Another aspect to this is that Android is Linux, but it is not GNU / Linux. This is true both in the literal sense of not using GNU coreutils or glibc, and also in the broader sense.
What I mean by the “broader” sense:
no X or Wayland
GTK or Qt support is something an application has to bring with them.
filesystem is substantially reorganized
users and system permissions setup substantially differently
To the application programmer Android / Linux looks like a completely different ball game.
Another aspect to this is that Android is Linux, but it is not GNU / Linux. This is true both in the literal sense of not using GNU coreutils or glibc, and also in the broader sense.
What I mean by the “broader” sense:
To the application programmer Android / Linux looks like a completely different ball game.