How do I animate constraint changes?

Question

I\'m updating an old app with an AdBannerView and when there is no ad, it slides off screen. When there is an ad it slides on the screen. Basic stuff.

O

Answer 1

There is an article talk about this: http://weblog.invasivecode.com/post/42362079291/auto-layout-and-core-animation-auto-layout-was

In which, he coded like this:

- (void)handleTapFrom:(UIGestureRecognizer *)gesture {
    if (_isVisible) {
        _isVisible = NO;
        self.topConstraint.constant = -44.;    // 1
        [self.navbar setNeedsUpdateConstraints];  // 2
        [UIView animateWithDuration:.3 animations:^{
            [self.navbar layoutIfNeeded]; // 3
        }];
    } else {
        _isVisible = YES;
        self.topConstraint.constant = 0.;
        [self.navbar setNeedsUpdateConstraints];
        [UIView animateWithDuration:.3 animations:^{
            [self.navbar layoutIfNeeded];
        }];
    }
}

Hope it helps.