Facing issues with adding sharedPreferences and the sharedPrefrencesEditor to Koin module

Question

I recently got to know about Koin. I was trying to migrate my current project from Dagger to Koin. In doing so, I faced an issue with injecting sharedPreferences and sharedPreferences editor in the activities.

Following is the code I used in Dagger to inject sharedPreferences and sharedPreferences editor ->

    @Provides
    @AppScope
    fun getSharedPreferences(context: Context): SharedPreferences =
            context.getSharedPreferences("default", Context.MODE_PRIVATE)

    @SuppressLint("CommitPrefEdits")
    @Provides
    @AppScope
    fun getSharedPrefrencesEditor(context: Context): SharedPreferences.Editor =
            getSharedPreferences(context).edit()

I tried to convert the above mentioned code to Koin like this ->

val appModule = module {

    val ctx by lazy{ androidApplication() }

    single {
        ctx.getSharedPreferences("default", Context.MODE_PRIVATE)
    }

    single {
        getSharedPreferences(ctx).edit()
    }
}

I also tried to implement it this way ->

val appModule = module {

        single {
            androidApplication().getSharedPreferences("default", Context.MODE_PRIVATE)
        }

        single {
            getSharedPreferences(androidApplication()).edit()
        }
    }

Now I inject the dependencies in my activity like this ->

val sharedPreferences: SharedPreferences by inject()

val sharedPreferencesEditor: SharedPreferences.Editor by inject()

But as soon as I launch my app and try to use them, I am not able to read or write anything to the preferences.

I am a bit confused as to what is wrong with the code. Kindly help me figure this out.

Answer 1

I figured out a way to handle this. Hope this helps someone looking for the same issue.

Here is the solution to the problem:

The koin module definition will be like this ->

 val appModule = module {

    single{
        getSharedPrefs(androidApplication())
    }

    single<SharedPreferences.Editor> {
        getSharedPrefs(androidApplication()).edit()
    }
 }

fun getSharedPrefs(androidApplication: Application): SharedPreferences{
    return  androidApplication.getSharedPreferences("default",  android.content.Context.MODE_PRIVATE)
}

Just to be clear that the above code is in the file modules.kt

Now you can easily inject the created instances like ->

private val sharedPreferences: SharedPreferences by inject()

private val sharedPreferencesEditor: SharedPreferences.Editor by inject()

Make sure the above instances are val instead of var otherwise the inject() method will not work as this is lazy injection.