ios UIWebView 委托方法 shouldStartLoadWithRequest：等效于 WKWebView？

UIWebView delegate method shouldStartLoadWithRequest: equivalent in WKWebView?

提问by invalidArgument

I have a module inside my iOS 7+ app which is a UIWebView. The html page loads a javascript that creates custom-shaped buttons (using the Raphaeljs library). With UIWebView, I set delegate to self. The delegate method webView: shouldStartLoadWithRequest: navigationType:is called each time one of my custom button is pressed. The requests should not be handled by the html, but rather by the iOS code. So I used a request convention (read somewhere here on stackoverflow) using "inapp" as the scheme of my requests. I then check for the host and take the appropriate action.

我的 iOS 7+ 应用程序中有一个模块，它是一个 UIWebView。html 页面加载一个创建自定义形状按钮的 javascript（使用 Raphaeljs 库）。使用 UIWebView，我将委托设置为 self。webView: shouldStartLoadWithRequest: navigationType:每次按下我的自定义按钮之一时都会调用委托方法。请求不应由 html 处理，而应由 iOS 代码处理。所以我使用了一个请求约定（在 stackoverflow 上的某处阅读），使用“inapp”作为我的请求方案。然后我检查主机并采取适当的措施。

This code works fine on iOS 7. But the web views appear blank on iOS 8 (bug?), so I decided to use WKWebView for iOS 8 devices. The web views now render fine (and amazingly faster!), but my buttons have no effect.

此代码在 iOS 7 上运行良好。但 Web 视图在 iOS 8 上显示为空白（错误？），因此我决定将 WKWebView 用于 iOS 8 设备。Web 视图现在渲染得很好（而且速度快得惊人！），但我的按钮没有效果。

I tried using - (WKNaviation *)loadRequest:(NSURLRequest *)request, but it's not called.

我尝试使用- (WKNaviation *)loadRequest:(NSURLRequest *)request，但它没有被调用。

I can't find a direct equivalent of the UIWebView delegate method webView: shouldStartLoadWithRequest: navigationType:. What's the best way of handling those requests with WKWebView?

我找不到 UIWebView 委托方法的直接等价物webView: shouldStartLoadWithRequest: navigationType:。使用 WKWebView 处理这些请求的最佳方式是什么？

采纳答案by SeanR

Re-reading your description it looks like what you actually need to know about is how to reimplement a Javascript/Objective-C bridge using WKWebView.

重新阅读您的描述，看起来您真正需要了解的是如何使用 WKWebView 重新实现 Javascript/Objective-C 桥。

I've just done this myself, following the tutorial at http://tetontech.wordpress.com/2014/07/17/objective-c-wkwebview-to-javascript-and-back/and the info at http://nshipster.com/wkwebkit/

我自己刚刚完成了这个，按照http://tetontech.wordpress.com/2014/07/17/objective-c-wkwebview-to-javascript-and-back/ 上的教程和http:// 上的信息nshipster.com/wkwebkit/

WKWebView has a built-in way of communicating between Javascript and Objective-C/Swift: WKScriptMessageHandler.

WKWebView 有一种内置的 Javascript 和 Objective-C/Swift 之间的通信方式：WKScriptMessageHandler.

First, include the WebKit headers and WKScriptMessageHandlerprotocol in your view controller's header:

首先，WKScriptMessageHandler在你的视图控制器的头文件中包含 WebKit 头文件和协议：

#import <UIKit/UIKit.h>
#import <WebKit/WebKit.h>
@interface ViewController : UIViewController <WKScriptMessageHandler>

@end

The when initialising your WKWebView, you need to configure it with a script message handler. Name it whatever you want, but to me it seems like naming it for your app makes sense.

初始化您的 时WKWebView，您需要使用脚本消息处理程序对其进行配置。随意命名它，但对我来说，为您的应用程序命名似乎很有意义。

    WKWebViewConfiguration *theConfiguration = 
          [[WKWebViewConfiguration alloc] init];
    [theConfiguration.userContentController 
          addScriptMessageHandler:self name:@"myApp"];

    _theWebView = [[WKWebView alloc] initWithFrame:self.view.frame 
                      configuration:theConfiguration];
    [_theWebView loadRequest:request];
    [self.view addSubview:_theWebView];

Now, implement userContentController:didReceiveScriptMessage:. This fires when your webview receives a message, so it does the work you were previously doing with webView:shouldStartLoadWithRequest:navigationType:.

现在，实施userContentController:didReceiveScriptMessage:. 这会在您的 webview 收到消息时触发，因此它会执行您之前使用webView:shouldStartLoadWithRequest:navigationType:.

