iOS Animating main UIViewController's View height - ios

Question

I have a text field pinned to the bottom of my main UIViewController's view (self.view), and when the user clicks on it this function is called (via a UIKeyboardWillShowNotification) which will alter the height of the self.view.frame:
-(void)keyboardWillShow: (NSNotification*) notification {
NSDictionary* info = [notification userInfo];
CGSize keyboardSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
CGFloat textFieldHeight = activeField.frame.size.height;
CGPoint textFieldOrigin = activeField.frame.origin;
textFieldOrigin.y += textFieldHeight;
CGRect visibleRect = self.view.frame;
visibleRect.size.height -= keyboardSize.height;
if (!CGRectContainsPoint(visibleRect, textFieldOrigin)) {
CGRect r = self.view.frame;
r.size.height -= keyboardSize.height;
[UIView animateWithDuration:1.0
animations:^{
self.view.frame = r;
}];
}
}
It resizes the self.view.frame fine, so it is all being called and run, but for some reason refuses to animate it over a second - it just appears in place immediately.
What do I need to do in order to animate this change in height?

Answer 1

If you have auto layout on you shouldn't change the frame directly, instead you should change on of the constrains.
Add an IBOutlet to the constrain (the bottom constrain), and change the constant like so:
myTextFieldConstrain.constant -= YOUR_VALUE
Also, if you want it to animate, call [YOURSUPERVIEW layoutIfNeeded]; after you change the constant.
Example:
[UIView animateWithDuration:1.0
animations:^{
myTextFieldConstrain.constant -= YOUR_VALUE;
[YOURSUPERVIEW layoutIfNeeded];
}];

Answer 2

Try to dispatch it with a slight delay, like:
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 1 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
[UIView animateWithDuration:1.0
animations:^{
self.view.frame = r;
}];
}
It usually makes the trick.