Runtime error, unable to use developer mode

Every time I'm connecting to MIT App Inventor on my phone, I always getting these error message

Error message #2
And if you wondering, it's showing white screen in the app

Show us:

  • Your Companion version on the phone
  • Your Downloaded Blocks Image
  • Your exported .aia file
  • The error counts in the Blocks Editor, red and yellow, for all screens.
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How to avoid runtime errors with the companion app

  1. After importing an extension, please restart the companion app.
  2. If you like to use an extension on a different screen, in Screen1 additionally drag the extension into the working area.

While starting the companion app, all necessary assets and also the imported extensions of your project will be copied to your device. So in case the no such class error shows up, the extension code to run the extension is not available on your device. Without that code the companion app is not able to execute methods from the extension.

In case restarting the companion app does not work for you after trying several times, then as it looks like the only way for you to test you app will be after building it using the apk file


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