TEAM LICENSES: Save money and learn new skills through a Hacking with Swift+ team license >>

How to force a UIView to redraw: setNeedsDisplay()

Swift version: 5.10

Paul Hudson    @twostraws   

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.

Hacking with Swift is sponsored by String Catalog.

SPONSORED Get accurate app localizations in minutes using AI. Choose your languages & receive translations for 40+ markets!

Localize My App

Sponsor Hacking with Swift and reach the world's largest Swift community!

Available from iOS 2.0

Similar solutions…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

BUY OUR BOOKS
Buy Pro Swift Buy Pro SwiftUI Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let us know!

Average rating: 3.6/5

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.