Migrate From LiveData to Coroutines Flows & Channels

README.md

@@ -4,42 +4,53 @@
 
 ### API Key
 
-To run the application you need to supply an API key from [TMBD](https://developers.themoviedb.org/3/getting-started/introduction). When you get the key please add following variable to your local environment:
+To run the application you need to supply an API key
+from [TMBD](https://developers.themoviedb.org/3/getting-started/introduction). When you get the key
+please add following variable to your local environment:
 
 `` API_KEY_TMDB = Your API Key ``
 
-How to set an environment variable in [Mac](https://medium.com/@himanshuagarwal1395/setting-up-environment-variables-in-macos-sierra-f5978369b255) / [Windows](https://www.architectryan.com/2018/08/31/how-to-change-environment-variables-on-windows-10/)
+How to set an environment variable
+in [Mac](https://medium.com/@himanshuagarwal1395/setting-up-environment-variables-in-macos-sierra-f5978369b255) / [Windows](https://www.architectryan.com/2018/08/31/how-to-change-environment-variables-on-windows-10/)
 
 ### Code style [*](https://github.com/VMadalin/kotlin-sample-app)
 
-To maintain the style and quality of the code, are used the bellow static analysis tools. All of them use properly configuration and you find them in the project root directory `config/.{toolName}`.
+To maintain the style and quality of the code, are used the bellow static analysis tools. All of
+them use properly configuration and you find them in the project root
+directory `config/.{toolName}`.
 
-| Tools                             | Config file                            | Check command                | Fix command               |
-|-----------------------------------|---------------------------------------:|------------------------------|---------------------------|
-| [detekt][detekt]                  | [.detekt.yml](/config/.detekt.yml)     | `./gradlew detekt`           | -                         |
-| [ktlint][ktlint]                  | -                                      | `./gradlew ktlint`           | `./gradlew ktlintFormat`  |
-| [spotless][spotless]              | -                                      | `./gradlew spotlessCheck`    | `./gradlew spotlessApply` |
-| [lint][lint]                      | [.lint.xml](/config/.lint.xml)         | `./gradlew lint`             | -                         |
-| [gradle versions plugin][gvPlugin]| -                                      | `./gradlew dependencyUpdates`| -                         |
+| Tools                              |                        Config file | Check command                 | Fix command               |
+|------------------------------------|-----------------------------------:|-------------------------------|---------------------------|
+| [detekt][detekt]                   | [.detekt.yml](/config/.detekt.yml) | `./gradlew detekt`            | -                         |
+| [ktlint][ktlint]                   |                                  - | `./gradlew ktlint`            | `./gradlew ktlintFormat`  |
+| [spotless][spotless]               |                                  - | `./gradlew spotlessCheck`     | `./gradlew spotlessApply` |
+| [lint][lint]                       |     [.lint.xml](/config/.lint.xml) | `./gradlew lint`              | -                         |
+| [gradle versions plugin][gvPlugin] |                                  - | `./gradlew dependencyUpdates` | -                         |
 
-All these tools, except [Gradle Versions Plugin][gvPlugin], are integrated in [pre-commit git hook](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks), in order
-ensure that all static analysis and tests passes before you can commit your changes. [Gradle Versions Plugin][gvPlugin] can be run optionally. To skip them for specific commit add this option at your git command:
+All these tools, except [Gradle Versions Plugin][gvPlugin], are integrated
+in [pre-commit git hook](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks), in order
+ensure that all static analysis and tests passes before you can commit your
+changes. [Gradle Versions Plugin][gvPlugin] can be run optionally. To skip them for specific commit
+add this option at your git command:
 
 ```properties
 git commit --no-verify
 ```
 
-It's highly recommended to fix broken code styles. There is [a gradle task](/build.gradle#L57) which execute `ktlintFormat` and `spotlessApply` for you:
+It's highly recommended to fix broken code styles. There is [a gradle task](/build.gradle#L57) which
+execute `ktlintFormat` and `spotlessApply` for you:
 
 ```properties
 ./gradlew reformat
 ```
 
+The pre-commit git hooks have exactly the same checks as [CircleCI](https://circleci.com/) and are
+defined in this [script](/config/scripts/git-hooks/pre-commit.sh). This step ensures that all
+commits comply with the established rules. However the continuous integration will ultimately be
+validated that the changes are correct.
 
