[FEAT] Create base viewmodel, action and state abstractions

peterkrauz · Sep 23, 2020 · a22875c · a22875c
1 parent 6383b87
commit a22875c
Show file tree

Hide file tree

Showing 2 changed files with 19 additions and 7 deletions.
diff --git a/common/src/main/java/com/peterkrauz/grimoire/common/BaseViewModel.kt b/common/src/main/java/com/peterkrauz/grimoire/common/BaseViewModel.kt
@@ -3,14 +3,26 @@ package com.peterkrauz.grimoire.common
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
+import kotlin.properties.Delegates
+import kotlin.reflect.KProperty
 
-class BaseViewModel<S : BaseViewState, A : BaseViewAction>(state: S) : ViewModel() {
+abstract class BaseViewModel<out S : BaseViewState, A : BaseViewAction>(state: S) : ViewModel() {
+
+    private var state by Delegates.observable(state, ::onStateChanged)
 
     private val _stateLiveData = MutableLiveData<S>()
-    val stateLiveData: LiveData<S>
+    val stateLiveData: LiveData<out S>
         get() = _stateLiveData
 
-    fun putState(state: S) {
-        _stateLiveData.postValue(state)
+    fun performAction(action: A) {
+        state = reduceState(action)
+    }
+
+    abstract fun loadData()
+
+    protected abstract fun reduceState(action: A): S
+
+    private fun onStateChanged(property: KProperty<*>, oldState: S, newState: S) {
+        _stateLiveData.postValue(newState)
     }
 }
diff --git a/common/src/main/java/com/peterkrauz/grimoire/common/BaseViewState.kt b/common/src/main/java/com/peterkrauz/grimoire/common/BaseViewState.kt
@@ -1,5 +1,5 @@
 package com.peterkrauz.grimoire.common
 
-interface BaseViewState
-
-object Loading : BaseViewState
+interface BaseViewState {
+    object Loading : BaseViewState
+}