iOS 在视图中添加删除阴影

在iOS开发中，视图的阴影效果是一种常见的设计需求。通过为视图添加阴影，可以使界面看起来更加立体和有层次感。同时，通过动态地添加或删除阴影，还可以为用户提供更加丰富的交互体验。本文将介绍如何在iOS中 ，并添加案例代码，以实现在视图中添加或删除阴影的效果。

swift
let view = UIView(frame: CGRect(x: 100, y: 100, width: 200, height: 200))
view.backgroundColor = UIColor.white
let shadowLayer = CALayer()
shadowLayer.frame = view.bounds
shadowLayer.backgroundColor = UIColor.gray.cgColor
shadowLayer.shadowColor = UIColor.black.cgColor
shadowLayer.shadowOpacity = 0.5
shadowLayer.shadowOffset = CGSize(width: 0, height: 2)
shadowLayer.shadowRadius = 4
view.layer.addSublayer(shadowLayer)

swift
shadowLayer.removeFromSuperlayer()

swift
import UIKit
class ViewController: UIViewController {
    var viewWithShadow: UIView?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let button = UIButton(frame: CGRect(x: 100, y: 100, width: 200, height: 50))
        button.setTitle("Toggle Shadow", for: .normal)
        button.setTitleColor(.black, for: .normal)
        button.addTarget(self, action: #selector(toggleShadow), for: .touchUpInside)
        
        view.addSubview(button)
    }
    
    @objc func toggleShadow() {
        if let viewWithShadow = viewWithShadow {
            viewWithShadow.layer.shadowOpacity = 0
            viewWithShadow.removeFromSuperview()
            self.viewWithShadow = nil
        } else {
            let view = UIView(frame: CGRect(x: 100, y: 200, width: 200, height: 200))
            view.backgroundColor = .white
            
            let shadowLayer = CALayer()
            shadowLayer.frame = view.bounds
            shadowLayer.backgroundColor = UIColor.gray.cgColor
            shadowLayer.shadowColor = UIColor.black.cgColor
            shadowLayer.shadowOpacity = 0.5
            shadowLayer.shadowOffset = CGSize(width: 0, height: 2)
            shadowLayer.shadowRadius = 4
            
            view.layer.addSublayer(shadowLayer)
            self.viewWithShadow = view
            self.view.addSubview(view)
        }
    }
}