“Default Activity Not Found” on Android Studio upgrade

Question

I upgraded IntelliJ Idea from 12.0.4 to 12.10.

Now all the modules in my Android project give the error:

Error: Default Activity Not Found

Answer 1

Since Android Studio 3.5 or 3.6 I started getting the Default Activity not found and I became tired of Invalidating Caches & Restart, rebuilding project etc.

It turned out, the way I handle multi-modules and manifests was erroneous. I had the default Activity's Manifest in library module only, but it should've been in both app modules.

Assuming librarymodule appmodule1 appmodule2

1. Remove HomeActivity from librarymodule Manifest whatsoever.
2. Add:

class AppModuleActivity1 : HomeActivity() to appmodule1
class AppModuleActivity2 : HomeActivity() to appmodule2

3. To appmodule1 Manifest inside application tag, I added:

4. Same about appmodule2 but change 2 for 1 in naming.