Auto Layout constraint on CALayer IOS

the whole autoresizing business is view-specific. layers don't autoresize.

what you have to do -- in code -- is to resize the layer yourself

e.g.

in a viewController you would do

- (void) viewDidLayoutSubviews {  [super viewDidLayoutSubviews]; //if you want superclass's behaviour...   // resize your layers based on the view's new frame  self.editViewBorderLayer.frame = self.editView.bounds;}

or in a custom UIView you could use

- (void)layoutSubviews {  [super layoutSubviews]; //if you want superclass's behaviour...  (and lay outing of children)  // resize your layers based on the view's new frame  layer.frame = self.bounds;}

In Swift 5, you can try the following solution:

Use KVO, for the path "YourView.bounds" as given below.

self.addObserver(self, forKeyPath: "YourView.bounds", options: .new, context: nil)

Then handle it as given below.

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {        if keyPath == "YourView.bounds" {            YourLayer.frame = YourView.bounds            return        }        super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)    }

More info about this here

According to this answer, layoutSubviews does not get called in all needed cases. I have found this delegate method more effective:

- (instancetype)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if(self != nil) {        [self.layer addSublayer:self.mySublayer];    }    return self;}- (void)layoutSublayersOfLayer:(CALayer*)layer{    self.mySublayer.frame = self.bounds;}