Migrate from RxJava to Coroutines (#24)

* migration to coroutines

* updated all tests

* convert list loading to regular coroutines

* removed RxJava dependency

* update documentation

build.gradle

@@ -7,16 +7,17 @@ buildscript {
         min_sdk = 14
         target_sdk = 28
 
-        kotlin_version = '1.3.70'
+        kotlin_version = '1.3.72'
+        coroutines_version = '1.3.7'
         robolectric_version = '4.2'
-        mockito_kotlin_version = '1.5.0'
+        mockito_kotlin_version = '2.1.0'
         test_core_version = '1.2.0'
         test_ext_version = '1.1.1'
         test_espresso_version = '3.2.0'
 
-        rxjava_version = '2.2.17'
-        rxandroid_version = '2.1.1'
         arch_lifecycle_version = '2.2.0'
+        arch_lifecycle_runtime_version = '2.3.0-alpha03'
+        arch_lifecycle_viewmodel_version = '2.3.0-alpha03'
         autodispose_version = '1.1.0'
         appcompat_version = '1.1.0'
         recyclerview_version = '1.1.0'
@@ -31,7 +32,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.6.1'
+        classpath 'com.android.tools.build:gradle:3.6.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath 'com.github.dcendents:android-maven-gradle-plugin:2.1'
         classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.8.0'

helium-core/README.md

@@ -31,8 +31,8 @@ Helium requires [java 8 support](https://developer.android.com/studio/write/java
 
 #### Notes on the implementation
 
- - Uses [RxJava](https://github.com/ReactiveX/RxJava) to handle communication between Logic and UI blocks.
- - Uses [AutoDispose](https://github.com/uber/AutoDispose) to automatically dispose subscriptions, no need to worry about cleaning up or detaching anything.
+ - Uses [Flow](https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/-flow/index.html) and [Coroutines](https://github.com/Kotlin/kotlinx.coroutines) to handle communication between Logic and UI blocks
+ - Uses [LifecycleScope](https://developer.android.com/topic/libraries/architecture/coroutines#lifecyclescope) and [ViewModelScope](https://developer.android.com/topic/libraries/architecture/coroutines#viewmodelscope) to automatically release resources, no need to worry about cleaning up or detaching anything
  - Uses `ViewModel` from the [Android Architecture Components](https://developer.android.com/topic/libraries/architecture/viewmodel.html) to retain logic blocks and their states across configuration changes
 
 ## A typical, real world example
@@ -78,7 +78,7 @@ You can also call your own constructor if you have dynamic data to pass to your
 
 ```kotlin
 val id = intent.extras.getLong(DATA_ID)
-val logic = getRetainedLogicBlock<MyLogic>() { MyLogic(id) }
+val logic = getRetainedLogicBlock<MyLogic> { MyLogic(id) }
 ```
 
 
@@ -93,14 +93,17 @@ class MyLogic(private val repository: MyRepository) : LogicBlock<MyState, MyEven
 
     @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
     private fun loadData() {
-        repository
-            .getData()
-            .doOnSubscribe { pushState(MyState.Loading) }
-            .async()
-            .subscribe(
-                { data -> pushState(MyState.DataReady(data)) },
-                { error -> pushState(MyState.Error(error)) }
-            )
+        launchInBlock { // launches a coroutine scoped to this LogicBlock
+            try {
+                pushState(MyState.Loading)
+                val data = withContext(Dispatchers.IO) {
+                    repository.getData()
+                }
+                pushState(MyState.DataReady(data))
+            } catch(error: Exception) {
+                pushState(MyState.Error(error))
+            }
+        }
     }
 
     override fun onUiEvent(event : MyEvent) {

helium-core/build.gradle

@@ -37,10 +37,12 @@ android {
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
 
