AppDelegate中的stringByEvaluatingJavaScript如何

Question

SOLVED

I used observer in ViewController

I have a iOS webview in Swift3 and need call Js function from AppDelegate. The reason why is because i'm using push notifications, and when the user click on notification i need to pass the information from swift3 to JS.

This is the head of my ZhWebViewController

class ZhWebViewController: UIViewController, UIWebViewDelegate { func passNotificationToWebView(userInfo: AnyObject){ let jsonData = try! JSONSerialization.data(withJSONObject: userInfo, options:
JSONSerialization.WritingOptions.prettyPrinted) let jsonString = NSString(data: jsonData, encoding:
String.Encoding.utf8.rawValue)! as String self.webView.stringByEvaluatingJavaScript(from: "triggerNotificationClick(\\ (jsonString))") } }

This is how i declare my UIWebView

@IBOutlet weak var webView: UIWebView!

This is how i call JS functions, this way works!!!

self.webView.stringByEvaluatingJavaScript(from: "someFunctionJS(\\(jsonString))")

This is head of my AppDelegate

@UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate { var window: UIWindow? }

This is where i receive notification and here i want to call JS function , i try call a function in ZHWebView and there try to send to JS, but i get fatal error.

@available(iOS 10, *) extension AppDelegate : UNUserNotificationCenterDelegate{ func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) { let userInfo = response.notification.request.content.userInfo ZhWebViewController().passNotificationToWebView(userInfo: userInfo as AnyObject) completionHandler() } }

Answer 1

Update:

It seems I totally misunderstood your question. The question is not how to evaluate some JavaScript but how to get from your app delegate to your view controller. These should help you:

• How to go directly to a specific View Controller if Notification has been opened
• What is correct way to notify view controller from AppDelegate?

Original answer:

It depends on whether you are using a UIWebView or a WKWebView . The main difference evaluating JavaScript code between UIWebView.stringByEvaluatingJavaScript() and WKWebView.evaluateJavaScript() is that the former call is synchronous and the latter is asynchronous.

Compare

let webView: UIWebView = ...
let result = webView.stringByEvaluatingJavaScript(from: "your javascript goes here")

with

let webView: WKWebView = ...
webView.evaluateJavaScript("your javascript goes here") { (result: Any?, error: Error?) in
    // handle completion
}

Please note the UIWebView API Reference states

In apps that run in iOS 8 and later, use the WKWeb​View class instead of using UIWeb​View.
[...]
Although this method [stringByEvaluatingJavaScript] is not deprecated, best practice is to use the evaluate​Java​Script(_:​completion​Handler:​) method of the WKWeb​View class instead.

Which is further emphasized by WKWebView's API Reference :

Important
Starting in iOS 8.0 and OS X 10.10, use WKWebView to add web content to your app. Do not use UIWebView or WebView.