The training period of Android is generally 4 months, and the training period of different institutions may be different, but almost all of them are about 4 months.

Ordinary Android training is about 15 thousand, and high-end Android training is more than 20 thousand. The difference is that ordinary classes accept zero foundation, while high-end classes aim at foundation.

There will naturally be a gap in employment salary. Wages with low technical level are 6-8k, wages with medium technical level are around 10k, and wages with high technical level are generally around 15k+, and some even 20k+.

Introduction to software development self-study tutorial?

There are no tutorials. If you have a little basic knowledge, I suggest you watch some basic videos first (many training institutions put basic videos in their official website), and then find some books about this language to study together. If you don't understand, you can check it online. Then I kept learning. There are many knowledge points in programming languages, which are easy to forget. You should chew them bit by bit.