Making view resize to its parent when added with addSubview

Question

I\'m having a problem when using addSubview.

Example code:

ParentView *myParentView = [[ParentView alloc] initWithNibName:@\"ParentView \" bundle:nil         


        

Answer 1

Swift 4 extension using explicit constraints:

import UIKit.UIView

extension UIView {
    public func addSubview(_ subview: UIView, stretchToFit: Bool = false) {
        addSubview(subview)
        if stretchToFit {
            subview.translatesAutoresizingMaskIntoConstraints = false
            leftAnchor.constraint(equalTo: subview.leftAnchor).isActive = true
            rightAnchor.constraint(equalTo: subview.rightAnchor).isActive = true
            topAnchor.constraint(equalTo: subview.topAnchor).isActive = true
            bottomAnchor.constraint(equalTo: subview.bottomAnchor).isActive = true
        }
    }
}

Usage:

parentView.addSubview(childView) // won't resize (default behavior unchanged)
parentView.addSubview(childView, stretchToFit: false) // won't resize
parentView.addSubview(childView, stretchToFit: true) // will resize