ReactNativeWebView is Not Recognised

Question

I’m using react-native-webview and attempting to post a message from JavaScript to RN.

I’m using the window.ReactNativeWebView.postMessage() method but cannot get beyond some issue with ReactNativeWebView not being recognised, with the following error:

Cannot read property 'postMessage' of undefined

I’m using the following:

• "react": "16.8.3",
• "react-native": "0.59.8",
• "react-native-webview": "^5.12.0",

This looks so straight forward so I don’t know where I’m going wrong.

Answer 1

Declare and use the reference value.

 onLoadEnd() {
   this.webview.postMessage("yourmessage");
  }

 <WebView
          ref={webview => (this.webview = webview)}
          onLoadEnd={() => this.onLoadEnd()}
          ...
        />

Your webview_uri should have a message-receiver just like React-native's.

webpage example

document.addEventListener("message", function(event) {
    console.log("Received post message", event);

    logMessage(event.data);
}, false);