Merge pull request #8 from etiennelenhart/delegate-patch

Delegate patch

eiffel/src/main/java/com/etiennelenhart/eiffel/viewmodel/delegate/ProvidedFactoryViewModel.kt

@@ -36,12 +36,12 @@ class ProvidedFactoryViewModel<out T : ViewModel>(private val viewModelClass: Cl
  *
  * May be used in a [FragmentActivity] like this:
  * ```
- * val viewModel by providedFactoryViewModel<SampleViewModel>(sampleFactory)
+ * val viewModel by providedViewModel<SampleViewModel>(sampleFactory)
  * ```
  *
  * @param[T] Type of the provided view model.
  * @param[factory] Block to lazily get the factory to instantiate the view model.
  */
-inline fun <reified T : ViewModel> FragmentActivity.providedFactoryViewModel(noinline factory: () -> ViewModelProvider.Factory): ProvidedFactoryViewModel<T> {
+inline fun <reified T : ViewModel> FragmentActivity.providedViewModel(noinline factory: () -> ViewModelProvider.Factory): ProvidedFactoryViewModel<T> {
     return ProvidedFactoryViewModel(T::class.java, factory)
 }

eiffel/src/main/java/com/etiennelenhart/eiffel/viewmodel/delegate/ProvidedFragmentFactoryViewModel.kt

@@ -42,6 +42,6 @@ class ProvidedFragmentFactoryViewModel<out T : ViewModel>(private val viewModelC
  * @param[T] Type of the provided view model.
  * @param[factory] Block to lazily get the factory to instantiate the view model.
  */
-inline fun <reified T : ViewModel> Fragment.providedFactoryViewModel(noinline factory: () -> ViewModelProvider.Factory): ProvidedFragmentFactoryViewModel<T> {
+inline fun <reified T : ViewModel> Fragment.providedViewModel(noinline factory: () -> ViewModelProvider.Factory): ProvidedFragmentFactoryViewModel<T> {
     return ProvidedFragmentFactoryViewModel(T::class.java, factory)
 }

eiffel/src/main/java/com/etiennelenhart/eiffel/viewmodel/delegate/SharedFactoryVieModel.kt

@@ -0,0 +1,47 @@
+package com.etiennelenhart.eiffel.viewmodel.delegate
+
+import android.arch.lifecycle.ViewModel
+import android.arch.lifecycle.ViewModelProvider
+import android.arch.lifecycle.ViewModelProviders
+import android.support.v4.app.Fragment
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+/**
+ * Property delegate to lazily provide a shared [ViewModel] instantiated by a [ViewModelProvider.Factory]
+ * from the [ViewModelProvider] of this [Fragment]s Activity.
+ *
+ * May be used in a [Fragment] like this:
+ * ```
+ * val viewModel by SharedFactoryViewModel(SampleViewModel::class.java, sampleFactory)
+ * ```
+ *
+ * @param[T] Type of the provided view model.
+ * @param[viewModelClass] Java class of the provided view model.
+ * @param[factory] Block to lazily get the factory to instantiate the view model.
+ */
+class SharedFactoryViewModel<out T : ViewModel>(private val viewModelClass: Class<T>,
+                                                private val factory: () -> ViewModelProvider.Factory) : ReadOnlyProperty<Fragment, T> {
+
+    private var value: T? = null
+
+    override fun getValue(thisRef: Fragment, property: KProperty<*>): T {
+        if (value == null) value = ViewModelProviders.of(thisRef.activity!!).get(viewModelClass)
+        return value!!
+    }
+}
+
+/**
+ * Convenience inline function to use [SharedFactoryViewModel] delegate with type parameter instead of Java class.
+ *
+ * May be used in a [Fragment] like this:
+ * ```
+ * val viewModel by sharedViewModel<SampleViewModel>(sampleFactory)
+ * ```
+ *
+ * @param[T] Type of the provided view model.
+ * @param[factory] Block to lazily get the factory to instantiate the view model.
+ */
+inline fun <reified T : ViewModel> Fragment.sharedViewModel(noinline factory: () -> ViewModelProvider.Factory): SharedFactoryViewModel<T> {
+    return SharedFactoryViewModel(T::class.java, factory)
+}