How to programmatically increase the height of UIView with Swift
You need to create an outlet for the height constraint of the detail view, and then you can adjust the height programmatically like this myHeightConstraint.constant += extraHeight
where extraHeight
is a number indicating how much taller you want the detail view to be. You also may need to call self.view.layoutIfNeeded()
afterwards.
To create an outlet from a constraint, control drag from the constraint in the storyboard editor (just like you would for an outlet of a UIView) into your code.
You are right - because you are using auto layout and constraints, the adjustments need to be made with constraints too. Setting the raw frames can lead to unexpected behavior. Let me know if you have any other questions or difficulties.
Inside the CGRect
initializer you should not be using +=
, just +
.
Change:
self.view.frame = CGRect(x: 0, y: 0, width: self.view.frame.width, height: self.view.frame.height += 20.0)
to:
self.view.frame = CGRect(x: 0, y: 0, width: self.view.frame.width, height: self.view.frame.height + 20.0)
You should not be trying to change the value of self.view.frame.height
inside the initializer.
Swift 4.2
I create an example for you programmatically:
var flowHeightConstraint: NSLayoutConstraint? override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .white view.addSubview(button) button.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true button.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true button.widthAnchor.constraint(equalToConstant: 100).isActive = true flowHeightConstraint = button.heightAnchor.constraint(equalToConstant: 30) flowHeightConstraint?.isActive = true } @objc func animateButtonTapped() { UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseOut, animations: { self.flowHeightConstraint?.constant = 100 self.view.layoutIfNeeded() }, completion: nil) } lazy var button: UIButton = { let button = UIButton() button.translatesAutoresizingMaskIntoConstraints = false button.backgroundColor = .green button.addTarget(self, action: #selector(animateButtonTapped), for: .touchUpInside) return button }()
this line of code create a button an on tapped change height of button with animation.
hope this help :)