I accidentally created a new project within a package like "companyname.applicationname". So I forgot the top level domain. It should be "de.company.application".
I managed to modify my project. I changed the package in my manifest, and also all paths and file locations which needed to be changed for the project to no longer give me errors.
So in Android Studio everything looks fine. But if I install the app on my phone, the package is still "company.application".
Have I missed any occurence of "company.application" in my app which need to be changed?