Getting error when trying to use cardview

[Souvik Bera]

Hello, I'm trying to use cardview in my extension. But the problem is that when I use the extension it shows this error

failed resolution of: landroid/support/v7/cardview/r$attr;

This error shows in every distribution of AppInventor and AppInventor itself exept Kodular. What is thereason behind it and how can I solve it ?

I'm using Cardview 28.0.0

[Souvik Bera]

NoClassDefFound error. Any solution ??