javascript - 无法读取未定义的属性 'messageHandlers'
<p><p>我想将 JavaScript 变量传递给 Swift。
我在 JavaScript 中遇到错误并进行搜索,但没有得到任何结果。
错误是:</p>
<blockquote>
<p>TypeError: Cannot read property 'messageHandlers' of undefined</p>
</blockquote>
<p>有人可以帮忙吗?</p>
<p>我在 Xcode 中的代码:</p>
<pre><code>import UIKit
import WebKit
class ViewController: UIViewController,WKScriptMessageHandler,WKNavigationDelegate {
var webView = WKWebView()
override func viewDidLoad() {
super.viewDidLoad()
webView.frame = view.bounds
webView.navigationDelegate = self
let url = URL(string: "MyUrl")!
let urlRequest = URLRequest(url: url)
webView.load(urlRequest)
webView.autoresizingMask = [.flexibleWidth,.flexibleHeight]
view.addSubview(webView)
let userContentController = WKUserContentController()
userContentController.add(self, name: "test")
}
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
print("Name: \(message.name)")
print("Body: \(message.body as! String)")
}
}
</code></pre>
<p>在 JavaScript 中:</p>
<pre><code>click: event => {
window.webkit.messageHandlers.test.postMessage("hi");
}
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>添加“测试”消息处理程序后,您需要将其添加到 <code>webView</code> 的配置中,但您没有这样做。</p>
<p>通过将此消息处理程序包含到您的 <code>WKUserContentController</code> 对象中,您的 webView 将定义一个可以调用的新函数 <code>window.webkit.messageHandlers.name.postMessage(messageBody)</code>在所有帧中。</p>
<p>尝试将您的 <code>viewDidLoad()</code> 更改为以下内容:</p>
<pre><code>override func viewDidLoad() {
super.viewDidLoad()
let config = WKWebViewConfiguration()
let userContentController = WKUserContentController()
userContentController.add(self, name: "test")
config.userContentController = userContentController
webView = WKWebView(frame: view.bounds, configuration: config) // Create webView with the configuration
webView.navigationDelegate = self
let url = URL(string: "MyUrl")!
let urlRequest = URLRequest(url: url)
webView.load(urlRequest)
webView.autoresizingMask = [.flexibleWidth,.flexibleHeight]
view.addSubview(webView)
}
</code></pre></p>
<p style="font-size: 20px;">关于javascript - 无法读取未定义的属性'messageHandlers',我们在Stack Overflow上找到一个类似的问题:
<a href="https://stackoverflow.com/questions/54745833/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/54745833/
</a>
</p>
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