-    api "io.reactivex.rxjava2:rxjava:$rxjava_version"
-    api "io.reactivex.rxjava2:rxandroid:$rxandroid_version"
+    api "org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutines_version"
+    api "org.jetbrains.kotlinx:kotlinx-coroutines-android:$coroutines_version"
+
+    api "androidx.lifecycle:lifecycle-viewmodel-ktx:$arch_lifecycle_viewmodel_version"
+    api "androidx.lifecycle:lifecycle-runtime-ktx:$arch_lifecycle_runtime_version"
     api "androidx.lifecycle:lifecycle-extensions:$arch_lifecycle_version"
-    api "com.uber.autodispose:autodispose-android-archcomponents-ktx:$autodispose_version"
 }
 
 apply from: '../maven-push.gradle'

helium-core/src/main/AndroidManifest.xml

@@ -1,2 +1 @@
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-          package="com.joaquimverges.helium.core"/>
+<manifest package="com.joaquimverges.helium.core" />

helium-core/src/main/java/com/joaquimverges/helium/core/AppBlock.kt

@@ -3,9 +3,12 @@ package com.joaquimverges.helium.core
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.coroutineScope
 import com.joaquimverges.helium.core.event.BlockEvent
 import com.joaquimverges.helium.core.state.BlockState
-import com.joaquimverges.helium.core.util.autoDispose
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 
 /**
  * Class responsible for assembling LogicBlocks and UiBlocks together.
@@ -31,9 +34,9 @@ class AppBlock<S : BlockState, E : BlockEvent>(
      * Once this is called, LogicBlock will receive events from the UIBlock, and UIBlock will receive state updates from the LogicBlock.
      * This also enables the LogicBlock to receive lifecycle events, by annotating functions with @OnLifecycleEvent.
      */
-    fun assemble(lifecycle: Lifecycle) {
-        logic.observeState().autoDispose(lifecycle).subscribe { ui.render(it) }
-        ui.observer().autoDispose(lifecycle).subscribe { logic.processEvent(it) }
+    fun assemble(lifecycle: Lifecycle, coroutineScope: CoroutineScope = lifecycle.coroutineScope) {
+        logic.observeState().onEach { ui.render(it) }.launchIn(coroutineScope)
+        ui.observer().onEach { logic.processEvent(it) }.launchIn(coroutineScope)
         lifecycle.addObserver(logic)
 
         childBlocks.forEach {

helium-core/src/main/java/com/joaquimverges/helium/core/LogicBlock.kt

@@ -3,13 +3,13 @@ package com.joaquimverges.helium.core
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LifecycleObserver
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
 import com.joaquimverges.helium.core.event.BlockEvent
 import com.joaquimverges.helium.core.state.BlockState
-import io.reactivex.Observable
-import io.reactivex.disposables.CompositeDisposable
-import io.reactivex.disposables.Disposable
-import io.reactivex.subjects.BehaviorSubject
-import io.reactivex.subjects.PublishSubject
+import kotlinx.coroutines.channels.BroadcastChannel
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.launch
 
 /**
  * A LogicBlock holds and publishes BlockState changes to a UiBlock for rendering.
@@ -24,9 +24,8 @@ import io.reactivex.subjects.PublishSubject
  */
 abstract class LogicBlock<S : BlockState, E : BlockEvent> : ViewModel(), LifecycleObserver {
 
-    private val disposables: CompositeDisposable = CompositeDisposable()
-    private val state: BehaviorSubject<S> = BehaviorSubject.create()
-    private val eventDispatcher: PublishSubject<E> = PublishSubject.create()
+    private val state: MutableStateFlow<S?> = MutableStateFlow(null)
+    private val eventDispatcher: BroadcastChannel<E> = BroadcastChannel(Channel.BUFFERED)
 
