Created
December 6, 2019 13:56
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Helper methods to retrieve an instance of ViewModel via Kodein.
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import androidx.lifecycle.ViewModel | |
import androidx.lifecycle.ViewModelProvider | |
import androidx.lifecycle.ViewModelStoreOwner | |
import org.kodein.di.* | |
import org.kodein.di.generic.bind | |
import org.kodein.di.generic.factory | |
import org.kodein.di.generic.instance | |
import org.kodein.di.generic.provider | |
class ViewModelFactory(private val injector: LazyKodein) : ViewModelProvider.Factory { | |
override fun <T : ViewModel> create(modelClass: Class<T>): T = | |
injector.direct.instance<ViewModel>(tag = modelClass.simpleName) as T | |
} | |
data class ViewModelParams( | |
val owner: ViewModelStoreOwner, | |
val params: DefinitionParameters | |
) | |
inline fun <C, reified T : Any, reified R : ViewModel> Kodein.BindBuilder.WithContext<C>.viewModel( | |
noinline creator: DKodeinAware.(DefinitionParameters) -> R | |
) = factory { viewModelParams: ViewModelParams -> | |
// Local kodein is used to hide | |
// actual ViewModel binding | |
val localLazyKodein = Kodein.lazy { | |
extend(this@factory.kodein) | |
bind<ViewModel>(R::class.java.simpleName) with provider { | |
creator(viewModelParams.params) | |
} | |
} | |
ViewModelProvider( | |
viewModelParams.owner, | |
ViewModelFactory(localLazyKodein) | |
).get(R::class.java) as T | |
} | |
/** | |
* Returns a kodein property with a ViewModel injected | |
* into it. | |
*/ | |
inline fun <T, reified Property : Any> T.viewModels(vararg params: Any?): KodeinProperty<Property> where | |
T : KodeinAware, | |
T : ViewModelStoreOwner = run { | |
val argument = ViewModelParams(this, DefinitionParameters(params)) | |
instance(arg = argument) | |
} | |
@Suppress("UNCHECKED_CAST") | |
class DefinitionParameters( | |
private vararg val values: Any? | |
) { | |
init { | |
if (values.size > 5) | |
error( | |
""" | |
Sorry, because of the limitations of Kotlin language, you can not | |
pass more that 5 arguments. Please use data types instead of multiple | |
arguments. | |
""".trimIndent() | |
) | |
} | |
private fun <T> elementAt(i: Int): T = | |
if (values.size > i) values[i] as T else error("Can't get parameter value #$i from $this") | |
operator fun <T> component1(): T = elementAt(0) | |
operator fun <T> component2(): T = elementAt(1) | |
operator fun <T> component3(): T = elementAt(2) | |
operator fun <T> component4(): T = elementAt(3) | |
operator fun <T> component5(): T = elementAt(4) | |
/** | |
* get element at given index | |
* return T | |
*/ | |
operator fun <T> get(i: Int) = values[i] as T | |
} |
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How to bind the view model: