Animate view height with Swift

Question

I have view sView inside my ViewController. It height has constraint - I created IBOutlet for this constraint - sViewHeightConstraint. I want to decrease height of sView with animation.

I created function

UIView.animateWithDuration(5.5, animations: {
                self.sViewHeightConstraint.constant = 50
            })

Height of view is changing but i don't see any animation. What I am doing wrong?

score 75 · Accepted Answer · edited Apr 02 '17 at 03:47

75

use layoutIfNeeded()

 view.layoutIfNeeded() // force any pending operations to finish

 UIView.animateWithDuration(0.2, animations: { () -> Void in
    self.sViewHeightConstraint.constant = 50
    self.view.layoutIfNeeded()
})

swift 3

view.layoutIfNeeded() 
sViewHeightConstraint.constant = 50

UIView.animate(withDuration: 1.0, animations: { 
     self.view.layoutIfNeeded() 
})

edited Apr 02 '17 at 03:47

Elijah

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answered Apr 30 '16 at 10:07

Bhavin Bhadani

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@moonvader `layoutIfNeeded` on the view force any pending operations to finish and then in the animation block capture the frame changes. – Bhavin Bhadani Apr 30 '16 at 10:14
for more info. check http://stackoverflow.com/questions/1182945/how-is-layoutifneeded-used – Bhavin Bhadani Apr 30 '16 at 10:24

score 0 · Answer 2 · answered Feb 11 '22 at 03:52

In case your view updates but animation isn't working, this solution works for me.

UIView.animate(withDuration: 0.2, animations: { 
    self.sViewHeightConstraint.constant = 50
    self.sView.size = CGSize(width: self.sView.frame.width, height: 50)
    self.view.layoutIfNeeded() 
})

Animate view height with Swift

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