Question

Today animateWithDuration was acting really stupid and I don’t know why really. I checked all the things, all the brackets and everything was perfect, but it was always presenting the line of code i didn’t specify as an animation.

Ok, so here’s the point. I have a longPressGestureRecognizer. It’s on some UIImageView, which is being dragged, after the longPress begins. When it ends in some special zone I want to start the animation, taking the UIImageView to some other place and finish it. Here’s my code:

if ([(UILongPressGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {
    CGPoint dropPoint = CGPointMake(self.center.x, self.center.y-5);
    for (UIView * placeForCharacter in delegate.subviews) {
        if ([placeForCharacter isKindOfClass:[PlaceForCharacterCircle class]]) {
            PlaceForCharacterCircle * newPlaceForCharacter = (PlaceForCharacterCircle *) placeForCharacter;
            if (CGRectContainsPoint(newPlaceForCharacter.dropZone, dropPoint)) {
                    UIViewAnimationOptions options = 0;
                    [UIView animateWithDuration:0.2 delay:0.0 options:0 animations:^{
                        self.frame = CGRectMake(newPlaceForCharacter.frame.origin.x-8, newPlaceForCharacter.frame.origin.y-5, 40, 55);
                        self.alpha = 0.5;
                    } 
                    completion:^(BOOL finished){
                        NSLog(@"animation completed");
                        self.alpha=1;
                        //code referring to the finalizing of moving, doesn't matter here
                        return;
                    }];
            } else {
                if (CGRectContainsPoint(newPlaceForCharacter.dropZone, dropPoint)) {
                    //code referring to the moving to the other place in case the UIImageView was dropped on another zone that is full already, doesn't matter here
                    return;
                }
            }
        }
    }
        //code referring to the comeback of a UIImageView in case it was dropped somewhere else, doesn't matter here
        //These two are the lines that get executed when the animation starts
        //THEY BEGIN
        translatedPoint = CGPointMake(initialX, initialY);
        [[sender view] setCenter:translatedPoint];
        //THEY END
        return;
}

The case is that for some strange reason the two lines of code above get animated instead of the REAL animation, that was specified. I double-checked it by putting the comments on these lines of code – in this case the animation works just fine.

Could someone please clear this out for me, why does this happen? It seems to be a really strange behaviour.

Answer 1

If you move the return; from the completion block (where it’s not doing anything) to after the animation is setup it should work.

[UIView animateWithDuration:0.2 delay:0.0 options:0 animations:^{
    self.frame = CGRectMake(newPlaceForCharacter.frame.origin.x-8, newPlaceForCharacter.frame.origin.y-5, 40, 55);
    self.alpha = 0.5;
}
completion:^{
    NSLog(@"animation completed");
    self.alpha=1;
    //code referring to the finalizing of moving, doesn't matter here
}];
return;