Question

I’m developing some kind of card game in which my view objects (cards, etc) are all CALayers. These objects are added as sublayers of a mainBoard (a CALayer), which, in turn, is a sublayer of the [UIView layer] property of my mainView. Everything is Ok, I can do hit testing to verify which layer is being touched through the touchesBegan:withEvent: callback of the mainView class normally, and so on.

However, I need to have a scroll inside my mainBoard to show “bigger” CALayers, so I tried first adding the “bigger” CALayer inside a CAScrollLayer, but I noticed that the CAScrollLayer doesn’t really scroll (doesn’t handle user input, neither draws scrollbars). So, the workaround would be to add an UIScrollView directly to the mainView UIView. The UIScrollView scrolls perfectly, until I try to add the “bigger” layer to it, by using [scrollView.layer addSublayer:<bigger layer>].

Does anyone has any idea of how I can have “scrollable” objects inside a CALayer?

Thanks!

Answer 1

nacho4d pointed the answer for my question.
Replying to mark: the “bigger” layer (a layer whose bounds is bigger than the area available in the screen (and so, needs to be contained in a scrollable area)).

The solution was to first wrap the “bigger” layer in a UIView:

UIView *wrapperView = ...
[wrapperView.layer addSublayer:<bigger_layer>];

afterwards, I can add the view as a subview of the UIScrollview:

[<uiscrollview> addSubview:wrapperView];

// set up scrolling properties
<uiscrollview>.contentSize = <bigger_layer>.frame.size;

The problem was that I was trying to add the “bigger” layer as a sublayer of the UIScrollview directly, instead, wrapping it in a UIView and adding it as a subview worked.

Thanks