-The pre-commit git hooks have exactly the same checks as [CircleCI](https://circleci.com/) and are defined in this [script](/config/scripts/git-hooks/pre-commit.sh). This step ensures that all commits comply with the established rules. However the continuous integration will ultimately be validated that the changes are correct.
-
-
-If you want to know more about naming convention, code style and more please look at our [Android guideline](https://github.com/adessoTurkey/android-guideline) repository.
+If you want to know more about naming convention, code style and more please look at
+our [Android guideline](https://github.com/adessoTurkey/android-guideline) repository.
 
 ## Architecture
 
@@ -50,7 +61,8 @@ If you want to know more about naming convention, code style and more please loo
 
 **ViewModel:** Can have simple UI logic but most of the time just gets the data from UseCase
 
-**UseCase:** Contains all business rules and they written in the manner of single responsibility principle
+**UseCase:** Contains all business rules and they written in the manner of single responsibility
+principle
 
 **Repository:** Single source of data. Responsible to get data from one or more data sources
 
@@ -60,10 +72,13 @@ If you want to know more about naming convention, code style and more please loo
 
 #### Dependencies
 
-- **[Navigation Component](https://developer.android.com/jetpack/androidx/releases/navigation):** Consistent navigation between views
-- **[LiveData](https://developer.android.com/topic/libraries/architecture/livedata):** Lifecycle aware observable and data holder
-- **[ViewModel](https://developer.android.com/topic/libraries/architecture/viewmodel):** Holds UI data across configuration changes
-- **[Databinding](https://developer.android.com/topic/libraries/data-binding/):** Binds UI components in layouts to data sources
+- **[Navigation Component](https://developer.android.com/jetpack/androidx/releases/navigation):**
+  Consistent navigation between views
+- **[Flow](https://developer.android.com/kotlin/flow):** Asynchronous data streams
+- **[ViewModel](https://developer.android.com/topic/libraries/architecture/viewmodel):** Holds UI
+  data across configuration changes
+- **[Databinding](https://developer.android.com/topic/libraries/data-binding/):** Binds UI
+  components in layouts to data sources
 - **[Dagger](https://github.com/google/dagger):** Dependency injector
 - **[Coroutines](https://github.com/Kotlin/kotlinx.coroutines):** Asynchronous programming
 - **[Glide](https://github.com/bumptech/glide):** Image loading and caching
@@ -100,7 +115,11 @@ limitations under the License.
 ```
 
 [detekt]: https://github.com/arturbosch/detekt
+
 [ktlint]: https://github.com/pinterest/ktlint
-[spotless]: https://github.com/diffplug/spotless       
+
+[spotless]: https://github.com/diffplug/spotless
+
 [lint]: https://developer.android.com/studio/write/lint
+
 [gvPlugin]: https://github.com/ben-manes/gradle-versions-plugin

app/src/main/kotlin/com/adesso/movee/base/BaseAndroidViewModel.kt

@@ -4,31 +4,32 @@ import android.annotation.SuppressLint
 import android.app.Application
 import androidx.annotation.StringRes
 import androidx.lifecycle.AndroidViewModel
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.viewModelScope
 import androidx.navigation.NavDirections
 import com.adesso.movee.R
 import com.adesso.movee.internal.popup.PopUpType
 import com.adesso.movee.internal.popup.PopupCallback
 import com.adesso.movee.internal.popup.PopupUiModel
-import com.adesso.movee.internal.util.Event
 import com.adesso.movee.internal.util.Failure
 import com.adesso.movee.navigation.NavigationCommand
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.withContext
 
 @SuppressLint("StaticFieldLeak")
 abstract class BaseAndroidViewModel(application: Application) : AndroidViewModel(application) {
 
-    private val _failurePopup = MutableLiveData<Event<PopupUiModel>>()
-    val failurePopup: LiveData<Event<PopupUiModel>> = _failurePopup
+    private val _failurePopup = Channel<PopupUiModel>(Channel.CONFLATED)
+    val failurePopup = _failurePopup.receiveAsFlow()
 
-    private val _success = MutableLiveData<Event<String>>()
-    val success: LiveData<Event<String>> = _success
+    private val _success = Channel<String>(Channel.CONFLATED)
+    val success = _success.receiveAsFlow()
 
