I returned to Android Development after a hiatus of three years and it did not come as a surprise to me that the lay of the land has changed significantly. Over the past few days I have been trying to wrap my head around the new ecosystem by lurking in the subreddits, slack channels and by general good old-fashioned googling. Here’s a run down of the five essential libraries or patterns that are in vogue.
Dagger 2 is a library for Dependency Injection. The concept of Dependency Injection took Java Enterprise world by storm in the last decade. It is the Star Wars of the Java Concepts in that it spawned many merchs, sequels, I mean libraries, consultancies. Essentially, you have a library which provides Dependencies to the objects of your application. Spring Framework and Guice have been the pioneers. Dagger is the new entrant and the USP is that it provides compile time guarantees that the dependencies are met. I remember using Spring Framework, wiring my dependencies only to find out the web server throw up a giant stack trace about a teeny-tiny dependency not wired. So, Dagger (it’s an Object Grapher, more specifically a Directed Acyclic Graph-er, or Dagger, gettit?) is a welcome entrant.
Using Dependency Injection has its advantages in that it makes for a testable code base. and the Architecture is decoupled. Having said that, I found that the learning curve was a bit steep.
Note: Dagger 1 or Dagger was developed by Square. Dagger 2 is a fork by Google and is actively maintained by folks at Google.
RxJava has taken the Java World by storm. Rx and its reactive extensions enable Functional Reactive Programming in the language of your choice. RxJava has received a lot of love from the Java community. Android is the natural place for implementing FRP. Many libraries use RxJava as well. Retrofit, the sweetest library to call REST APIs, uses RxJava in the backend. Retrolambda is a great companion library because it helps in writing lambda expressions in the subscribe and observe apis resulting in succinct and fluent code.
Butterknife uses dependency injection to inject widgets into your code so that your View code is not littered with findViewByIds. Doesn’t sound much but I have grown to love this library so much so that the first refactor that I do on an old source code is using Butterknife to inject the views. It is one of those libraries that you thought you didn’t need it until you used and now cannot let go. It is the fidget-spinner of Android Libraries.
Glide is an Android Library for loading images. It does what it says on the tin, only better than the alternatives like Picasso.
MVP stands for Model View Presenter Pattern. It is a pattern that most developers are gravitating towards now a days. As your Android Application grows adopting this pattern will help in structuring the application this way. The pattern takes a leaf from the MVC pattern and recommends separating the view layer from the model layer. In the beginning I thought this was a bit much and takes a lot of work but persevering helped because many developers are using this pattern to structure their apps.
Other sources for learning are downloading Google Android Architecture sample apps. You can also look at the trending repositores in Gitub for Java, a majority of them currently are Android Libraries or sample applications because, let’s face it, Android is where it’s at.