain() call never happens.

All verified using System.out.println's in the emulator (which may not be
the most reliable bit of evidence).

To fix this problem, I added the following to the start of the paint method
(yes, I know it's nasty, but)...

// If someone's hammering the keys, then give the
// phone a bit of time, then reset it. That'll learn 'em :)
if (playAgainHit) {
  Timer timer = new Timer();
  TimerTask task = new TimerTask() {
    public void run() {
      playAgainHit = false;
    }
  };
  timer.schedule(task, 1500);
}

> Just elaborate what it is you're trying to do
> and we can tell you how to do it.

I'm trying to make my MIDlet run normally when users hammer the keys, or at
least find out a bit more on how MIDlets process key events.


Tim writes:

> These methods are all called serially. That is, the
> implementation will never call an event delivery method before a
> prior call to any of the event delivery methods has returned."
>
> This is pulled word for word from the Canvas class description
> under the Event Delivery heading.  I would say that this is a bug
> in the VM.  (Unless I am missing something.)

I assumed they are all called serially, which is why I'm finding this bug so
hard to figure out. This occurs on Nokia series 40 and 60 phones and the
related emulators, also on the Motorola T720 and Samsung C100. I have a
horrible feeling it's something I've done, but have looked everywhere else.
I just wanted to know if this was how things were handled by the
specification (and it appears so).

Many thanks for your replies,


Adrian.


Adrian Hill
Software Architect
NRMi

Phone: +44 (0)1482 441142
Web: http://www.nrmi.co.uk

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