Kotlin匕首改造现场注入

Question

When trying to inject field variables using dagger I'm getting null. Here are the files. Some are in Java and some in Kotlin

App.java

   public class App extends DaggerApplication{


    @Override
    protected AndroidInjector<? extends DaggerApplication> applicationInjector() {
        return DaggerAppComponent.builder().application(this).build();
    }
}

AppComponent.kt

@Singleton
@Component(modules = arrayOf(
        NetworkModule::class,
        ApplicationModule::class,
        AndroidSupportInjectionModule::class
        ))
interface AppComponent : AndroidInjector<TBApplication> {


    @Component.Builder
    interface Builder {

        @BindsInstance
        fun application(application: Application): AppComponent.Builder

        fun build(): AppComponent
    }
}

NetworkModule.kt

@Module
class NetworkModule {

    @Provides
    @Singleton
    fun provideOkHttpClient(): OkHttpClient {
        val builder = OkHttpClient.Builder();
        if (BuildConfig.DEBUG) {
            val interceptor = HttpLoggingInterceptor()
            interceptor.setLevel(HttpLoggingInterceptor.Level.BODY)
            builder.addInterceptor(interceptor).build()
        }
        return builder.build()
    }

    @Singleton
    @Provides
    fun provideRetrofit(client: OkHttpClient): Retrofit {
        val retrofit = Retrofit.Builder()
                .baseUrl(BaseApi.SITE_ENDPOINT)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .client(client)
                .build();
        return retrofit
    }


}

// Repository where injection should be done

    class Repository {

        private var examsService: BlogExamsService

        @Inject
        var retrofit: Retrofit? = null

        init {
            // retrofit is null here
            examsService = retrofit?.create(BlogExamsService::class.java)!!
        }
   }

Answer 1

Field injection won't work as you do not run inject() method.

To make it work with your approach you should call in you Repository class:

App.self.getComponent().inject(this)

Where:

self is static instance of your application

getComponent() public getter for ApplicationComponent

Though I would not recommend it in your case, it is a misuse of DI framework.

You should create RepositoryModule and @Provide instance of Repository the same as you have done with NetworkModule .

Answer 2

Change your Repository to:

class Repository {

    private var examsService: BlogExamsService

    @Inject
    constructor(retrofit: Retrofit) {
        examsService = retrofit.create(BlogExamsService::class.java)!!
    }
}