继承约束的 Swift 继承

Question

在下面的快速代码中，我尝试使用继承。当我去上课时，初始视图控制器上的约束仍在应用中。即使在中产阶级中我尝试将新的约束附加到右键，它们也没有被应用。您可以在下面的照片中看到问题所在。

import UIKit

class ViewController: UIViewController {
    
    var right = UIButton()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        [right].forEach{
            $0.translatesAutoresizingMaskIntoConstraints = false
            view.addSubview($0)
            $0.backgroundColor = UIColor(
                red: .random(in: 0.0...1),
                green: .random(in: 0.9...1),
                blue: .random(in: 0.7...1),
                alpha: 1
            )
        }
        
        NSLayoutConstraint.activate([

            right.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            right.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            right.heightAnchor.constraint(equalTo: view.heightAnchor,multiplier: 0.1),
            right.widthAnchor.constraint(equalTo: view.widthAnchor,multiplier: 1),
            
            
        ])
        right.setTitle(">", for: .normal)
        right.addTarget(self, action: #selector(nexte), for: .touchDown)
    }
    
    
    @objc func nexte(){
        
        let vc = middle()
        vc.modalPresentationStyle = .overCurrentContext // actually .fullScreen would be better
        self.present(vc, animated: true)
        
    }
    
}


class middle : ViewController{
    
    var leftbtn = UIButton()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        [leftbtn].forEach{
            $0.translatesAutoresizingMaskIntoConstraints = false
            view.addSubview($0)
            $0.backgroundColor = UIColor(
                red: .random(in: 0.0...1),
                green: .random(in: 0.9...1),
                blue: .random(in: 0.7...1),
                alpha: 1
            )
            
        }
        
        NSLayoutConstraint.activate([
            
            leftbtn.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            leftbtn.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            leftbtn.heightAnchor.constraint(equalTo: view.heightAnchor,multiplier: 0.1),
            leftbtn.widthAnchor.constraint(equalTo: view.widthAnchor,multiplier: 0.5 ),
            
            right.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            right.leadingAnchor.constraint(equalTo: leftbtn.trailingAnchor),
            right.heightAnchor.constraint(equalTo: view.heightAnchor,multiplier: 0.1),
            right.widthAnchor.constraint(equalTo: view.widthAnchor,multiplier: 0.5 ),
            
        ])
        
    }
}

Answer 1

你在中间说super.viewDidLoad()。 super 是 ViewController 所以 ViewController 的 viewDidLoad 也会被执行。因此“当我去上课时，初始视图控制器上的约束仍在应用中”。

您应该在这里重新考虑您的整个架构。