     /**
      * Implement this method to react to any BlockEvent emissions from the attached UiBlock.
@@ -39,35 +38,34 @@ abstract class LogicBlock<S : BlockState, E : BlockEvent> : ViewModel(), Lifecyc
      * Must have compatible [BlockEvent] for both blocks.
      */
     fun propagateEventsTo(otherBlock: LogicBlock<*, E>) {
-        eventDispatcher.subscribe { otherBlock.processEvent(it) }.autoDispose()
+        eventDispatcher.asFlow().onEach { otherBlock.processEvent(it) }.launchInBlock()
     }
 
     /**
      * Observe state changes from this LogicBlock
      */
-    fun observeState(): Observable<S> = state
+    fun observeState(): Flow<S> = state.filterNotNull()
 
     /**
      * Observe events received by this LogicBlock, useful for propagating events to parent LogicBlocks
      */
-    fun observeEvents(): Observable<E> = eventDispatcher
+    fun observeEvents(): Flow<E> = eventDispatcher.asFlow()
 
     /**
      * Pushes a new state, which will trigger any active subscribers
      */
-    fun pushState(state: S) = this.state.onNext(state)
-
-    /**
-     * Will automatically dispose this subscription when the block gets cleared
-     */
-    fun Disposable.autoDispose() = disposables.add(this)
-
-    override fun onCleared() = disposables.clear()
+    fun pushState(state: S) {
+        this.state.value = state
+    }
 
     // internal functions
 
     internal fun processEvent(event: E) {
         onUiEvent(event)
-        eventDispatcher.onNext(event)
+        eventDispatcher.offer(event)
     }
+
+    fun <T> Flow<T>.launchInBlock() = launchIn(viewModelScope)
+
+    inline fun launchInBlock(crossinline codeBlock: suspend () -> Unit) = viewModelScope.launch { codeBlock() }
 }

helium-core/src/main/java/com/joaquimverges/helium/core/UiBlock.kt

@@ -8,8 +8,10 @@ import androidx.annotation.IdRes
 import androidx.annotation.LayoutRes
 import com.joaquimverges.helium.core.event.BlockEvent
 import com.joaquimverges.helium.core.state.BlockState
-import io.reactivex.Observable
-import io.reactivex.subjects.PublishSubject
+import kotlinx.coroutines.channels.BroadcastChannel
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.asFlow
 
 /**
  * Base class for UiBlocks.
@@ -23,9 +25,9 @@ import io.reactivex.subjects.PublishSubject
  * @see com.joaquimverges.helium.core.event.BlockEvent
  * @see com.joaquimverges.helium.core.LogicBlock
  */
-abstract class UiBlock<in S : BlockState, E : BlockEvent>(
+abstract class UiBlock<in S : BlockState, E : BlockEvent> constructor(
     val view: View,
-    private val eventsObservable: PublishSubject<E> = PublishSubject.create(),
+    private val eventFlow : BroadcastChannel<E> = BroadcastChannel(Channel.BUFFERED),
     protected val context: Context = view.context
 ) {
 
@@ -58,10 +60,10 @@ abstract class UiBlock<in S : BlockState, E : BlockEvent>(
     /**
      * Observe the events pushed from this UiBlock
      */
-    fun observer(): Observable<E> = eventsObservable
+    open fun observer(): Flow<E> = eventFlow.asFlow()
 
     /**
      * Pushes a new BlockEvent, which will trigger active subscribers LogicBlocks
      */
-    fun pushEvent(event: E) = eventsObservable.onNext(event)
+    fun pushEvent(event: E) = eventFlow.offer(event)
 }

helium-core/src/main/java/com/joaquimverges/helium/core/retained/RetainedBlocks.kt

@@ -1,8 +1,8 @@
 package com.joaquimverges.helium.core.retained
 
-import androidx.lifecycle.ViewModel
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentActivity
+import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 
 /**

helium-navigation/src/main/AndroidManifest.xml

@@ -1,2 +1 @@
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-          package="com.joaquimverges.helium.navigation"/>
+<manifest package="com.joaquimverges.helium.navigation" />

helium-navigation/src/main/java/com/joaquimverges/helium/navigation/drawer/NavDrawerUi.kt

