If you won't to learn programming in java directly in your android smartphone, aide for android can be a good app, it is an editor, a compiler and they are many lessons as well.
It is like an advanced course of sololearn in java for android.
After learning all that lessons eclipse or android studio will be easy to use.
I'm having some problems to install Android Studio properly. The emulator doesn't show my programs. A course on installing that IDE would be great. The official Web-Page is just marketing. Meanwhile I'm reading 'Do Androids dream of electric sheep?' by Philip K. Dick (from PlayStore).