Remove the The project can be successfully built now. It goes to the Login Activity again.

It crashed after registering! This fails @Module class Module { @Provides fun adder (): (Int, Int) -> Int = {x, y -> x + y} } class SomeClass { @Inject lateinit var adder: (Int, Int) -> Int fun init { component.inject(this) println (" ${adder(1, 2)} = 3 ") } } error: kotlin.jvm.functions.Function2

Both main and registration flow are getting The problem is that Dagger always provides a new instance of a type (in our case Sometimes, you might want to provide the same instance of a dependency in a Component for multiple reasons: Use Scopes to have a unique instance of a type in a Component. Dependency Injection 用フレームワークライブラリのことです. In order to ask Dagger to inject the dependency you would have to somehow provide a MainApp instance: init { mainApp.appComponent.inject(this) } which doesn't make much sense since you'd like to inject it (as a Context) in the first place. Instead of using a We have to swap the There, create a new file called Because of how Dagger doesn't know how to create instances of Now we provide an instance of Let's create a new Kotlin file in the following path: We need to specify all the modules in this test Component too.

In this codelab you'll learn the importance of Dependency Injection (DI) to create a solid and extensible application that scales to large projects. Join G. Blake Meike for an in-depth discussion in this video, Method and field injection, part of Android Dependency Injection with Dagger 2 and Kotlin. We're now ready to use Dagger in the app.Dagger is implemented using Java's annotations model.

As you can see, we called the class We've told Dagger that when a to create instances of The application graph needs to know about In this way, If we try to build again we get an error very similar to what we got before! In this course, Blake Meike teaches Android developers to use Dagger 2 with Kotlin—the newly embraced Android programming language. For example, if we wanted different A For example, if we had We can add the different implementations with In the example, we defined two qualifiers: You can achieve the same functionality as qualifiers with the There's one more part of the codelab app for you to experiment with - adding a splash screen.

It simplifies application logic by moving the code to Dagger 2 configuration. The generated class is called What does our The instance of Now, As In Android, you usually create a Dagger graph that lives in your Application class because you want the graph to be in memory as long as the app is running.

Qualifiers are useful when you want to add different implementations of the same type to the Dagger graph. Dagger 2, the latest version, is particularly highly regarded for its speed and compile-time safety.

Since we want If you run Can we scope We want to create a Component that lives as long as the user is logged in. This is what is also called "For Open the Now, classes annotated with Now, the same instance of Run The solution of the codelab at this point can be found in the In case you're curious, this is what the application graph looks like now:Notice that Let's keep refactoring our app to Dagger.

NOTE: Refer to Android Dagger 2 Injection For Fragment (Kotlin). This time, what Dagger doesn't find is: How can we tell Dagger how to provide The way to pass it in is with a Component Factory and using the We're declaring an interface annotated with Use Your project should now build with no errors.. Dagger has generated the application graph successfully and you're ready to use it.