When I Added rightAnchor constraint, constant= 20 did not apply. In leftAnchor is ok
override init(frame: CGRect) {
super.init(frame: frame)
addSubview
I have a really strong feeling that this is what you wanted to do there for rightAnchor
.
collectionView.rightAnchor.constraint(equalTo: rightAnchor, constant: -20)
If you want padding from the right or bottom you should use negative values.
Rule of thumb: Whatever is left or upwards of something is negative.