Written by 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.
Available from iOS 2.0
Did this solution work for you? Please pass it on!
Other people are reading…
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Upgrade to premium
The Hacking with Swift guide book helps you learn faster, plus get an Xcode tips and tricks video and Swift wall chart.