通过UIWebView进行双击识别 - Swift 3

Question

我正在尝试通过UIWebView实现Gesture识别器来检测双击。但没有人承认。

我已经浏览过网页上的一些教程，我可以编译到这个。代码如下。但没有成功。

class PageContentViewController: UIViewController, UIGestureRecognizerDelegate, UIWebViewDelegate  {

@IBOutlet weak var webView: UIWebView!

var pageIndex: Int = 0
var strTitle: String!
var flag : Int = 0

override func viewDidLoad() {
    super.viewDidLoad()
    webView.delegate = self

    DispatchQueue.main.async {
    let req = URLRequest(url: URL(fileURLWithPath: Bundle.main.path(forResource: self.strTitle+"/index" , ofType: "html")!))
    self.webView.loadRequest(req)
    self.view.addSubview(self.webView)

    }

    let tapGestureRecognizer = UITapGestureRecognizer(target:self, action:#selector(self.goToback))
    tapGestureRecognizer.delegate? = self
    tapGestureRecognizer.numberOfTapsRequired = 2
    webView.isUserInteractionEnabled = true
    webView.addGestureRecognizer(tapGestureRecognizer)
    webView.scrollView.addGestureRecognizer(tapGestureRecognizer)
    webView.gestureRecognizerShouldBegin(tapGestureRecognizer)
}


func gestureRecognizer(_: UIGestureRecognizer,  shouldRecognizeSimultaneouslyWith:UIGestureRecognizer) -> Bool {
    return true
}
func gestureRecognizer(_: UIGestureRecognizer, shouldReceive:UITouch) -> Bool {
    return true
}


func goToback(){
    print("On the Back")
}

}

代码有什么问题。？

我很快乐。

提前致谢

Answer 1

我认为你需要添加

webView.delegate = self

还要将UIWebViewDelegate添加到您的班级

编辑：

你的shouldRecognizeSimultaneouslyWith和shouldReceive看起来有点奇怪可能是一个复制粘贴错误？它应该看起来像：

func gestureRecognizer(_: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith:UIGestureRecognizer) -> Bool {
    return true
}
func gestureRecognizer(_: UIGestureRecognizer, shouldReceive:UITouch) -> Bool {
    return true
}

编辑2：

我复制了您的确切代码并删除了gestureRecognizerS应该开始并且它有效，我也能够删除其他一些代码，不确定您是否在项目中需要它但是这对我有用：

class ViewController: UIViewController, UIGestureRecognizerDelegate, UIWebViewDelegate  {

@IBOutlet weak var webView: UIWebView!

override func viewDidLoad() {
    super.viewDidLoad()
    webView.delegate = self

    DispatchQueue.main.async {
        let req = URLRequest(url: URL(fileURLWithPath: Bundle.main.path(forResource: self.strTitle+"/index" , ofType: "html")!))
        self.webView.loadRequest(req)
    }

    let tapGestureRecognizer = UITapGestureRecognizer(target:self, action:#selector(self.goToback))
    tapGestureRecognizer.delegate = self
    tapGestureRecognizer.numberOfTapsRequired = 2
    webView.isUserInteractionEnabled = true
    webView.addGestureRecognizer(tapGestureRecognizer)
}


func gestureRecognizer(_: UIGestureRecognizer,  shouldRecognizeSimultaneouslyWith:UIGestureRecognizer) -> Bool {
    return true
}


func goToback() {
    print("On the Back")
}

Answer 2

为什么对UIGestureRecognizer和webview使用相同的手势webview.scrollview。

相反，您需要为这两者创建两个单独的UIGestureRecognizer ...

// for webView
let tapGestureRecognizer = UITapGestureRecognizer(target:self, action:#selector(self.goToback))
tapGestureRecognizer.delegate? = self
tapGestureRecognizer.numberOfTapsRequired = 2
webView.isUserInteractionEnabled = true
webView.addGestureRecognizer(tapGestureRecognizer)

// for webView.scrollView
let tapGestureRecognizer1 = UITapGestureRecognizer(target:self, action:#selector(self.goToback))
tapGestureRecognizer1.delegate? = self
tapGestureRecognizer1.numberOfTapsRequired = 2
 webView.scrollView.addGestureRecognizer(tapGestureRecognizer1)

如果您为两个对象分配了相同的手势识别器，则其中一个对象没有它...请参阅日志

Answer 3

通过执行以下操作，我在我的应用中进行了双击手势：

我创建了一个UIWebView的子类，即UIGestureRecognizerDelegate

class MyWebView: UIWebView, UIGestureRecognizerDelegate {
    func gestureRecognizer(_: UIGestureRecognizer,  shouldRecognizeSimultaneouslyWith:UIGestureRecognizer) -> Bool {
        return true
    }

    func gestureRecognizer(_: UIGestureRecognizer, shouldReceive:UITouch) -> Bool {
        return true
    }
}

然后在我的View Controller类中，我引用了我的子类（确保它也在Interface Builder中引用）

@IBOutlet weak var webView: MyWebView!

在viewDidLoad中添加识别器

 let tapGestureRecognizer = UITapGestureRecognizer(target:self, action:#selector(self.goToback))
tapGestureRecognizer.delegate? = self.webView //set the delegate to the custom UIWebView
tapGestureRecognizer.numberOfTapsRequired = 2
webView.isUserInteractionEnabled = true
webView.addGestureRecognizer(tapGestureRecognizer)

希望这有帮助，我原来的代码是在Objective-C代码中，所以不得不在这里快速翻译，所以希望没有语法问题。

Answer 4

我已经使用过这段代码，它对我来说完美无缺

override func viewDidLoad() {
    super.viewDidLoad()

    let tapLockGesture = UITapGestureRecognizer(target: self, action: #selector(tapLock))    
    tapLockGesture.delegate = self
    tapLockGesture.numberOfTapsRequired = 2
    webView.addGestureRecognizer(tapLockGesture)

}

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return true
}

确保您符合 UIGestureRecognizerDelegate 和 UIScrollViewDelegate 。