- (void)userContentController:(WKUserContentController *)userContentController 
                        didReceiveScriptMessage:(WKScriptMessage *)message {
    NSDictionary *sentData = (NSDictionary *)message.body;
    NSString *messageString = sentData[@"message"];
    NSLog(@"Message received: %@", messageString);
}

You're now ready to receive messages from Javascript. The function call you need to add to your Javascript is this:

您现在已准备好接收来自 Javascript 的消息。您需要添加到 Javascript 的函数调用是这样的：

window.webkit.messageHandlers.myApp.postMessage({"message":"Hello there"});

回答by SeanR

I've been looking for a good explanation myself, but haven't found one. I've used the following in my app and everything seems to work (Edit:updated based on ccoroom's comment):

我自己一直在寻找一个很好的解释，但没有找到。我在我的应用程序中使用了以下内容，一切似乎都有效（编辑：根据ccoroom 的评论更新）：

UIWebViewDelegate     - webView:shouldStartLoadWithRequest:navigationType:
WKNavigationDelegate  - webView:decidePolicyForNavigationAction:decisionHandler:

Here's the other UIWebViewDelegatemethods:

这是其他UIWebViewDelegate方法：

UIWebViewDelegate     - webViewDidStartLoad:
WKNavigationDelegate  - webView:didCommitNavigation:

UIWebViewDelegate     - webViewDidFinishLoad:
WKNavigationDelegate  - webView:didFinishNavigation:

UIWebViewDelegate     - webView:didFailLoadWithError:
WKNavigationDelegate  - webView:didFailNavigation:withError:
                      - webView:didFailProvisionalNavigation:withError:

I'd love for someone to confirm this for me though.

不过，我希望有人为我确认这一点。

Edit:Actually, I've answered the question you had in the title (although I'm no longer confident that webView:didCommitNavigation:is called at the exact same point in the lifecycle), but re-reading your description it looks like what you actually need to know about is how to reimplement a Javascript/Objective-C bridge using WKWebView. So have a look at my other answer.

编辑：实际上，我已经回答了您在标题中提出的问题（尽管我不再确信它webView:didCommitNavigation:是在生命周期的完全相同点调用的），但是重新阅读您的描述，它看起来像您实际需要的了解如何使用 WKWebView 重新实现 Javascript/Objective-C 桥。所以看看我的另一个答案。

回答by robnasby

To answer the original question, the equivalent of webView:shouldStartLoadWithRequest:navigationType:in UIWebView is webView:decidePolicyForNavigationAction:decisionHandler:in WKWebView. These methods are called before each request is made (including the initial request) and provide the ability to allow/disallow it.

要回答原始问题，webView:shouldStartLoadWithRequest:navigationType:UIWebView 中的等效项是webView:decidePolicyForNavigationAction:decisionHandler:WKWebView。这些方法在发出每个请求（包括初始请求）之前被调用，并提供允许/禁止它的能力。

回答by Benzi Heler

Just use the following method , it's a part of WKNavigationDelegate

只需使用以下方法，它是 WKNavigationDelegate 的一部分

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {

    NSURLRequest *request = navigationAction.request;
    NSString *url = [[request URL]absoluteString];

    decisionHandler(WKNavigationActionPolicyAllow);
}

回答by u2603230

In Swiftyou can do something like this:

在Swift 中，您可以执行以下操作：

func webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void) {

    switch navigationAction.request.URLString {
    case "http://action.is.needed/some-action":
        self.someFunc()
        decisionHandler(.Cancel)
        break
    default:
        decisionHandler(.Allow)
        break
    }

}

And this is the link in web page:

这是网页中的链接：

<a href="http://action.is.needed/some-action">Hello world!</a>

回答by ingconti

for swift 4.2: (taking from Yifei He 何一非. )

for swift 4.2：（摘自何一非。）

 func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void) {

        let url = navigationAction.request.url
        let urlStr = url?.absoluteString
        switch urlStr {
        case BASE_URL:
            //self.someFunc()
            decisionHandler(.cancel)
            break
        default:
            decisionHandler(.allow)
            break
        }

    }

回答by ramzi shadid

You can add Observer for your WKWebView

您可以为 WKWebView 添加观察者

 static void* keyValueObservingContext = &keyValueObservingContext;

[webView addObserver:self forKeyPath:@"URL" options:0 context:keyValueObservingContext];


- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
 {

if ([keyPath isEqualToString:@"URL"]){
// do something
  }
}

Don't forget to remove it in viewWillDisappear

不要忘记在 viewWillDisappear 中删除它

-(void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
[webView removeObserver:self forKeyPath:@"URL"];
}