Dagger 2 Tutorial Part 1 WHAT IS DEPENDENCY INJECTION Android Studio Tutorial

What is dagger module? Modules are a way of telling Dagger how to provide dependencies from the dependency graph. These are typically high level dependencies that you aren't already contributing to the dependency graph through the @Inject constructor annotation we discussed in our previous article.How does a dagger work? Dagger generates code similar to what you would have written manually. Internally, Dagger creates a graph of objects that it can reference to find the way to provide an instance of a class. For every class in the graph, Dagger generates a factory-type class that it uses internally to get instances of that type.What is dagger 2 used for? Dagger 2 walks through the dependency graph and generates code that is both easy to understand and trace, while also saving you from writing a large amount of boilerplate code you would normally need to write by hand to obtain references and pass them to other objects as dependencies.Why should we use dagger? Why dagger-android? The idea behind dagger-android is to reduce the boilerplate needed to inject objects. To be even more specific, the idea is to reduce that boilerplate code in Fragments, Activities or any other Android framework classes that are instantiated by the OS.What is the use of dagger in Android? In Android, you usually create a Dagger graph that lives in your application class because you want an instance of the graph to be in memory as long as the app is running. In this way, the graph is attached to the app lifecycle. In some cases, you might also want to have the application context available in the graph.