Fragment Factory

Koin integrates with AndroidX FragmentFactory to enable constructor injection in Fragments.

info

Fragment Factory uses DSL only. Annotation and Compiler Plugin DSL support is not yet available.

Setup

Add Dependency

implementation "io.insert-koin:koin-android:$koin_version"

Configure Fragment Factory

In your Koin configuration, enable the fragment factory:

startKoin {
    androidContext(this@MainApplication)
    fragmentFactory()
    modules(appModule)
}

Declaring Fragments

Use the fragment DSL keyword with constructor injection:

class MyFragment(
    private val myService: MyService
) : Fragment()

val appModule = module {
    single { MyService() }
    fragment { MyFragment(get()) }
}

Using Fragments

Setup in Activity

Call setupKoinFragmentFactory() before super.onCreate():

class MyActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        // Must be called BEFORE super.onCreate()
        setupKoinFragmentFactory()

        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
}

Add Fragment

Use the reified extension function:

supportFragmentManager.beginTransaction()
    .replace<MyFragment>(R.id.container)
    .commit()

With arguments and tag:

supportFragmentManager.beginTransaction()
    .replace<MyFragment>(
        containerViewId = R.id.container,
        args = bundleOf("key" to "value"),
        tag = "my_fragment"
    )
    .commit()

Fragment Factory with Scopes

To use Activity-scoped dependencies in your Fragment:

val appModule = module {
    scope<MyActivity> {
        scoped { ActivityService() }
        fragment { MyFragment(get()) }
    }
}

Pass the scope to setupKoinFragmentFactory():

class MyActivity : AppCompatActivity(), AndroidScopeComponent {

    override val scope: Scope by activityScope()

    override fun onCreate(savedInstanceState: Bundle?) {
        // Pass scope to fragment factory
        setupKoinFragmentFactory(scope)

        super.onCreate(savedInstanceState)
    }
}

Quick Reference

Action	Code
Declare fragment	fragment { MyFragment(get()) }
Setup global factory	setupKoinFragmentFactory()
Setup with scope	setupKoinFragmentFactory(scope)
Add fragment	.replace<MyFragment>(R.id.container)

Next Steps

• AndroidX Fragment - Official Fragment documentation
• Scopes - Android scopes
• ViewModel - ViewModel injection