[aspaans]

Hello everyone,

I'm writing a MIDlet that is a J2ME emulator of the old Casio FX7000 calculators.
The J2ME emulator executes a Casio program in a separate thread. This allows the user to cancel lengthy operations and looping programs and it keeps the user-interface responsive.

The interpreter that runs the program issues a Thread.yield() every time it moves to the next statement. This ensures that devices with cooperative-threading remain responsive. It all works pretty well, except for this:

Only when a Casio program is busy running: For example (on my Nokia3650) when I press the Menu-button, the menu does not appear (or when holding this button: the task-manager does not appear). Only after the program ends, suddenly the phone's menu appears. But all events (keypresses/paints) that are handled by the MIDlet itself arrive in time and are handled promptly.

When a Casio program is not running: Everything works fine (the interpreter-thread is waiting at the wait() statement).

Is there a way around this? What do i need to call? Thread.yield() does not work. Nor wait(timeout) or sleep(timeout)... I'd like to solve this, especially for the case when a Casio program is running and the user receives a phone-call.

// Simplified pseudo-code sample of the Runnable's run() method.

while (mActive)
{
    synchronized(this)
    {    
        wait(); // waiting until EXE button is pressed
        // The user pressed the EXE button. Run the program.
    }
    Interpreter.run(program);
    // done.
    ...
}

Interpreter.run(Program program)
{
    int i = 0;
    // Casio program about to be busy running.
    while (i < program.mStatements.size())
    {
        Thread.yield();

        ... execute(program.mStatements.get(i));
        ...

        i++;
    }
}

Instead of Thread.yield(), should I call something else?
Thanks!

[aspaans]

Update: When running on the emulator, these issues do not occur. Only when running on the real device.
I made some changes that allows a phone-call to come in or some other event to be handled promptly.

// Simplified pseudo-code sample of the Runnable's run() method.

while (mActive)
{
    synchronized(this)
    {    
        wait(); // waiting until EXE button is pressed
        // The user pressed the EXE button. Run the program.
    }
    Interpreter.run(program);
    // done.
    ...
}

Interpreter.run(Program program)
{
    int i = 0;
    // Casio program about to be busy running.
    while (i < program.mStatements.size())
    {
        Thread.yield();

        synchronized(mSyncer)
        {
            if (mHalted)
                mSyncer.wait();
        }

        ... execute(program.mStatements.get(i));
        ...

        i++;
    }
}

Interpreter.halt()
{
    synchronized(mSyncer)
    {
        mHalted = true;
    }
}

Interpreter.resume()
{
    synchronized(mSyncer)
    {
        mHalted = false;
        mSyncer.notify();
    }
}

Where the halt() and resume() are called when the canvas loses or gains focus (called from the hideNofity/showNotify and when switching displayables).

This still does not allow the Menu keypress to be handled promptly, but it will halt execution until the app gets focus again.

BTW: Is there a way to catch the Menu keypress on Series60 phones?