from one dagger2 module how to access the SharedPr

问题:

Having the SharedPreferences provided from one dagger2 module, in another dagger2 module would like to use it,
how to do it?

the code below seems not working.

/** the component */

@Singleton
@Component(modules = arrayOf(DataManagerModule::class, 
                             AnotherModule::class))
interface DataManagerComponent {
    fun getDataManager() : DataManager
    fun getSharedPreferences() : SharedPreferences
}

/** the module 1 */

@Module
class DataManagerModule(@ApplicationContext private val appContext: Context) {

    @Singleton
    @Provides
    @ApplicationContext
    fun provideApplicationContext(): Context = appContext

    @Singleton
    @Provides
    fun provideSharedPreferences(): SharedPreferences {
        return appContext.getSharedPreferences(appContext.packageName, 
        Context.MODE_PRIVATE)
    }
}

/** the module 2 */

@Module
class AnotherModule(private val config1: String?, private val config2: Int?) {

    @Provides
    @Singleton
    internal fun provideClass2(context: Context): Class2 {

        if (config2 == null) {

            // how to get the preferences???
            // getSharedPreferences().edit().getInt(Constants.Settings, -1)

        }

        return class2(config1, config2, context)
    }
}

回答1:

since all these artifacts share the same scope, and the component is built using both modules, you should be able to simply add SharedPreferences as a parameter to provideClass2() in order to use it in the construction of Class2, like so:

@Provides
@Singleton
internal fun provideClass2(context: Context, prefs: SharedPreferences): Class2 {
    ...
}

回答2:

Since you have already defined how to retrieve SharedPreferences from DataManagerModule class you can simply change

internal fun provideClass2(context: Context): Class2 {
       ...
}

to

internal fun provideClass2(sharedPreferences: SharedPreferences): Class2 {
       ...
}

Have another class extend the Application class and declare it to the AndroidManifest like so:

class App: Application() {

    lateinit var dataManagerComponent: DataManagerComponent

    override fun onCreate() {
        super.onCreate()

        dataManagerComponent = DaggerDataManagerComponent.builder()
                .dataManagerModule(DataManagerModule(this))
                .anotherModule(AnotherModule("config1", 123))
                .build()
    }
}

Modify your component to include an inject function

@Singleton
@Component(modules = arrayOf(DataManagerModule::class,
        AnotherModule::class))
interface DataManagerComponent {
    fun getDataManager() : DataManager
    fun getSharedPreferences() : SharedPreferences
    // The activity/fragment you will need the values
    fun inject(target: MainActivity)
}

Then inject it to the activity

class MainActivity : AppCompatActivity() {

    @Inject lateinit var class2: Class2

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        (application as App).dataManagerComponent.inject(this)


        Log.i("CLASS2", class2.toString())
    }
}