debug-webviews.mo

Owner: Louis Zawadzki

Prerequisites

• A React Native application with a WebView

• Safari if you want to debug on an iOS device

Steps iOS (~2min)

• Run your app on your iOS simulator

• Open Safari

• Enable the "Develop" menu:

  • Pull down the "Safari" menu and choose "Preferences"

  • Click on the "Advanced" tab

  • Check the box next to "Show Develop menu in menu bar"

• Pull down the "Develop" menu

• Click on "Simulator" that should be right below your computer

• Select your WebView in the menu

Steps Android (~3min)

• In your android/app/src/main/java/com/applilabchatbot/MainApplication.java add import android.webkit.WebView; in the imports and the following line in your onCreate method:

@Override
public void onCreate() {
  super.onCreate();
  SoLoader.init(this, /* native exopackage */ false);
+ WebView.setWebContentsDebuggingEnabled(true);
}

• Launch your app

• Open Chrome

• Go to chrome://inspect
• Select your WebView under your device name

Common WebViews pitfalls

• To inject Javascript you have to set your WebView's javaScriptEnabled prop to true

• On Android, you can't use arrow functions in the injected javascript

• window.postMessage might not be available straight away in your injected Javascript, to make sure it's the case you can wrap your injected code by a setTimeout like this:

setTimeout(function() {
  /* your injected js goes here */
}, 0)