WKWebView JavaScript将消息发送到Objective-C并返回值

如何使用WKWebView，JavaScript将消息发送到Objective-C并返回值

像这样：

NSString *token = [NSString stringWithFormat:@"localStorage.setItem(\"accessToken\",'%@');",@"74851c23358c"];

WKUserScript *wkUScript = [[WKUserScript alloc] initWithSource:sendToken injectionTime:WKUserScriptInjectionTimeAtDocumentStart forMainFrameOnly:NO];
WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];

[config.userContentController addScriptMessageHandler:[[WeakScriptMessageDelegate alloc] initWithDelegate:self] name:@"iOS"];

[config.userContentController addUserScript:wkUScript];

WKWebView *webview = [[WKWebView alloc] initWithFrame:CGRectMake(0, 0, SCREENWIDTH, SCREENHEIGHT) configuration:config];

让result=window.webkit.messageHandlers.name.postMessage（）

添加名为的脚本消息处理程序 使JavaScript函数window.webkit.messageHandlers.name.postMessage（messageBody）在使用用户内容控制器的所有web视图的所有帧中定义

---

我找到了另一种方法，通过将WKUserScriptInjectionTimeAtDocumentStart参数插入js到web的本地存储中。 像这样：

NSString *token = [NSString stringWithFormat:@"localStorage.setItem(\"accessToken\",'%@');",@"74851c23358c"];

WKUserScript *wkUScript = [[WKUserScript alloc] initWithSource:sendToken injectionTime:WKUserScriptInjectionTimeAtDocumentStart forMainFrameOnly:NO];
WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];

[config.userContentController addScriptMessageHandler:[[WeakScriptMessageDelegate alloc] initWithDelegate:self] name:@"iOS"];

[config.userContentController addUserScript:wkUScript];

WKWebView *webview = [[WKWebView alloc] initWithFrame:CGRectMake(0, 0, SCREENWIDTH, SCREENHEIGHT) configuration:config];

---

这不是我想要的结果。