添加手势识别器到uiimage

Question

我有图像滑块..我按照本教程来做：Create a Horizontal Paging UIScrollView with UIPageControl Swift 4 XCode 9，它的工作完美..

现在我想在这些图像上添加手势识别器..我试着这样做：

func createSlides() -> [banner] {

    let tapGesture = UITapGestureRecognizer(target: self, action: #selector(tapped))
    tapGesture.numberOfTapsRequired = 1
    tapGesture.numberOfTouchesRequired = 1

    let slide1:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
    slide1.img.image = UIImage(named: "bannerex")
    slide1.img.addGestureRecognizer(tapGesture)

    let slide2:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
    slide2.img.image = UIImage(named: "bannerex")
    slide2.img.addGestureRecognizer(tapGesture)

    let slide3:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
    slide3.img.image = UIImage(named: "bannerex")
    slide3.img.addGestureRecognizer(tapGesture)

    return [slide1, slide2, slide3]
}

@objc func tapped(_ sender: UITapGestureRecognizer){
    print("tapped")
    print(pageControl.currentPage)
}

但它不起作用，什么都不会发生。

如何解决这个问题？

import UIKit

class banner: UIView {


@IBOutlet weak var img: UIImageView!

 }

Answer 1

这里有两个问题：

1. isUserInteractionEnabled默认是false
2. 你必须为每个图像视图分配一个单独的手势识别器

---

解

我没有为每个图像视图单独设置isUserInteractionEnabled到true，我建议将该代码放在Banner类本身。由于您似乎是从故事板初始化它，使用awakeFromNib函数应该可以正常工作：

class Banner: UIView {

    @IBOutlet weak var img: UIImageView!

    override func awakeFromNib() {
        super.awakeFromNib()
        img.isUserInteractionEnabled = true
    }
 }

在createSlides()函数中，为每个视图添加单独的点按手势：

let slide1:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
slide1.img.image = UIImage(named: "bannerex")
slide1.img.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(tapped)))

甚至更好的缩放和无代码冗余：

function tap() -> UITapGestureRecognizer {
    return UITapGestureRecognizer(target: self, action: #selector(tapped))
}

let slide1:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
slide1.img.image = UIImage(named: "bannerex")
slide1.img.addGestureRecognizer(tap())

Answer 2

UITapGestureRecognizer必须只使用一个视图，因此如果你想检测每个UITapGestureRecognizer上的点击，你需要为每个图像创建不同的image。阅读更多HERE。

你需要为每个isUserInteractionEnabled设置true到imageView。

Answer 3

Image views默认忽略用户事件。如果您还希望图像视图处理用户交互，请将其isUserInteractionEnabled属性的值更改为true。