Use APKPure App
Get How To Tutorials - Android old version APK for Android
Easy to understand & simple Android Tutorials
This app contains tutorials on Android and how to implement certain functionalities and features in you Android application.
Easy to understand, simple and short tutorials with example code and live demos.
It currently has limited tutorials but more will be added in future updates.
This assumes that you know some basics of Android and are not completely new to it.