How to create an Extension

There may be two reasons:

  1. The path has spaces
  2. You ran the wrong command; run ant extensions instead.

Actually I am trying to follow this step

Step 5: Testing if it works

Go to your appinventor-sources folder and open the appinventor folder
Right click in the folder and select “Git Bash Here”
Type “ant” and click on enter
If says: “BUILD SUCCESSFUL”, then you can go to Step 6
If says: “BUILD FAILED”, then you did something wrong or missed a step

Ok, follow this updated guide

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You could just use Makeroid IDE and forget about installing or downloading anything :wink:


Thank You So much this is very easy and stress free method to build an extension for newcomers.


How to add .aar file to Library ?
Will we be added in the same way as we add .jar ?

.aar files aren’t currently supported in extensions unfortunately.
See Evan’s answer here:


You can try to extract the JAR inside the AAR, but it isn’t guaranteed that it will work


Off topic. Create a new one for your request.

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How to add .java file to Library or how to convert Bundle of .java file as .jar ?
Will we be added in the same way as we add .jar ?

Is there any guide or tutorial that how we can develop extension in New ExtensionIDE platform?

Not yet, sorry :sweat_smile:

Any one please help me

For java help use Google.

You cant add libs to the MakeroidIDE

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will there be a way to upload libs in the future ?

I think on the paid plan you can add them

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Most of Android library not working only JAR file need AAR file like - Java.class with Value.xml file.


I’m gonna try making an extension with no skills and some of googles help and see where I get my 1,00 errors worth of time :joy:, I’m unzipping appinventor-sources now.

Edit: I have successfully built my extension however added no blocks or properties, I wanted to test to see if it worked and now I’m on my way.


These may help you get on your way:

Taifun has shared some great source code here:

And here:

Scroll to the bottom of the page to see source code.

Also check out:!topic/app-inventor-open-source-dev


The new link is not working. It’s showing 404 Not Found.

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