diousk

public abstract class FragmentInjectActivity extends AppCompatActivity
        implements HasAndroidInjector {

    @Inject DispatchingAndroidInjector<Object> androidInjector;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        AndroidInjection.inject(this);
        beforeOnCreate(); // <-- expose here for child to do things before onCreate
        super.onCreate(savedInstanceState);

diousk

class MainActivity : DaggerAppCompatActivity() {

    @Inject lateinit var fragmentFactory: FragmentFactory

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

diousk

@Module
abstract class DummyBuilder {
    @ContributesAndroidInjector(modules = [DummyModule::class])
    abstract fun bindDummygFragment(): DummyFragment

    // put binding of fragment at this layer(not DummyModule) for parent to inject
    @Binds
    @IntoMap
    @FragmentKey(DummyFragment::class)
    abstract fun bindDummyFragment(fragment: DummyFragment): Fragment

diousk

@Module
abstract class MainBuilder {
    @ContributesAndroidInjector(modules = [
        ViewModelBuilder::class,
        FragmentBuilder::class, // <- for injection of fragment factory
        MainModule::class,
        DummyBuilder::class // <- our fragment
    ])
    abstract fun bindMainActivity(): MainActivity
}

diousk

@Module
abstract class FragmentBuilder {
    @Binds
    abstract fun bindFragmentFactory(
        factory: DaggerFragmentFactory
    ): FragmentFactory
}

diousk

@Target(
    AnnotationTarget.FUNCTION,
    AnnotationTarget.PROPERTY_GETTER,
    AnnotationTarget.PROPERTY_SETTER
)
@Retention(AnnotationRetention.RUNTIME)
@MapKey
annotation class FragmentKey(val value: KClass<out Fragment>)

diousk

class DaggerFragmentFactory @Inject constructor(
    private val providers: @JvmSuppressWildcards Map<Class<out Fragment>, Provider<Fragment>>
) : FragmentFactory() {

    override fun instantiate(classLoader: ClassLoader, className: String): Fragment {
        val fragmentClass = loadFragmentClass(classLoader, className)
        val provider = providers[fragmentClass]
        return provider?.get() ?: super.instantiate(classLoader, className)
    }
}

diousk

class DummyFragment @Inject constructor(
    private val repo: AppRepo
) : DaggerFragment() {
    @Inject
    lateinit var vmFactory: ViewModelProvider.Factory
    private val viewModel by viewModels<DummyViewModel> { vmFactory }
    // ...
}

diousk

class MainActivity: FragmentInjectActivity() {
    @Inject lateinit var fragmentFactory: FragmentFactory

    override fun onCreate(savedInstanceState: Bundle?) {
        supportFragmentManager.fragmentFactory = fragmentFactory
        super.onCreate(savedInstanceState)
        // launch fragment and add to fragmen container view
        supportFragmentManager.beginTransaction()
            .add<DummyFragment>(R.id.fragmentContainer)
            .commit()

diousk

package com.diousk.serializationsample

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import androidx.lifecycle.lifecycleScope
import com.diousk.serializationsample.model.MockData
import com.diousk.serializationsample.model.mockDataList
import com.diousk.serializationsample.model.mockJsonString
import com.diousk.serializationsample.parser.GsonParser