Logcat (I tinified all images I am using, now this is my new Logcat): 03-30 15:53:13.841 31645-31645/de.mm.uchron E/AndroidRuntime: FATAL EXCEPTION: main So I guess the problem depends on the Android version? I've emulated an Nexus 5 with API 23, when I try it with an emulated Pixel with API 24 the emulator also crashes. But if I try to run the app on my Samsung Galaxy S7 Edge (Android 7.0) the app crashes instantly. I've worked on an app with a normal login screen and on the emulator everything works fine.
I started using Android Studio a few weeks ago.