在 UIWebView 中向后/向前滑动手势？

Question

我的应用中有一个 WebView。

因为它是一个选项卡式应用程序，我无法在网站上添加返回/前进按钮。

我想通过滑动来后退/前进。从左侧/边缘向右滑动又回来了……就像在 iOS 的 Safari 浏览器中一样。

我该怎么做？我想我应该使用“屏幕边缘平移手势识别器”，对吧？

Answer 1

在 Swift 3 中接受的答案：

override func viewDidLoad() {
    super.viewDidLoad()

    let swipeLeftRecognizer = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipe(recognizer:)))
    let swipeRightRecognizer = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipe(recognizer:)))
    swipeLeftRecognizer.direction = .left
    swipeRightRecognizer.direction = .right

    webView.addGestureRecognizer(swipeLeftRecognizer)
    webView.addGestureRecognizer(swipeRightRecognizer)
}

@objc private func handleSwipe(recognizer: UISwipeGestureRecognizer) {
    if (recognizer.direction == .left) {
        if webView.canGoForward {
            webView.goForward()
        }
    }

    if (recognizer.direction == .right) {
        if webView.canGoBack {
            webView.goBack()
        }
    }
}

Answer 2

在 Swift 3 和 Swift 4 中回答

如果有人仍然有问题。这对我有用：

找到“didFinish”添加/替换以下代码。

func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {

    self.didFinish()

    webView.allowsBackForwardNavigationGestures = true

}

您需要的主要代码只有一行。它位于 self.didFinish() 之后，但仍在 {} 括号内。

webView.allowsBackForwardNavigationGestures = true

Answer 3

为什么不直接使用滑动手势识别器？

UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)];
UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)];

// Setting the swipe direction.
[swipeLeft setDirection:UISwipeGestureRecognizerDirectionLeft];
[swipeRight setDirection:UISwipeGestureRecognizerDirectionRight];

// Adding the swipe gesture on WebView
[webView addGestureRecognizer:swipeLeft];
[webView addGestureRecognizer:swipeRight];

- (void)handleSwipe:(UISwipeGestureRecognizer *)swipe {

if (swipe.direction == UISwipeGestureRecognizerDirectionLeft) {
    NSLog(@"Left Swipe");
}

if (swipe.direction == UISwipeGestureRecognizerDirectionRight) {
    NSLog(@"Right Swipe");   
} 

}

Answer 4

Gabriel Madruga 的回答对我有用。我通过以下方式进一步减少了代码行数：

1. 将 WebView 拖放到情节提要中。应用所需的约束。
2. 声明 WebView 的 IBOutlet。我将它命名为 webViewBox。
3. 导入 WebKit 框架。 （导入 WebKit）

4. 在 viewDidLoad() 中添加以下代码

   let leftSwipe = UISwipeGestureRecognizer(target: webViewBox, action: #selector(webViewBox.goForward))
   leftSwipe.direction = .left
   webViewBox.addGestureRecognizer(leftSwipe)
   
   let rightSwipe = UISwipeGestureRecognizer(target: webViewBox, action: #selector(webViewBox.goBack))
   leftSwipe.direction = .right
   webViewBox.addGestureRecognizer(rightSwipe)
   

您的最终结果应如下所示：

    import UIKit
    import WebKit

    class ViewController: UIViewController {


@IBOutlet weak var webViewBox: WKWebView!

override func viewDidLoad() {
    super.viewDidLoad()


    //URL request:
    let urlReq = URLRequest(url: URL(string: "https://www.google.co.in")!)
    //Load the URL:        
    webViewBox.load(urlReq)



    //To go forward:
    let leftSwipe = UISwipeGestureRecognizer(target: webViewBox, action: #selector(webViewBox.goForward))
    leftSwipe.direction = .left
    webViewBox.addGestureRecognizer(leftSwipe)

    //To go back:
    let rightSwipe = UISwipeGestureRecognizer(target: webViewBox, action: #selector(webViewBox.goBack))
    rightSwipe.direction = .right
    webViewBox.addGestureRecognizer(rightSwipe)
  }
}