iOS Auto Layout Mixed usage of Auto Layout with non-Auto Layout


Example

Sometimes you may want to perform some additional actions to Auto Layout calculations done by UIKit itself.

Example: when you have a UIView that has a maskLayer, you may need to update maskLayer as soon as Auto Layout changes UIView's frame

// CustomView.m
- (void)layoutSubviews {
    [super layoutSubviews];
    // now you can assume Auto Layout did its job
    // you can use view's frame in your calculations
    CALayer maskLayer = self.maskLayer;
    maskLayer.bounds = self.bounds;
    ...
}

or if you want to take some additional action to Auto Layout in ViewController

- (void)viewDidLayoutSubviews {
    [super viewDidLayoutSubviews];
    // now you can assume all your subviews are positioned/resized correctly
    self.customView.frame = self.containerView.frame;
}