Question

在UIWebView中，我可以通过以下方式获取JSContext：

[webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"]

当WKWebView和应用程序到达此行代码时，同样的方式无效。

有没有办法在WKWebView中获取JSContext？

提前感谢。

Answer 1

您无法获取上下文，因为布局和javascript是在另一个进程上处理的。

相反，将脚本添加到webview配置中，并将视图控制器（或其他对象）设置为脚本消息处理程序。

现在，像这样发送来自JavaScript的消息：

window.webkit.messageHandlers.interOp.postMessage(message)

您的脚本消息处理程序将收到回调：

- (void)userContentController:(WKUserContentController *)userContentController 
                            didReceiveScriptMessage:(WKScriptMessage *)message{
    NSLog(@"%@", message.body);
}

Answer 2

像这样配置你的wkwebview并相应地添加处理程序并以类似模式从脚本发布消息

NSString *myScriptSource = @"alert('Hello, World!')";


WKUserScript *s = [[WKUserScript alloc] initWithSource:myScriptSource injectionTime:WKUserScriptInjectionTimeAtDocumentStart forMainFrameOnly:YES];
WKUserContentController *c = [[WKUserContentController alloc] init];
[c addUserScript:s];
// Add a script message handler for receiving  "buttonClicked" event notifications posted from the JS document using window.webkit.messageHandlers.buttonClicked.postMessage script message
[c addScriptMessageHandler:self name:@"buttonClicked"];

WKWebViewConfiguration *conf = [[WKWebViewConfiguration alloc] init];
conf.userContentController = c;

WKWebView *webview = [[WKWebView alloc] initWithFrame:self.view.bounds configuration:conf];
[self.view addSubview:webview];
webview.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
// Do any additional setup after loading the view, typically from a nib.
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://google.com"]];
[webview loadRequest:request];

实现脚本消息处理程序＆＃34; WKScriptMessageHandler＆＃34;方法名称

#pragma mark -WKScriptMessageHandler
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message          {
if ([message.name isEqualToString:@"buttonClicked"]) {
self.buttonClicked ++;
}

// JS objects are automatically mapped to ObjC objects
id messageBody = message.body;
if ([messageBody isKindOfClass:[NSDictionary class]]) {
NSString* idOfTappedButton = messageBody[@"ButtonId"];
[self updateColorOfButtonWithId:idOfTappedButton];
}
}

并发布消息格式js，如此

var button = document.getElementById("clickMeButton");
button.addEventListener("click", function() {
    var messgeToPost = {'ButtonId':'clickMeButton'};
    window.webkit.messageHandlers.buttonClicked.postMessage(messgeToPost);
},false);

Answer 3

XWebView是解决您问题的好方法。它可以在native和JS之间建立桥梁，并提供绑定样式的API。

如何从WKWebView获取JSContext

3 个答案: