#12 provide option for runtime to listen for lifecycle changes and respond

Author: semanticer

elmdroid/build.gradle

@@ -25,8 +25,10 @@ dependencies {
     implementation deps.kotlin.stdlib
 
     // arch
+    implementation deps.lifecycle.runtime
     implementation deps.lifecycle.viewmodel
     implementation deps.lifecycle.livedata
+    implementation deps.lifecycle.java8
 
     // rx
     implementation deps.rx_java2

elmdroid/src/main/java/cz/inventi/elmdroid/ElmArchitecture.kt

@@ -1,17 +1,26 @@
 package cz.inventi.elmdroid
 
+import android.arch.lifecycle.DefaultLifecycleObserver
+import android.arch.lifecycle.LifecycleOwner
 import android.arch.lifecycle.LiveData
 import io.reactivex.Observable
 import io.reactivex.Single
 
 /** UI 'loop' implementation that 'runs" given [Component]. */
-interface ComponentRuntime<STATE : State, in MSG : Msg> {
+interface ComponentRuntime<STATE : State, in MSG : Msg> : DefaultLifecycleObserver {
     /** Provides always up to date [State]. */
     fun state(): LiveData<STATE>
     /** Dispatch [Msg] to handle. */
     fun dispatch(msg: MSG)
     /** Stops the inner loop, no more state updates. */
     fun clear()
+    /** Runtime will be able to call [clear] by itself based on the [lifecycleOwner] */
+    fun bindTo(lifecycleOwner: LifecycleOwner) {
+        lifecycleOwner.lifecycle.addObserver(this)
+    }
+    override fun onDestroy(owner: LifecycleOwner) {
+        clear()
+    }
 }
 
 /** Key class specifying all mayor pars of your elm architecture. */

elmdroid/src/main/java/cz/inventi/elmdroid/ElmViewModel.kt

@@ -6,7 +6,7 @@ import android.arch.lifecycle.ViewModel
 
 open class ElmViewModel<STATE : State, in MSG : Msg, CMD : Cmd> (component: Component<STATE, MSG, CMD>, logLevel: LogLevel = LogLevel.NONE) :
         ViewModel(),
-        ComponentRuntime<STATE, MSG> by RxRuntime<STATE, MSG, CMD>(component, logLevel) {
+        ComponentRuntime<STATE, MSG> by RuntimeFactory.create(component, logLevel = logLevel) {
 
     override fun onCleared() {
         super.onCleared()
@@ -18,7 +18,7 @@ abstract class ElmBaseViewModel<STATE : State, MSG : Msg, CMD : Cmd>(logLevel: L
         Component<STATE, MSG, CMD>,
         ComponentRuntime<STATE, MSG> {
 
-    private val runtime = RxRuntime(this, logLevel)
+    private val runtime = RuntimeFactory.create(this, logLevel = logLevel)
 
     override fun state(): LiveData<STATE> = runtime.state()
 
@@ -31,7 +31,7 @@ abstract class ElmSimpleBaseViewModel<STATE : State, MSG : Msg>(logLevel: LogLev
         SimpleComponent<STATE, MSG>,
         ComponentRuntime<STATE, MSG> {
 
-    private val runtime = RxRuntime(this, logLevel)
+    private val runtime = RuntimeFactory.create(this, logLevel = logLevel)
 
     override fun state(): LiveData<STATE> = runtime.state()
 

elmdroid/src/main/java/cz/inventi/elmdroid/RuntimeFactory.kt

@@ -1,9 +1,15 @@
 package cz.inventi.elmdroid
 
+import android.arch.lifecycle.LifecycleOwner
+
 
 object RuntimeFactory {
     var defaultLogLevel = LogLevel.NONE
-    fun <STATE : State, MSG : Msg, CMD : Cmd> create(component: Component<STATE, MSG, CMD>, logLevel: LogLevel = defaultLogLevel): ComponentRuntime<STATE, MSG> {
-        return RxRuntime(component, logLevel)
+    fun <STATE : State, MSG : Msg, CMD : Cmd> create(component: Component<STATE, MSG, CMD>, lifecycleOwner: LifecycleOwner? = null, logLevel: LogLevel = defaultLogLevel): ComponentRuntime<STATE, MSG> {
+        val rxRuntime = RxRuntime(component, logLevel)
+        if (lifecycleOwner != null) {
+            rxRuntime.bindTo(lifecycleOwner)
+        }
+        return rxRuntime
     }
 }

elmdroid/src/test/java/cz/inventi/elmdroid/ComponentRuntimeTest.kt

@@ -1,6 +1,9 @@
 package cz.inventi.elmdroid
 
 import android.arch.core.executor.testing.InstantTaskExecutorRule
+import android.arch.lifecycle.Lifecycle
+import android.arch.lifecycle.LifecycleOwner
+import android.arch.lifecycle.LifecycleRegistry
 import android.arch.lifecycle.Observer
 import cz.inventi.elmdroid.utils.RxImmediateSchedulerRule
 import org.junit.Before
@@ -11,6 +14,7 @@ import org.mockito.Mock
 import org.mockito.Mockito.`when`
 import org.mockito.Mockito.verify
 import org.mockito.MockitoAnnotations
+import org.mockito.Spy
 
 
 class ComponentRuntimeTest {
@@ -20,11 +24,11 @@ class ComponentRuntimeTest {
     @get:Rule
     val instantExecutorRule = InstantTaskExecutorRule()
 
-    private lateinit var runtime: ComponentRuntime<TestState, TestMsg>
+    @Spy lateinit var runtime: ComponentRuntime<TestState, TestMsg>
     @Mock lateinit var observer: Observer<TestState>
     @Mock lateinit var component: Component<TestState, TestMsg, TestCmd>
 
-
+    private lateinit var lifecycleOwner: TestLifecycleOwner
 
     companion object {
         @JvmField
@@ -35,17 +39,23 @@ class ComponentRuntimeTest {
     @Before
     fun setUp() {
         MockitoAnnotations.initMocks(this)
-
+        `when`(component.initState()).thenReturn(TestState(3, "init"))
+        lifecycleOwner = TestLifecycleOwner()
+        runtime = RuntimeFactory.create(component)
     }
 
     @Test
     fun initState() {
-        `when`(component.initState()).thenReturn(TestState(3, "init"))
-        runtime = RuntimeFactory.create(component)
         runtime.state().observeForever(observer)
         verify(observer).onChanged(TestState(3, "init"))
     }
 
+    @Test
+    fun autoClear() {
+        lifecycleOwner.markState(Lifecycle.State.CREATED)
+        lifecycleOwner.markState(Lifecycle.State.DESTROYED)
+        verify(runtime).clear()
+    }
 }
 
 data class TestState(val number: Int, val text: String): State
@@ -57,3 +67,11 @@ data class NumberMsg(val number: Int) : TestMsg()
 sealed class TestCmd: Cmd
 data class NumberCmd(val num: Int): TestCmd()
 
+class TestLifecycleOwner : LifecycleOwner {
+    private val lifecycleRegistry: LifecycleRegistry = LifecycleRegistry(this)
+    override fun getLifecycle(): Lifecycle = lifecycleRegistry
+    fun markState(state: Lifecycle.State) {
+        lifecycleRegistry.markState(state)
+    }
+}
+

elmdroid/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker

@@ -0,0 +1 @@
+mock-maker-inline

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip

sample/src/main/java/com/example/elmdroid/counter/CounterActivity.kt

@@ -17,7 +17,7 @@ class CounterActivity : AppCompatActivity() {
         setContentView(R.layout.activity_counter)
         supportActionBar?.title = getString(R.string.basic_counter)
 
-        runtime = RuntimeFactory.create(CounterComponent())
+        runtime = RuntimeFactory.create(CounterComponent(), this)
 
         runtime.state().observe(this, Observer {
             it?.let { counter.text = "${it.counter}" }
@@ -26,9 +26,4 @@ class CounterActivity : AppCompatActivity() {
         increment.setOnClickListener { runtime.dispatch(Increment) }
         decrement.setOnClickListener { runtime.dispatch(Decrement) }
     }
-
-    override fun onDestroy() {
-        super.onDestroy()
-        runtime.clear()
-    }
 }

sample/src/main/java/com/example/elmdroid/login/presentation/LoginActivity.kt

@@ -19,7 +19,7 @@ class LoginActivity : AppCompatActivity(), LoginView  {
 
         supportActionBar?.title = getString(R.string.complex_login)
 
-        runtime = RuntimeFactory.create(LoginComponent())
+        runtime = RuntimeFactory.create(LoginComponent(), this)
 
         // observe state
         runtime.state().observe(this, LoginRenderer(this))
@@ -30,11 +30,6 @@ class LoginActivity : AppCompatActivity(), LoginView  {
         loginButton().setOnClickListener { runtime.dispatch(LoginClicked) }
     }
 
-    override fun onDestroy() {
-        super.onDestroy()
-        runtime.clear()
-    }
-
     override fun email(): EditText = email
     override fun password(): EditText = password
     override fun loginButton(): Button = loginButton

sample/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker

@@ -0,0 +1 @@
+mock-maker-inline