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iOS Build a Photo Browser iPhone App UIKit Dynamics Attaching Snap Behavior to Views

Posted by Brian Stevens
Brian Stevens
7,906 Points

Detail View Controller dismisses before UISnapBehavior completes.

Is anyone else running into this issue? I have tried to add resistance by adding a UIDynamicItemBehavior to my view (in this case, a button named "myPhoto"). But, that did not help either. Here's my code:

- (IBAction)dismissButtonTapped:(id)sender {
    self.animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];
    UIDynamicItemBehavior *resistance = [[UIDynamicItemBehavior alloc] initWithItems:@[self.myPhoto]];
    resistance.resistance = 1000.0f;
    [self.animator addBehavior:resistance];
    UISnapBehavior *snap = [[UISnapBehavior alloc] initWithItem:self.myPhoto
                                                    snapToPoint:CGPointMake(CGRectGetMidX(self.view.bounds), (CGRectGetMaxY(self.view.bounds) +180.0f))];
    [self.animator addBehavior:snap];
    [self.presentingViewController dismissViewControllerAnimated:YES completion:nil];
}

EDIT to add that if I comment out the code to dismiss the view controller, the snap behavior works as you would expect.

EDIT, again, to add that I found a work around using a half-second delay between the snap behavior and dismissing the view controller. But I have a feeling that this isn't the best way to do things.