Swift version: 5.1
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:
That will ask UIKit to redraw the button using
drawRect(), but only if a redraw is not already queued.
SAVE 20% ON iOS CONF SG The largest iOS conference in Southeast Asia is back in Singapore for the 5th time in January 2020, now with two days of workshops plus two days of talks on SwiftUI, Combine, GraphQL, and more! Save a massive 20% on your tickets by clicking on this link.
Available from iOS 2.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.