How to make a program for yourself and download it to your smartphone?

Question

Java

Hello dear,
please advise on the development of applications for Android.
I need to make a help application for myself and download it to my smartphone.
How can I do it?
I will write a program in java, how to make the interface further?
And how can I install it in my smartphone?
Can I download the program directly?
Or for this you need to do everything through the market?

Answer 1

Briefly, here is https://developer.android.com/training/index.html
to write in Java immediately for android, there are disappearingly few programs for android without UI.
You can install directly via adb.
market is not required.

Answer 2

Today I tried to dance a little with Xamarin and AndroidStudio with a tambourine - nah, so many troubles, I already ate with setting up the emulator for VisualStydio, additional installations, search for Hyper-V, without disabling which the emulator does not work normally .... I already had programming experience in JS and PHP - it's better if I make a program online - I'll upload it to my site, make access through a password and use it from any device, it will be much easier))