hilt.md

Notes

• https://developer.android.com/codelabs/android-hilt#6

  • In Kotlin, modules that only contain @Provides functions can be object classes. This way, providers get optimized and almost in-lined in generated code.

• https://developer.android.com/training/dependency-injection/hilt-android

  • If you annotate an Android class with @AndroidEntryPoint, then you also must annotate Android classes that depend on it. For example, if you annotate a fragment, then you must also annotate any activities where you use that fragment.

• https://developer.android.com/codelabs/android-hilt#8

  • Since the different implementations of LoggerDataSource are scoped to different containers, we cannot use the same module: LoggerInMemoryDataSource is scoped to the Activity container and LoggerLocalDataSource to the Application container.

  • We need to define a qualifier per implementation since each qualifier will be used to identify a binding.

Flowchart for determining how to inject a dependency using Hilt

Select the first of the following options that applies to your use case.

1. If you want to inject your own class, constructor-inject it.
2. If you want to inject an interface, you have a class that implements the interface, and you can instantiate the class without any additional code, use @Binds.
3. Otherwise, use @Provides.