Question

I have made an app and i want to make it multi touch compatible. i have tried looking around but the answers aren’t specific to mine.
Here is what i do:

1) My coding:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

[self touchesMoved:touches withEvent:event];
if (gameState == kGameStatePaused) {(gameState = kGameStateRunning);}
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
if(gameState == kGameStateRunning) {

    UITouch *touch = [[event allTouches] anyObject];
    CGPoint location = [touch locationInView:touch.view];
    if(location.x > 400) {

        CGPoint yLocation = CGPointMake(playerPaddle.center.x, location.y);
        playerPaddle.center = yLocation;
    }

    if (gameStyle == kGameStyleTwoP) {
        if(location.x < 100) {

            CGPoint yLocation2 = CGPointMake(computerPaddle.center.x, location.y);
            computerPaddle.center = yLocation2;
        }
    }
}

2) I have gone onto Interface Builder and checked the box for multitouch enabled

3) I build and run my app and it opens properly and when i go to test the multitouch i hold “option key” and click and move the mouse

4) (i am trying to make computerPaddle and playerPaddle both move) but only one of the works at a time

I have to tried to fix it but i can’t understand where i am going wrong.

Any help is useful.
THX.

Answer 1

look this line

UITouch *touch = [[event allTouches] anyObject];

you only take one touch and ignore rest and thats why only one thing can move

so replace with a for loop should fix the problem

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
if(gameState == kGameStateRunning) {

    for (UITouch *touch in [event allTouches]) {
    CGPoint location = [touch locationInView:touch.view];
    if(location.x > 400) {

        CGPoint yLocation = CGPointMake(playerPaddle.center.x, location.y);
        playerPaddle.center = yLocation;
    }

    if (gameStyle == kGameStyleTwoP) {
        if(location.x < 100) {

            CGPoint yLocation2 = CGPointMake(computerPaddle.center.x, location.y);
            computerPaddle.center = yLocation2;
        }
    }
}
}