iOS持久视图图层值？

Question

I have an application where a user can drag many images onto a canvas. Some views are above other views. I want to save the images transforms, frames, and z-index. Where do I find the z-index of a view (in comparison with other views on the superview) so I can persist it. And then how to I restore all subviews to their proper z-index?

Answer 1

The superview have an array of child, into which the child are in order from back 0 to top (number of child) and there is method to insert child at a certain index.

There is a section of method in the UIView documentation with method that look like this one:

- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index

Answer 2

看起来你正在寻找视图层的（set / get） zPosition 。