Mastering Dependency Injection in Android with Dagger Hilt (and a Contrast Taste of Koin)
In modern Android development, dependency injection (DI) is a key technique to build modular, testable, and maintainable apps. In DI, a class does not create its own dependencies; instead, dependencies are provided (injected) from the outside. In other words, the class receives the objects it needs rather than constructing them itself. This “inversion of control” makes your code loosely coupled and easier to refactor. For example, a UserRepository can be injected into a ViewModel rather than the ViewModel building the repository, so you can swap implementations or mock it during tests. In Android, doing all this by hand is tedious. You would have to manually construct every object and manage its lifecycle.
