Inject database in a ContentProvider with dagger

Question

I want to inject a singleton SqliteOpenHelper in a ContentProvider. However, it seems that the ContentProvider instance is being built bef

Answer 1

based on @Mick answer and @LeEnot article I posted an article on Medium using new Dagger 2 features.

https://medium.com/@pedro.henrique.okawa/content-providers-dependency-injection-dagger-2-4ee3e49777b

But basically I put the Dagger-Android dependency:

// In my case I used 2.16 version
implementation 'com.google.dagger:dagger-android:[DaggerVersion]'

Implemented my custom Application class with HasContentProviderInjector interface and changed to inject my dependencies on attachBaseContext:

class App : Application(), HasActivityInjector, HasContentProviderInjector {

    @Inject
    lateinit var androidInjector: DispatchingAndroidInjector

    @Inject
    lateinit var contentProviderInjector: DispatchingAndroidInjector

    override fun activityInjector() = androidInjector

    override fun contentProviderInjector() = contentProviderInjector

    override fun attachBaseContext(base: Context?) {
        super.attachBaseContext(base)
        setupDependencyInjection()
    }

    /**
     * Injects the app component
     */
    private fun setupDependencyInjection() {
        DaggerAppComponent.builder().application(this).build().inject(this)
    }

}

And injected my databaseHelper instance on my ContentProvider class:

class VoIPAppProvider: ContentProvider() {

    @Inject
    lateinit var databaseHelper: DatabaseHelper

    override fun onCreate(): Boolean {
        AndroidInjection.inject(this)
        return true
    }

    override fun insert(uri: Uri?, contentValues: ContentValues?): Uri? {
        ...
        return uri
    }

    override fun query(uri: Uri?, projection: Array?, selection: String?, selectionArgs: Array?, sortOrder: String?): Cursor {
        ...
        return cursor
    }

    override fun getType(uri: Uri?): String {
        ...
        return type
    }
    override fun update(uri: Uri?, contentValues: ContentValues?, selection: String?, selectionArgs: Array?): Int {
        ...
        return rowsUpdated
    }

    override fun delete(uri: Uri?, selection: String?, selectionArgs: Array?): Int {
        ...
        return rowsDeleted
    }
}

PS: I decided to not use DaggerContentProvider class because most of us may already have a base class for some Android components.

I hope it help you and thanks again to @Mick and @LeEnot