One way Android programming has changed over the years is that there are now many solid 3rd party code libraries for cases where you used to have to ‘roll your own’ code. This makes development much faster than it used to be. There’s a great new web page/list called the Android Arsenal that lists libraries.
I have found there’s still a learning curve in that the libraries themselves often have limitations or peculiarities. In particular, I have found that some don’t work well with Proguard and many need extending (understanding and changing the source code) to work in a ways that are particular to specific projects. Also, they tend to work outside any non exception-based runtime logging strategies you might have in place making it harder to diagnose problems ‘in the field’. They can also add unnecessary complexity/bloat when you just need a small part of the offered functionality. Finally, some might use, for example particular http libraries or background processing, mechanisms you might be avoiding in your own code. Nevertheless, the gains often outweigh the disadvantages and I encourage every Android developer to periodically review what’s available.
While on the subject of Android coding, also take a look at AndroidXRef if you haven’t done so already. It allows you to easily search the Android OS source code. It’s great for finding code examples.