-    private val _navigation = MutableLiveData<Event<NavigationCommand>>()
-    val navigation: LiveData<Event<NavigationCommand>> = _navigation
+    private val _navigation = Channel<NavigationCommand>(Channel.CONFLATED)
+    val navigation = _navigation.receiveAsFlow()
 
     protected open fun handleFailure(failure: Failure) {
         val (title, message) = when (failure) {
@@ -65,7 +66,7 @@ abstract class BaseAndroidViewModel(application: Application) : AndroidViewModel
             else -> Pair("", failure.message ?: failure.toString())
         }
 
-        _failurePopup.value = Event(
+        _failurePopup.trySend(
             PopupUiModel(
                 title = title,
                 message = message,
@@ -75,27 +76,27 @@ abstract class BaseAndroidViewModel(application: Application) : AndroidViewModel
     }
 
     protected fun showSnackBar(message: String) {
-        _success.value = Event(message)
+        _success.trySend(message)
     }
 
     fun navigate(directions: NavDirections) {
-        _navigation.value = Event(NavigationCommand.ToDirection(directions))
+        _navigation.trySend(NavigationCommand.ToDirection(directions))
     }
 
     fun navigate(deepLink: String) {
-        _navigation.value = Event(NavigationCommand.ToDeepLink(deepLink))
+        _navigation.trySend(NavigationCommand.ToDeepLink(deepLink))
     }
 
     fun navigate(@StringRes deepLinkRes: Int) {
         navigate(getString(deepLinkRes))
     }
 
     fun navigate(model: PopupUiModel, callback: PopupCallback?) {
-        _navigation.value = Event(NavigationCommand.Popup(model, callback))
+        _navigation.trySend(NavigationCommand.Popup(model, callback))
     }
 
     fun navigateBack() {
-        _navigation.value = Event(NavigationCommand.Back)
+        _navigation.trySend(NavigationCommand.Back)
     }
 
     protected suspend fun <T> runOnViewModelScope(block: suspend CoroutineScope.() -> T): T {

app/src/main/kotlin/com/adesso/movee/base/BaseBottomSheetDialogFragment.kt

@@ -18,7 +18,7 @@ import androidx.navigation.fragment.FragmentNavigatorExtras
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.navGraphViewModels
 import com.adesso.movee.BR
-import com.adesso.movee.internal.extension.observeNonNull
+import com.adesso.movee.internal.extension.collectFlow
 import com.adesso.movee.internal.extension.showPopup
 import com.adesso.movee.internal.util.functional.lazyThreadSafetyNone
 import com.adesso.movee.navigation.NavigationCommand
@@ -88,10 +88,9 @@ abstract class BaseBottomSheetDialogFragment<VM : BaseAndroidViewModel, B : View
     }
 
     private fun observeNavigation() {
-        viewModel.navigation.observeNonNull(viewLifecycleOwner) {
-            it.getContentIfNotHandled()?.let { command ->
-                handleNavigation(command)
-            }
+
+        collectFlow(viewModel.navigation) { command ->
+            handleNavigation(command)
         }
     }
 
@@ -100,33 +99,36 @@ abstract class BaseBottomSheetDialogFragment<VM : BaseAndroidViewModel, B : View
             is NavigationCommand.ToDirection -> {
                 findNavController().navigate(command.directions, getExtras())
             }
+
             is NavigationCommand.ToDeepLink -> {
                 (activity as? MainActivity)
                     ?.navController
                     ?.navigate(command.deepLink.toUri(), null, getExtras())
             }
+
             is NavigationCommand.Popup -> {
                 with(command) {
                     context?.showPopup(model, callback)
                 }
             }
+
             is NavigationCommand.Back -> findNavController().navigateUp()
         }
     }
 
     private fun observeFailure() {
-        viewModel.failurePopup.observeNonNull(viewLifecycleOwner) {
-            it.getContentIfNotHandled()?.let { popupUiModel ->
-                context?.showPopup(popupUiModel)
-            }
+
+        collectFlow(viewModel.failurePopup) { popupUiModel ->
+
+            context?.showPopup(popupUiModel)
         }
     }
 
     private fun observeSuccess() {
-        viewModel.success.observeNonNull(viewLifecycleOwner) {
-            it.getContentIfNotHandled()?.let { message ->
-                showSnackBarMessage(message)
-            }
+
+        collectFlow(viewModel.success) { message ->
+
+            showSnackBarMessage(message)
         }
     }
 

app/src/main/kotlin/com/adesso/movee/base/BaseFragment.kt

