Android programming, I'm finishing soaking up the headfirst book and I have a big question?

Question

IT education

It’s hard to remember which pattern does what, and it’s even harder to create an application in which these patterns fit in as native ones, of course, such patterns as a decorator, an observer, a singleton stood up as native ones, but with regards to others - everything was mixed up in a heap, and this is my question , in fact, stood up:

Patterns worth knowing everything like our father? Or all the patterns presented in this book only give examples for specific implementations, but in fact, they are used in everyday life much less, and if so, could you tell me which patterns exactly I should know and wake me up in the dead of night, with eyes closed, I will have to implement these patterns without error?

I also have a misunderstanding, I often hear on the Internet, they say, having completed wonderful courses for a devops or layout designer in 3-5 months, people with their hands are torn off to work, while I, without taking courses, still only dream of a job ...

Answer 1

what patterns exactly should I know and, having woken me up late at night, with my eyes closed, will I have to realize these patterns without error?

Generally none. It is important not to be able to implement without error. It is important to understand what pattern, what problem it solves, in what cases it is used, and by the name of the pattern alone, this should pop up in the head. So that when you communicate with other developers, you can explain your solution using a pattern dictionary.

Or all the patterns presented in this book only give examples for specific implementations, but in fact, they are used in everyday life much less.

In fact, they are used much more.

Answer 2

From the question, it looks like you are finishing "Design Patterns" by Freeman and Robson. And, apparently, you did not read it carefully, otherwise the answer to your question was written there several times.
PS Android what does your question have to do with it?

Answer 3

I also have a misunderstanding, I often hear on the Internet, they say, having completed wonderful courses for a devops or layout designer in 3-5 months, people with hands are torn off to work

They can tear off their hands, but they are unlikely to take them to work.