Swift 将 GestureRecognizer 添加到 UIStackView 之上的 View答案

【问题标题】：Swift add GestureRecognizer to View on top of UIStackViewSwift 将 GestureRecognizer 添加到 UIStackView 之上的 View
【发布时间】：2020-02-02 17:04:38
【问题描述】：

我正在尝试将 GestureRecognizer 添加到 UIView，它是 UIStackView 的排列子视图。我已经试过这个this 或this。我还尝试为 userInteraction 启用所有底层视图，但没有成功。

当我将手势识别器添加到作为 stackView 的父视图的 imageView 时，点击会起作用。奇怪的是，当我点击作为 stackView 的子视图的“bannerView”时，它也会被触发，因此位于 imageView 的顶部。

在stackViews的arrangedSubview之上获得点击手势识别的正确方法是什么？

这是我的代码：

import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {
var imageView: UIImageView!
var bannerStackView: UIStackView!
var bannerView: UIView!

override func loadView() {
    let view = UIView()
    view.backgroundColor = .white
    self.view = view

    setupImageView()
    setupBannerStackView()
    setupConstraints()
}

func setupImageView() {
    let image = UIImage(named: "Apple.jpeg")
    imageView = UIImageView(image: image)
    imageView.backgroundColor = .red
    view.addSubview(imageView)
}

func setupBannerStackView() {
    bannerStackView = UIStackView()
    bannerStackView.axis = .vertical
    bannerStackView.alignment = .leading
    bannerStackView.distribution = .equalCentering
    bannerStackView.isUserInteractionEnabled = true

    bannerView = UIView()
    bannerView.backgroundColor = .blue

    bannerStackView.addArrangedSubview(bannerView)
    imageView.addSubview(bannerStackView)

    /*
     Also tried this but didn't work
     */
//        let tapGesture = UITapGestureRecognizer(target: self, action: 
#selector(onBannerTapped))
//        bannerView.isUserInteractionEnabled = true
//        bannerView.isUserInteractionEnabled = true
//        bannerView.addGestureRecognizer(tapGesture)

    for bannerView in bannerStackView.arrangedSubviews {
        let tapGesture = UITapGestureRecognizer(target: self, action: 
#selector(onBannerTapped))
        bannerView.isUserInteractionEnabled = true
        bannerView.addGestureRecognizer(tapGesture)
    }

}

@objc func onBannerTapped() {
    print("Banner view tapped!")
}

func setupConstraints() {
    imageView.translatesAutoresizingMaskIntoConstraints = false
    imageView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    imageView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
    imageView.widthAnchor.constraint(equalToConstant: 200).isActive = true
    imageView.heightAnchor.constraint(equalToConstant: 200).isActive = true

    bannerStackView.translatesAutoresizingMaskIntoConstraints = false
    bannerStackView.topAnchor.constraint(equalTo: imageView.topAnchor, constant: 10).isActive = true
    bannerStackView.leadingAnchor.constraint(equalTo: imageView.leadingAnchor).isActive = true

    bannerView.translatesAutoresizingMaskIntoConstraints = false
    bannerView.heightAnchor.constraint(equalToConstant: 30).isActive = true
    bannerView.widthAnchor.constraint(equalToConstant: 80).isActive = true
}
}

【问题讨论】：

我认为这行不通。因为有像“Z-stack”这样的东西，这意味着你只需要点击视图的顶部。所以你只能在视图顶部添加手势
查看我的代码，这正是我正在做的：将 GestureRecognizer 添加到最顶层视图的“bannerView”中。（只是我没有使用具有 Z-Stack 的 SwiftUI 实现）。任何其他想法可能有什么问题？

标签： swift uigesturerecognizer uistackview

【解决方案1】：

.isUserInteractionEnabled 级联到子视图。因此，即使我在子视图上将其设置为 true，如果子视图的父视图（或其父视图，以及在层次结构上）将 .isUserInteractionEnabled 设置为 false，子视图也不会获得触摸事件。

所以，首先要做的是检查层次结构中每个视图的.isUserInteractionEnabled。

在你的函数中，删除这一行：

    bannerStackView.isUserInteractionEnabled = true

然后在创建 tapGesture 后添加这些行：

    print("imageView isUserInteractionEnabled:", imageView.isUserInteractionEnabled)
    print("bannerStackView isUserInteractionEnabled:", bannerStackView.isUserInteractionEnabled)
    print("bannerView isUserInteractionEnabled:", bannerView.isUserInteractionEnabled)

所以它看起来像这样：

func setupBannerStackView() {
    bannerStackView = UIStackView()
    bannerStackView.axis = .vertical
    bannerStackView.alignment = .leading
    bannerStackView.distribution = .equalCentering

    // remove this line (comment-it out)
    // bannerStackView.isUserInteractionEnabled = true

    bannerView = UIView()
    bannerView.backgroundColor = .blue

    bannerStackView.addArrangedSubview(bannerView)
    imageView.addSubview(bannerStackView)

    let tapGesture = UITapGestureRecognizer(target: self, action: #selector(onBannerTapped))
    bannerView.addGestureRecognizer(tapGesture)

    print("view isUserInteractionEnabled:", view.isUserInteractionEnabled)
    print("imageView isUserInteractionEnabled:", imageView.isUserInteractionEnabled)
    print("bannerStackView isUserInteractionEnabled:", bannerStackView.isUserInteractionEnabled)
    print("bannerView isUserInteractionEnabled:", bannerView.isUserInteractionEnabled)

}

你应该看到这个输出：

view isUserInteractionEnabled: true
imageView isUserInteractionEnabled: false
bannerStackView isUserInteractionEnabled: true
bannerView isUserInteractionEnabled: true

这告诉你......你只需要添加：

imageView.isUserInteractionEnabled = true

【讨论】：