The app I am developing has many activities organized into seven java packages. Originally I wrote all the coding and stuff for each group of activities in a java package as
Make sure that the import statement at the top of the Activity references the correct R file. Each project has its own R file, so if you copy an Activity from one project to another it will still be trying to reference the R file from the old project.
You do not need any explicit inclusion of different packages in the manifest. To include activities from two different packages, say:
com.example.package1.Activity1
com.example.package2.Activity2
you can do the following: