使用WKWebKit和Swift 3获取HTML元素值 [英] Get HTML element value using WKWebKit and Swift 3

问题描述

尝试使用WKWebView使用首选评估Javascript swift函数获取html元素名称或值。我继续收到零。我想也许我的函数在页面加载之前触发，因此永远不会找到元素。现在只是试图按类名获取元素文本。以下是我在ViewController中的代码

Trying to get an html element name or value using preferred evaluate Javascript swift function using a WKWebView. I keep recieving nil. I think maybe my function is firing before the page is loaded, thus never finding the element. Right now just trying to get the element text by class name. Here is my code below in the ViewController

    import UIKit
    import WebKit

    class ViewController: UIViewController, WKUIDelegate, WKNavigationDelegate {

        var web: WKWebView!

    override func loadView() {
        let webConfiguration = WKWebViewConfiguration()
        web = WKWebView(frame: .zero, configuration: webConfiguration)
        web.uiDelegate = self
        view = web
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        let url = URL(string: "http://www.appcoda.com")
        let myRequest = URLRequest(url: url!)
        web.load(myRequest)

        web.evaluateJavaScript("document.getElementByClassName('excerpt').innerText") {(result, error) in
            if error != nil {
                    print(String(describing:result))
            }
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

推荐答案

你部分正确。当您拨打 evaluateJavascript 时，网站将无法完成加载。但是还有其他错误：

You are partially right. The website won't finish loading by the time you call evaluateJavascript. But there are also other errors:

• 你应该设置 navigationDelegate 而不是 uiDelegate


• 由于App Transport Security，不允许对 http 地址的URL请求。如果网站支持，请使用 https 或正确配置您的应用程序。


• 您错误拼写了函数名称（缺少 getElement 之后的 s ）


• getElementsByClassName 返回一个数组，所以你必须选择你想要找到 innerText 的元素

• You should set the navigationDelegate instead of uiDelegate
• Due to App Transport Security, URL requests to http addresses are disallowed. Use https if the website supports it or configure your app appropriately.
• You misspelled the function name (missing the the s after getElement)
• getElementsByClassName returns an array so you have to pick what element you want to find the innerText of

试试这个：

override func viewDidLoad() {
    super.viewDidLoad()

    web = WKWebView(frame: .zero)
    web.navigationDelegate = self

    let url = URL(string: "https://www.appcoda.com")
    let myRequest = URLRequest(url: url!)
    web.load(myRequest)
}

func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    web.evaluateJavaScript("document.getElementsByClassName('excerpt')[0].innerText") {(result, error) in
        guard error == nil {
            print(error!)
            return
        }

        print(String(describing: result))
    }
}

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