aiuto di programmazione Java e lo sviluppo Android

Question

sto cercando di disegnare un'immagine su un'altra immagine quando un utente tocca lo schermo. Ma l'immagine appare solo quando i tocchi utente e poi scompare quando si lascia andare allo schermo.

Questa è la mia se il metodo:

int RED = 0;
int GREEN = 1;
Graphics g = game.getGraphics();
int len = touchEvents.size();

if (RED == 0) {
    ready = Assets.readybtntwo;
}

for(int i = 0; i < len; i++) {
    TouchEvent event = touchEvents.get(i);

    if(event.type == TouchEvent.TOUCH_UP){
        updateWaiting(touchEvents);
        RED +=1;

        if (RED == 0)
            ready = Assets.readybtntwo;

        if(RED == 1)
            ready = Assets.readybtngreentwo;
    }

    g.drawPixmap(ready, 0, 0);
}

Mi dispiace sto usando un framework integrato dal libro che inizia giochi Android. Ma non dovrebbe importare, voglio l'immagine di rimanere per sempre e se terminare il ciclo.

Answer 1

You have a logic error here. It looks like the variable RED is local to your method if the above code is all inside the touch event handler. This means that when the user touches the screen each time it's reset to 0 and then becomes 1 again. This probably isn't what you want.

The reason that it's only rendered is that g.drawPixmap will either be submitting an element to a draw queue or rendering it immediately. This method to draw the button is only ever being drawn when you have a touch event!

Instead, you could have a boolean drawGreenReadyButton value as a class member, i.e.

private boolean drawGreenReadyButton = false;

Then you can change that inner if statement to the following:

if(event.type == TouchEvent.TOUCH_UP){
    updateWaiting(touchEvents);
    drawGreenReadyButton = true;
}

And inside your main rendering loop rather than in the touch event handler put:

if(drawGreenReadyButton) {
    g.drawPixmap(Assets.readybtngreentwo, 0, 0);
} else {
    g.drawPixmap(Assets.readybtntwo, 0, 0);
}

Also, consider using TouchEvent.TOUCH_DOWN rather than TouchEvent.TOUCH_UP, so that the button is shown green as soon as they touch the screen, not when they lift their finger up.