The importance of patterns

When a software developer has to develop a feature or a component with a certain functionality, it can usually be done in different ways; it can be done with different code or with a different structure. It is very likely that the same problem has been solved by other developers so many times that the solution is abstracted from particular implementations and transformed into a pattern. Rather than invent the wheel again, it is preferable to know and implement these patterns.

When developing on Android, we use patterns every day even if we aren't aware of it. Most of the time, we use implementations of the patterns built in Android. For instance, when we want to perform a click on a button and set OnClickListener—in other words, wait for the onClick() method to be called—we use an observer pattern implementation. If we create a popup, AlertDialog, we use AlertDialog.Builder, which uses the Builder pattern. There are many examples, but what we...