UIView auto layout slide in screen or out of screen animation - ios

Question

I can't figured it out how to do slide in/ out animation with auto layout.
I add constraints like this:
NSDictionary *viewsDic = #{#"tmpView" : tmpView};
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|[tmpView]|" options:0 metrics:nil views:viewsDic]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|[tmpView]|" options:0 metrics:nil views:viewsDic]];
[UIView animateWithDuration:.4 animations:^{
[self.view layoutIfNeeded];
}];
but this animates to grow from 0,0 position. how to achieve slide in/out animation?

Answer 1

As far as I understand, you need to get shift-effect. If my assumption is right, you need to manage horizontal or vertical padding manually during animation. And you need to get the reference on horizontal/vertical constraint:
#property (nonatomic, strong) NSLayoutConstraint *topPadding;
#property (nonatomic, strong) NSLayoutConstraint *heightConstraint;
Adding a constraint with initial value so that tmpView is out of visible part of its superview:
self.heightConstraint = [NSLayoutConstraint constraintWithItem:tmpView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1.0
constant:0.0];
self.topPadding = [NSLayoutConstraint constraintWithItem:tmpView
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeTop
multiplier:1.0
constant:self.view.bounds.size.height];
[self.view addConstraint:self.topPadding];
[self.view addConstraint:self.heightConstraint];
Then we need simply to show tmpView with animation:
[self.view layoutIfNeeded];
[UIView animateWithDuration:.4 animations:^{
self.topPadding.constant = 0.0;
self.heightConstraint.constant = self.view.bounds.size.height;
[self.view layoutIfNeeded];
}];
Whit this example tmpView appears from the bottom.
Please ensure that self.topPadding won't conflict with other you constraints
To hide the view you can use something like this:
[self.view layoutIfNeeded];
[UIView animateWithDuration:.4 animations:^{
self.topPadding.constant = self.superview.bounds.size.height;
[self.view layoutIfNeeded];
}];
UPD.: Sometimes you also need to add hight constraints as well. Added use of self.heightConstraint in my example
UPD.: You still need horizontal constraints.
Please leave these lines:
NSDictionary *viewsDic = #{#"tmpView" : tmpView};
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|[tmpView]|" options:0 metrics:nil views:viewsDic]];