CODEWITHSUNDEEP
iosobjective-cuiviewuitouch
user2572628
user2572628

Reputation: 21

What is the proper way of passing UITouch * across multiple subviews?

I have a custom view that has multiple subviews. They are all circles on the screen, sort of like three wheels of different radius on top of each other. I'm trying to make them receive a UITouch * event correctly to make them spin with the finger. Since the shapes are actually squares on the screen, when a bigger one flips and it's touchable area enters the frame of a circle above, it becomes untouchable.

So, I created another subview on top of others that will calculate the distance of the touch point to the center and distribute the touch event accordingly. I can think of several ways of doing it, but I was wondering what would be the most elegant, and most correct way of handling a situation like this.

This is what I've done so far: My custom view has a delegate, and that delegate is assigned to my main viewController. I have three protocol methods in my custom view, for the three wheels respectively. I'm passing out the touch and event according to the point of UITouch, but I'm not sure how should I actually send this data to the views that are supposed to receive it. They are all custom UIControl objects, and they all handle touches via the -beginTrackingWithTouch:withEvent:. Since this is a private method, I cannot access this from my viewController. Should I make this method public and access this from the viewController, or is there a more correct way of handling this?

Edit: added the code:

This is how I distribute the touch in the custom UIView object. The calculations work fine.

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    //Distribute the touches according to the touch location.
    UITouch *touch = [touches anyObject];
    CGPoint point = [touch locationInView:self];

    //calculations for the circles.
    CGFloat xDistance = (point.x - BIGGEST_CIRCLE_RADIUS);
    CGFloat yDistance = (point.y - BIGGEST_CIRCLE_RADIUS);
    CGFloat distance = sqrtf((xDistance*xDistance) + (yDistance*yDistance));

    //Check to see if the point is in one of the circles, starting from the innermost circle.
    if (distance <= SMALLEST_CIRCLE_RADIUS) {
        [self.delegate smallestCircleReceivedTouch:touch withEvent:event];
    } else if (distance < MIDDLE_CIRCLE_RADIUS) {
        [self.delegate middleCircleReceivedTouch:touch withEvent:event];
    } else if (distance <= BIGGEST_CIRCLE_RADIUS) {
        [self.delegate biggestCircleReceivedTouch:touch withEvent:event];
    } else {
        return;
    }
}

The delegate is the viewController and the circles are custom UIControls. They handle the touch like this:

- (BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event {

    CGPoint touchPoint = [touch locationInView:self];

    {....}

    return YES;
}

These work fine in themselves, but I'm not sure how should I connect the delegate method to the touch handling of each custom UIControl. Should I call their -beginTrackingWithTouch:withEvent: from the viewController, or should I make them implement the protocol of the customView? Or is there some other way to handle this properly?

Upvotes: 1

Views: 549

Answers (1)

Amin Negm-Awad
Amin Negm-Awad

Reputation: 16660

Even I did not try it, it is not necessary, to do your own calculation. -hitTest:withEvent: should work fine for you.

Upvotes: 1

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