when I have to do setNeedDisplay or setNeedLayout?

Question

When I do something on UIKit, I really want to ask a question.

when do I have to call setNeedsDisplay and when setNeedLayout?

Is this difficult to understand by reading the documentation? — Amar, Aug 12 '13 at 12:03

score 3 · Accepted Answer · answered Aug 12 '13 at 11:18

3

Calling setNeedDisplay forces the iOS to redraw. setNeedLayout forces layoutSubviews method to be called before next redraw.

answered Aug 12 '13 at 11:18

Vignesh

score 0 · Answer 2 · edited Aug 12 '13 at 12:13

You can check the Apple Documentation for this.

setNeedsLayout will layout subviews

Call this method on your application’s main thread when you want to adjust the layout of a view’s subviews.

setNeedsDisplay will call for a redraw of your view (drawRect:, etc).

You can use this method or the setNeedsDisplayInRect: to notify the system that your view’s contents need to be redrawn.

score -1 · Answer 3 · answered Aug 12 '13 at 11:20

-1

In simple terms

setNeedsDisplay : To redraw your view setNeedsLayout : To adjust positioning/sizing of your view

answered Aug 12 '13 at 11:20

Niru Mukund Shah

3 Answers3