How to force a UIView to redraw: setNeedsDisplay()
Swift version: 5.2
All views and subclasses are rendered using the drawRect() method, but you should never call that method directly yourself. Instead, it gets called by the system whenever drawing is required, which allows it to to avoid multiple redraws if drawRect() is called several times in a row.
Instead, if you want a view to redraw immediately, you should call its setNeedsDisplay() method like this:
myButton.setNeedsDisplay()That will ask UIKit to redraw the button using drawRect(), but only if a redraw is not already queued.
SPONSORED Building and maintaining in-app subscription infrastructure is hard. Luckily there's a better way. With RevenueCat, you can implement subscriptions for your app in hours, not months, so you can get back to building your app.
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS 2.0
Similar solutions…
- How to flip a UIView with a 3D effect: transition(with:)
- When is it safe to force unwrap optionals?
- How to force a view controller to use light or dark mode
- How to create custom text input using UIKeyInput
- How to force your program to crash with assert()
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
