JavaScript to Swift communication

Question

john217 OP

Created Dec ’17

Replies 1

Boosts 0

Views 5.8k

Participants 4

Hey guys,

Programming environemnt :

swift version : 4.0

xcode version : 9.2

My objective :

1- Open a web application in ios and

2 - Communicate with its elements using JavaScript - invoke a method in my native app

what I have done so far :

I can load my application using webkit view.

challenges :

I found few old instructions for invoking native code from web applications JS functions which sadly won't work in newer versions of swift. due to swift upgrade.

function/methods like : NSBundle that are no longer available.

Main Question :

how can I invoke a method in native app from JavaScript

Thank you

Boost

Answer 1

DTS Engineer OP

Apple

Dec ’17

how can I invoke a method in native app from JavaScript

That depends on what type of web view you’re using. The recommended web view for this sort of thing is

WKWebView

. In that view you can invoke native methods from JavaScript via the

WKScriptMessage

mechanism:

When you create the web view, you have to pass in a
```
WKWebViewConfiguration
```
. Add yourself as a script message handler for the message in question:
```
webViewConfiguration.userContentController.add(self, name: "myMessageName")
```
.

In JavaScript, send a message with code like this:

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

.

Back in native, this will call the script message handler method that you registered:

func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
    assert(message.name == "myMessageName")
    … handle the message …
}

.

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Apple Developer Relations, Developer Technical Support, Core OS/Hardware

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