For Android I started off using MIT’s app inventor:
This was fun and I had some success with a few projects, however as a touch typist I am always more comfortable using the keyboard. As I was already using the amazing Processing IDE for desktop Java apps, Processing for Android was the next step:
Of course there is no substitute for the real thing, which is what I am using most often now, Android Studio. Processing for Android provides a handy tool for exporting sketches as they are called, so the transistion is pretty seamless. Android Studio is a huge IDE with bells, whistles, mags and stickers attached. Learning how to use this beast is going to take a long time, especially with Google pulling out the rug (ie changing everything with each new release) every couple of months.