CALayers didn't get resized on its UIView's bounds change. Why?

Question

I have a UIView which has about 8 different CALayer sublayers added to its layer. If I modify the view's bounds (animated), then the view itself shrinks (I checked it with a backgroundColor), but the sublayers' size remains unchanged.

How to solve this?

Answer 1

I used the same approach that Solin used, but there's a typo in that code. The method should be:

- (void)layoutSubviews {
  [super layoutSubviews];
  // resize your layers based on the view's new bounds
  mylayer.frame = self.bounds;
}

For my purposes, I always wanted the sublayer to be the full size of the parent view. Put that method in your view class.

Answer 2

Since CALayer on the iPhone does not support layout managers, I think you have to make your view's main layer a custom CALayer subclass in which you override layoutSublayers to set the frames of all sublayers. You must also override your view's +layerClass method to return the class of your new CALayer subclass.

Answer 3

I used this in the UIView.

-(void)layoutSublayersOfLayer:(CALayer *)layer
{
    if (layer == self.layer)
    {
        _anySubLayer.frame = layer.bounds;
    }

super.layoutSublayersOfLayer(layer)
}

Works for me.

Answer 4

I had the same problem. In a custom view's layer I added two more sublayers. In order to resize the sublayers (every time the custom view's boundaries change), I implemented the method layoutSubviews of my custom view; inside this method I just update each sublayer's frame to match the current boundaries of my subview's layer.

Something like this:

-(void)layoutSubviews{
   //keep the same origin, just update the width and height
   if(sublayer1!=nil){
      sublayer1.frame = self.layer.bounds;
   }
}