根据ParentView自定义UIView类约束

import UIKit

class CustomView: UIView {
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupView()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setupView()
    }
    
    private func setupView() {
        // 设置视图的基本属性
        self.backgroundColor = UIColor.red
        self.layer.borderWidth = 1.0
        self.layer.borderColor = UIColor.black.cgColor
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        // 添加视图的布局约束
        self.translatesAutoresizingMaskIntoConstraints = false
        
        NSLayoutConstraint.activate([
            self.topAnchor.constraint(equalTo: superview!.topAnchor, constant: 20),
            self.leadingAnchor.constraint(equalTo: superview!.leadingAnchor, constant: 20),
            self.trailingAnchor.constraint(equalTo: superview!.trailingAnchor, constant: -20),
            self.heightAnchor.constraint(equalToConstant: 100)
        ])
    }
}

// 在ParentView中使用CustomView
class ParentView: UIView {
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupView()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setupView()
    }
    
    private func setupView() {
        // 添加CustomView到ParentView中
        let customView = CustomView()
        self.addSubview(customView)
        
        // 添加CustomView的布局约束
        customView.translatesAutoresizingMaskIntoConstraints = false
        
        NSLayoutConstraint.activate([
            customView.centerXAnchor.constraint(equalTo: self.centerXAnchor),
            customView.centerYAnchor.constraint(equalTo: self.centerYAnchor),
            customView.widthAnchor.constraint(equalToConstant: 200),
            customView.heightAnchor.constraint(equalToConstant: 200)
        ])
    }
}