Add sharedActivityViewModel

Author: Adrián García

CHANGELOG.md

@@ -5,8 +5,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Add `sharedActivityViewModel` to Kodein extensions to support shared Activity view models.
 ### Fixed
 - Fix `ConcurrentModificationException`s in store subscriptions' iteration by adding safe iteration over them.
+### Changed
 - Rename `toggleAbility` to `toggleEnabled` as the name was confusing.
 
 ## [1.1.2] - 2020-02-07

mini-kodein-android/src/main/java/mini/kodein/android/KodeinAndroidUtils.kt

@@ -55,7 +55,7 @@ class KodeinViewModelFactory(private val injector: DKodein,
  * Injects a [ViewModel] into a [FragmentActivity] that implements [KodeinAware].
  */
 @MainThread
-inline fun <reified VM : ViewModel, T> T.viewModel(): Lazy<VM> where T : KodeinAware, T : FragmentActivity {
+inline fun <reified VM : ViewModel, A> A.viewModel(): Lazy<VM> where A : KodeinAware, A : FragmentActivity {
     return lazy {
         ViewModelProviders.of(this, direct.instance()).get(VM::class.java)
     }
@@ -65,7 +65,7 @@ inline fun <reified VM : ViewModel, T> T.viewModel(): Lazy<VM> where T : KodeinA
  * Injects a [ViewModel] into a [Fragment] that implements [KodeinAware].
  */
 @MainThread
-inline fun <reified VM : ViewModel, T> T.viewModel(): Lazy<VM> where T : KodeinAware, T : Fragment {
+inline fun <reified VM : ViewModel, F> F.viewModel(): Lazy<VM> where F : KodeinAware, F : Fragment {
     return lazy {
         ViewModelProviders.of(this, direct.instance()).get(VM::class.java)
     }
@@ -97,6 +97,31 @@ inline fun <reified T, reified VM : TypedViewModel<T>, F> F.viewModel(params: T)
     }
 }
 
+/**
+ * Injects a [ViewModel] with an [Activity] context that implements [KodeinAware], in order to share it between
+ * different fragments hosted by that same [Activity].
+ */
+@MainThread
+inline fun <reified VM : ViewModel, F> F.sharedActivityViewModel(): Lazy<VM> where F : KodeinAware, F : Fragment {
+    return lazy {
+        ViewModelProviders.of(this.requireActivity(), direct.instance()).get(VM::class.java)
+    }
+}
+
+/**
+ * Injects a [ViewModel] with an [Activity] context that implements [KodeinAware], in order to share it between
+ * different fragments hosted by that same [Activity].
+ *
+ * Requires previous [ViewModelProvider.Factory] injection for the [ViewModel] via [bindViewModelFactory]
+ * to work and a [TypedViewModel] to be used.
+ */
+@MainThread
+inline fun <reified T, reified VM : TypedViewModel<T>, F> F.sharedActivityViewModel(params: T): Lazy<VM> where F : KodeinAware, F : Fragment {
+    return lazy {
+        ViewModelProviders.of(this.requireActivity(), direct.instance(VM::class.java, params)).get(VM::class.java)
+    }
+}
+
 /**
  * Generic [ViewModel] that adds support for adding a single [params] object to ease parameter
  * injection.