实现UIView及其内部视图点击时像UIButton一样变暗

当然可以实现，下面给你两种实用的方案：

方案一：改用UIButton（最省心） #

既然要实现按钮的点击效果，直接用UIButton来承载图片和标签反而更省事，不用自己处理手势状态：

1. 创建自定义UIButton，设置背景为透明
2. 将图片和标签添加到button上，调整好布局
3. 利用button的highlighted状态实现变暗效果：
   • 给button添加半透明黑色遮罩视图，默认隐藏，在setHighlighted(_:)方法里控制遮罩的显示/隐藏
   • 也可以直接调整图片和标签的alpha值，高亮时设为0.6左右，恢复时设为1.0

示例代码：

class CustomButton: UIButton {
    let iconImageView = UIImageView()
    let titleLabel = UILabel()
    let highlightMask = UIView()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupViews()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setupViews()
    }
    
    private func setupViews() {
        backgroundColor = .clear
        
        // 添加图片和标签，此处省略布局代码，可使用AutoLayout或Frame实现
        addSubview(iconImageView)
        addSubview(titleLabel)
        
        // 添加高亮遮罩
        highlightMask.backgroundColor = UIColor.black.withAlphaComponent(0.2)
        highlightMask.isHidden = true
        highlightMask.frame = bounds
        highlightMask.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        addSubview(highlightMask)
    }
    
    override var isHighlighted: Bool {
        didSet {
            highlightMask.isHidden = !isHighlighted
            // 也可同时调整图片和标签透明度
            // iconImageView.alpha = isHighlighted ? 0.6 : 1.0
            // titleLabel.alpha = isHighlighted ? 0.6 : 1.0
        }
    }
}

方案二：自定义视图+手势处理状态 #

如果一定要用原有视图+UITapGestureRecognizer，可监听手势的不同状态切换视图效果：

1. 给视图添加半透明遮罩（或直接调整子视图的颜色/透明度）
2. 在手势began状态下激活变暗效果，ended/cancelled状态下恢复

示例代码：

class CustomTapView: UIView {
    let iconImageView = UIImageView()
    let titleLabel = UILabel()
    let highlightMask = UIView()
    private var originalImage: UIImage? // 保存原图片用于恢复
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupViews()
        addTapGesture()
        originalImage = iconImageView.image
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setupViews()
        addTapGesture()
        originalImage = iconImageView.image
    }
    
    private func setupViews() {
        backgroundColor = .clear
        
        addSubview(iconImageView)
        addSubview(titleLabel)
        // 省略布局代码
        
        highlightMask.backgroundColor = UIColor.black.withAlphaComponent(0.2)
        highlightMask.isHidden = true
        highlightMask.frame = bounds
        highlightMask.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        addSubview(highlightMask)
    }
    
    private func addTapGesture() {
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(_:)))
        addGestureRecognizer(tapGesture)
    }
    
    @objc private func handleTap(_ gesture: UITapGestureRecognizer) {
        switch gesture.state {
        case .began:
            // 开始点击时显示遮罩+图片变灰
            highlightMask.isHidden = false
            setImageViewGray(true)
        case .ended, .cancelled, .failed:
            // 结束点击时恢复原状
            highlightMask.isHidden = true
            setImageViewGray(false)
        default:
            break
        }
    }
    
    // 实现图片变灰效果
    private func setImageViewGray(_ isGray: Bool) {
        guard let originalImage = originalImage else { return }
        if isGray {
            let filter = CIFilter(name: "CIColorMonochrome")
            filter?.setValue(CIImage(image: originalImage), forKey: kCIInputImageKey)
            filter?.setValue(CIColor(red: 0.6, green: 0.6, blue: 0.6), forKey: kCIInputColorKey)
            filter?.setValue(1.0, forKey: kCIInputIntensityKey)
            let context = CIContext(options: nil)
            guard let outputImage = filter?.outputImage,
                  let cgImage = context.createCGImage(outputImage, from: outputImage.extent) else { return }
            iconImageView.image = UIImage(cgImage: cgImage)
        } else {
            iconImageView.image = originalImage
        }
    }
}

内容的提问来源于stack exchange，提问作者MaxSped