IOS development-Where can I update the location information of the custom view subviews? (DrawRect: Or layoutSubviews ?), Subviewsdrawrect

IOS development-Where can I update the location information of the custom view subviews? (DrawRect: Or layoutSubviews ?), Subviewsdrawrect

For custom, you can add content through addSubview or draw content through Core Graphic.

 

For the latter, run in drawRect, And the location information is determined accordingly.

 

For the former, it is generally performed during the view initialization (or dynamically elsewhere). When setting the position information of the subview, you need to understand the following differences:

-In layoutSubviews, although the bounds of the custom view has been determined, the subview with constraint (such as the constraint added in the nib file ), its location information has not been updated according to the constraint.

-In drawRect:, the position of the subview has been updated according to the constraint.

That is to say, custom calls layoutSubviews, updates the location information of the subview, and then drawRect: