将堆栈视图放在IOS屏幕的中央

Question

I am new in iOS application development. In my application I need a login form at the centre of the screen. I put all the elements in a UIStackView and that looks fine, but this UIStackView not align centred in all screens. How to make this UIStackView at the centre of screens.

Answer 1

如下面的屏幕截图所示，添加对齐约束，它将所​​有设备的堆栈视图对齐到屏幕中心

Answer 2

you can use viewDidLoad() , and viewWillTransitionToSize() to programmatically center the view. So Long as you have an IBOutlet bound to the stack view (called stackView in this example), this should work

stackView.frame.origin.x = view.frame.width/2 - stackView.frame.width/2
stackView.frame.origin.y = view.frame.height/2 - stackView.frame.width/2

just add this code in viewDidLoad and viewWillTransitionToSize() , depending if your program allows rotation, viewWillTransitionToSize() is optional. If you do use viewWillTransitionToSize() , there should be a parameter for size that you can replace view.frame with.

viewDidLoad() is called on startup, and viewWillTransitionToSize() is called whenever the phone is rotated, if you want that functionality.