CODEWITHSUNDEEP
iphonecocoauiviewtouchuiviewanimation
yinkou
yinkou

Reputation: 5766

Detect Touch on an animated View

I'm animating a couple of views with animateWithDuration: and i'm simply unable to detect any touches on them.

I've tried simple touch handling (touchesEnded:) and a tapGestureRecognizer.

First i've animated them with CGAffineTransformTranslation but then i realized that this won't if i check the coordinate with touchesMoved: so i switched to animate the frame property. I quickly noticed, that the frame values are not really changing during the animation so i dropped the touchesEnded: idea. So i changed to a tapGestureRecognizer which doesn't work too.

I've enabled userInteraction on all views and i also added the option UIViewAnimationOptionAllowUserInteraction to the animation.

Here's the code of the animation and the stuff that happens before: 

// init the main view
singleFingerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapOnItem:)]; // singleFingerTap is an ivar

// code somewhere:
// userItem is a subview of MainView
[userItem addGestureRecognizer:singleFingerTap];

[UIView animateWithDuration:animationTime
                      delay:0.0f
                    options:UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveLinear | UIViewAnimationOptionAllowUserInteraction
                 animations:^{
                     userItem.frame = CGRectMake(-(self.bounds.size.width + userItem.frame.size.width), userItem.frame.origin.y, userItem.frame.size.width, userItem.frame.size.height);
                 }

                 completion:^(BOOL finished) {
                     if (finished) {
                         [unusedViews addObject:userItem];
                         [userItem removeFromSuperview];
                         [userItem removeGestureRecognizer: singleFingerTap];
                     }
                 }
 ];

And here's the gesture recognizer: 

- (void) handleTapOnItem:(UITapGestureRecognizer *)recognizer{
   NSLog(@"Touched");
}

So how can i actually get a touch from an animated View or what is the best solution? Adding transparent uibutton to each view is not an option. :(

Upvotes: 2

Views: 1562

Answers (2)

David Rönnqvist
David Rönnqvist

Reputation: 56625

When an animation is applied to a view, the animated property changes to its end value right away. what you are actually seeing on screen is the presentation layer of your views layer.

I wrote a blog post about hit testing animating views/layers a while back that explain it all in more detail.

Upvotes: 3

WhoaItsAFactorial
WhoaItsAFactorial

Reputation: 3558

While anything is being moved using Core Animation touches on the object are halted until the object completes its movement. Interesting tid-bit, if you move the object and touch where its final location will be, the touch is picked up. This is because as soon as the animation is started the frame of the object is set to the ending point, it is not updated as it moves across the screen.

You might have to look into alternate technologies like Quartz or OpenGL ES to detect touches on your views as they are being moved.

Upvotes: 0

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