@@ -1,9 +1,10 @@
 package com.joaquimverges.helium.navigation.drawer
 
-import androidx.drawerlayout.widget.DrawerLayout
 import android.view.Gravity
 import android.view.LayoutInflater
+import android.view.View
 import android.view.ViewGroup
+import androidx.drawerlayout.widget.DrawerLayout
 import com.joaquimverges.helium.core.UiBlock
 import com.joaquimverges.helium.navigation.R
 
@@ -29,6 +30,22 @@ class NavDrawerUi(
         (drawerContainer.layoutParams as DrawerLayout.LayoutParams).gravity = gravity
         mainContainer.addView(mainContentUi.view)
         drawerContainer.addView(drawerUi.view)
+        drawerLayout.addDrawerListener(object : DrawerLayout.DrawerListener {
+            override fun onDrawerStateChanged(newState: Int) {
+            }
+
+            override fun onDrawerSlide(drawerView: View, slideOffset: Float) {
+            }
+
+            override fun onDrawerClosed(drawerView: View) {
+                pushEvent(NavDrawerEvent.DrawerClosed)
+            }
+
+            override fun onDrawerOpened(drawerView: View) {
+                pushEvent(NavDrawerEvent.DrawerOpened)
+            }
+
+        })
     }
 
     override fun render(state: NavDrawerState) {

helium-navigation/src/main/java/com/joaquimverges/helium/navigation/toolbar/CollapsingToolbarUi.kt

@@ -7,9 +7,9 @@ import androidx.appcompat.app.ActionBar
 import androidx.appcompat.widget.Toolbar
 import com.google.android.material.appbar.AppBarLayout
 import com.google.android.material.appbar.CollapsingToolbarLayout
+import com.joaquimverges.helium.core.UiBlock
 import com.joaquimverges.helium.core.event.BlockEvent
 import com.joaquimverges.helium.core.state.BlockState
-import com.joaquimverges.helium.core.UiBlock
 import com.joaquimverges.helium.navigation.R
 
 /**

helium-navigation/src/main/java/com/joaquimverges/helium/navigation/toolbar/ScrollConfiguration.kt

@@ -2,6 +2,8 @@ package com.joaquimverges.helium.navigation.toolbar
 
 import com.google.android.material.appbar.AppBarLayout
 import com.google.android.material.appbar.CollapsingToolbarLayout
+import com.joaquimverges.helium.navigation.toolbar.ScrollConfiguration.CollapseMode
+import com.joaquimverges.helium.navigation.toolbar.ScrollConfiguration.ScrollMode
 
 /**
  * Configures the scrolling behavior for a [CollapsingToolbarUi]

helium-navigation/src/main/java/com/joaquimverges/helium/navigation/toolbar/ToolbarUi.kt

@@ -8,8 +8,8 @@ import androidx.annotation.MenuRes
 import androidx.appcompat.app.ActionBar
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.widget.Toolbar
-import com.joaquimverges.helium.core.state.BlockState
 import com.joaquimverges.helium.core.UiBlock
+import com.joaquimverges.helium.core.state.BlockState
 import com.joaquimverges.helium.navigation.R
 
 /**

helium-test/build.gradle

@@ -48,8 +48,9 @@ dependencies {
     api "androidx.test.ext:junit:$test_ext_version"
     api "androidx.test.ext:junit-ktx:$test_ext_version"
     api "androidx.test.espresso:espresso-core:$test_espresso_version"
-    api "com.nhaarman:mockito-kotlin:$mockito_kotlin_version"
+    api "com.nhaarman.mockitokotlin2:mockito-kotlin:$mockito_kotlin_version"
     api "org.robolectric:robolectric:$robolectric_version"
+    api "org.jetbrains.kotlinx:kotlinx-coroutines-test:$coroutines_version"
     implementation project(':helium-core')
 }