I want to achieve a TabBar with Tabs with the following layout:

I found multiple examples where the whole TabBar background is changed but I could not find out how to customize the background for unselected tabs individually, since the grey background is bound to the TabView and not the individual Tab.

In the example image provided, the grey background progress depends on a bool property isAvailable of the data that is used to render the respective Tab/ TabView.
The green progress bar indicates which tabs are done.
The grey progress bar indicates which tabs are available but not done yet.
The last tab is not available yet, therefore it is not included in the grey progress.

Question:
How can I achieve a Tab layout/ design like in the image provided? And if not with the Tab/ TabView widget, is there another way?

Thanks for your help!