Programming Android with Kotlin

Chapter 4. Concurrency in Android

This chapter does not focus specifically on Kotlin. Instead, it will introduce some of the issues that surround concurrent programming and that the rest of the book addresses. It will also introduce a few tools, already available to Android developers, for managing concurrent tasks.

Concurrent programming has a reputation as kind of a dark art: something that is done by self-proclaimed wizards and that novices touch at their peril. Certainly, writing correct concurrent programs can be quite challenging. This is particularly true because errors in concurrent programs don’t always show up right away. It is nearly impossible to test for concurrency bugs and they can be extremely difficult to reproduce, even when they are known to exist.

A developer concerned about the hazards of concurrent programming would do well to remember these three things:

• Nearly everything you do, every day, except programming, is concurrent. You get along quite nicely in a concurrent environment. It is programming, where things happen in order, that is odd.

• If you are trying to understand the issues that concurrent programming presents, you are on the right path. Even an incomplete understanding of concurrency is better than copying sample code and crossing your fingers.

• Concurrent programming is just how Android works. Anything other than the most trivial Android application will require concurrent execution. Might as well get on with it and figure out what it’s all ...