@@ -15,7 +15,8 @@ import androidx.navigation.fragment.FragmentNavigator
 import androidx.navigation.fragment.FragmentNavigatorExtras
 import androidx.navigation.fragment.findNavController
 import com.adesso.movee.BR
-import com.adesso.movee.internal.extension.observeNonNull
+import com.adesso.movee.internal.extension.collectFlow
+import com.adesso.movee.internal.extension.collectFlowNonNull
 import com.adesso.movee.internal.extension.showPopup
 import com.adesso.movee.navigation.NavigationCommand
 import com.adesso.movee.scene.main.MainActivity
@@ -70,10 +71,10 @@ abstract class BaseFragment<VM : BaseAndroidViewModel, B : ViewDataBinding> : Fr
     }
 
     private fun observeNavigation() {
-        viewModel.navigation.observeNonNull(viewLifecycleOwner) {
-            it.getContentIfNotHandled()?.let { command ->
-                handleNavigation(command)
-            }
+
+        collectFlow(viewModel.navigation) { command ->
+
+            handleNavigation(command)
         }
     }
 
@@ -100,18 +101,18 @@ abstract class BaseFragment<VM : BaseAndroidViewModel, B : ViewDataBinding> : Fr
     }
 
     private fun observeFailure() {
-        viewModel.failurePopup.observeNonNull(viewLifecycleOwner) {
-            it.getContentIfNotHandled()?.let { popupUiModel ->
-                context?.showPopup(popupUiModel)
-            }
+
+        collectFlow(viewModel.failurePopup) { popupUiModel ->
+
+            context?.showPopup(popupUiModel)
         }
     }
 
     private fun observeSuccess() {
-        viewModel.success.observeNonNull(viewLifecycleOwner) {
-            it.getContentIfNotHandled()?.let { message ->
-                showSnackBarMessage(message)
-            }
+
+        collectFlowNonNull(viewModel.success) { message ->
+
+            showSnackBarMessage(message)
         }
     }
 

app/src/main/kotlin/com/adesso/movee/internal/extension/Activity.kt

@@ -3,6 +3,9 @@ package com.adesso.movee.internal.extension
 import android.app.Activity
 import android.content.Context
 import android.view.inputmethod.InputMethodManager
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import kotlinx.coroutines.flow.Flow
 
 fun Activity.closeKeyboard() {
     currentFocus?.let { view ->
@@ -17,3 +20,19 @@ fun Activity.showKeyboard() {
         imm?.showSoftInput(view, InputMethodManager.SHOW_IMPLICIT)
     }
 }
+
+inline fun <T> Activity.collectFlow(
+    flow: Flow<T>,
+    minActiveState: Lifecycle.State = Lifecycle.State.STARTED,
+    crossinline action: suspend (T) -> Unit
+) {
+    flow.collectWithLifecycle(this as LifecycleOwner, minActiveState, action)
+}
+
+inline fun <T> Activity.collectFlowNonNull(
+    flow: Flow<T?>,
+    minActiveState: Lifecycle.State = Lifecycle.State.STARTED,
+    crossinline action: suspend (T) -> Unit
+) {
+    flow.collectWithLifecycleNonNull(this as LifecycleOwner, minActiveState, action)
+}

app/src/main/kotlin/com/adesso/movee/internal/extension/Flow.kt

@@ -0,0 +1,53 @@
+package com.adesso.movee.internal.extension
+
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.flowWithLifecycle
+import androidx.lifecycle.lifecycleScope
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.launch
+
+inline fun <T> Flow<T>.collect(
+    scope: CoroutineScope,
+    crossinline action: suspend (T) -> Unit
+) {
+    scope.launch {
+        collect { action(it) }
+    }
+}
+
+inline fun <T> Flow<T?>.collectNonNull(
+    scope: CoroutineScope,
+    crossinline action: suspend (T) -> Unit
+) {
+    scope.launch {
+        collect { value ->
+            value?.let { action(it) }
+        }
+    }
+}
+
+inline fun <T> Flow<T>.collectWithLifecycle(
+    lifecycleOwner: LifecycleOwner,
+    minActiveState: Lifecycle.State = Lifecycle.State.STARTED,
+    crossinline action: suspend (T) -> Unit
+) {
+    lifecycleOwner.lifecycleScope.launch {
+        flowWithLifecycle(lifecycleOwner.lifecycle, minActiveState)
+            .collect { action.invoke(it) }
+    }
+}
+
+inline fun <T> Flow<T?>.collectWithLifecycleNonNull(
+    lifecycleOwner: LifecycleOwner,
+    minActiveState: Lifecycle.State = Lifecycle.State.STARTED,
+    crossinline action: suspend (T) -> Unit
+) {
+    lifecycleOwner.lifecycleScope.launch {
+        flowWithLifecycle(lifecycleOwner.lifecycle, minActiveState)
+            .collect { value ->
+                value?.let { action.invoke(it) }
+            }
+    }
+}