Dagger 2, Providing Application Context In Module

Im pretty new in Android development and newer in DI. I am using Kotlin on a personal project where I am experimenting with Dagger 2. I managed to set it up for a util class, but w

Solution 1:

This is how It is done. Using @BindsInstance in your component will inject application to all of your modules.In your case just to AppModule

@Singleton@Component(modules = arrayOf(AppModule::class))
interfaceAppComponent{
    @Component.Builder
    interfaceBuilder() {
        funbuild(): AppComponent

        @BindsInstancefunapplication(application: Application): Builder
    }
}

** Delete code to "Provides application" function in your APP module and make sure you pass application context to create sharedPreferences.

@Module
class AppModule {


@Provides@Singleton
fun provideSharedPrefManager(context: Application): SharedPreferencesManager = 
    SharedPreferencesManager(context)
}

and now in your onCreate of applicationClass

DaggerAppComponent.builder().application(this).build()

Optional: if you want to inject something into your applicationClass then do the following

 DaggerAppComponent.builder().application(this).build().inject(this)

Solution 2:

You can't use class PineApplication @Inject constructor(): Application() to create PineApplication. It's a framework class and has to be created by the Android Framework.

Doing so Dagger will create PineApplication, but applicationContext will return null as it has never been initialized (by the system).

Don't use constructor injection for framework classes and don't create the yourself. Use @Bindsintance to add the object to the component with its builder, or use a module to provide it.

Solution 3:

For provide application context, you can create class, like ComponentsManager with:

publicclassComponentsManager {

    private Context context;
    private AppComponent appComponent;

    publicComponentsManager(Context context) {
        this.context = context.getApplicationContext();
    }

    public AppComponent getAppComponent(){
        if (appComponent == null){
            appComponent = DaggerAppComponent.builder()
                    .appModule(new AppModule(context))
                    .build();
        }
        return appComponent;
    }
}

And in your application class init this ComponentsManager like this:

publicclassYourAppextendsApplication {

    privatestaticComponentsManager componentsManager;

    @OverridepublicvoidonCreate() {
        super.onCreate();
        initComponentsManager();
        initAppComponent();
    }

    publicstaticComponentsManagergetComponentsManager(){
        return componentsManager;
    }

    privatevoidinitComponentsManager(){
        componentsManager = newComponentsManager(this);
    }

    privatevoidinitAppComponent(){
        componentsManager.getAppComponent();
    }
}

Solution 4:

You can try modifying your App module like this.

@ModuleclassApplicationModule(privateval application: Application) {

    @Provides@SingletonfunprovideContext(): Context {
        return application.applicationContext
    }

    @Provides@SingletonfunprovideSharedPreferences(context: Context): SharedPreferences {
        return context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE)
    }
}

Then you can build the dagger component like this from your Application class.

val appComponent = DaggerAppComponent.builder()
                .applicationModule(ApplicationModule(this))
                .build()

Inject values in presenter like this.

application.appComponent.inject(this)