Android Jetpack ViewModel, Dagger 2, Kotlin coroutines

DaggerViewModelFactory.kt

package example

import android.arch.lifecycle.ViewModel
import android.arch.lifecycle.ViewModelProvider
import dagger.Binds
import dagger.MapKey
import dagger.Module
import javax.inject.Inject
import javax.inject.Provider
import kotlin.reflect.KClass

@Suppress("UNCHECKED_CAST")
class DaggerViewModelFactory @Inject constructor(private val viewModelsMap: Map<Class<out ViewModel>, @JvmSuppressWildcards Provider<ViewModel>>) :
        ViewModelProvider.Factory {

    override fun <T : ViewModel> create(modelClass: Class<T>): T {
        val creator = viewModelsMap[modelClass] ?: viewModelsMap.asIterable().firstOrNull {
            modelClass.isAssignableFrom(it.key)
        }?.value ?: throw IllegalArgumentException("unknown model class $modelClass")
        return try {
            creator.get() as T
        } catch (e: Exception) {
            throw RuntimeException(e)
        }
    }
}

@Module
abstract class ViewModelFactoryModule {
    @Binds
    abstract fun bindViewModelFactory(viewModelFactory: DaggerViewModelFactory): ViewModelProvider.Factory
}

@Target(AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY_GETTER, AnnotationTarget.PROPERTY_SETTER)
@MapKey
annotation class ViewModelKey(val value: KClass<out ViewModel>)

FragmentWithViewModels.kt

package example

import android.arch.lifecycle.ViewModel
import android.arch.lifecycle.ViewModelProvider
import android.arch.lifecycle.ViewModelProviders
import javax.inject.Inject

abstract class FragmentWithViewModels : ScopedFragment() {

    @Inject
    lateinit var viewModelFactory: ViewModelProvider.Factory
}

inline fun <reified T : ViewModel> FragmentWithViewModels.getViewModel(): T {
    return ViewModelProviders.of(this, viewModelFactory).get(T::class.java)
}

ScopedFragment.kt

package example

import android.os.Bundle
import android.support.v4.app.Fragment
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlin.coroutines.CoroutineContext

abstract class ScopedFragment : Fragment(), CoroutineScope {

    protected lateinit var job: Job
    override val coroutineContext: CoroutineContext
        get() = job + Dispatchers.Main

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        job = Job()
    }

    override fun onDestroy() {
        super.onDestroy()
        job.cancel()
    }
}