Android Developer Advocate @ Stream Exploring Now in Android Jaewoong

skydoves @github_skydoves Android Developer Advocate @ Stream Jaewoong Eum Google Developer Expert

Now in Android

Now in Android

Now in Android Exploring Tech Stacks

Tech Stacks ● 100% Compose (activity, foundation, material3, accompanist) ● Navigation (Compose, Hilt) ● WindowManager ● Coil User Interface 01

Tech Stacks ● 100% Compose (activity, foundation, material3, accompanist) ● Navigation (Compose, Hilt) ● WindowManager ● Coil User Interface 01 ● DataStore ● Room Database ● Retrofit ● Kotlin Serialization ● Kotlin Coroutines ● WorkManager Business Works 02

Tech Stacks ● 100% Compose (activity, foundation, material3, accompanist) ● Navigation (Compose, Hilt) ● WindowManager ● Coil User Interface 01 ● DataStore ● Room Database ● Retrofit ● Kotlin Serialization ● Kotlin Coroutines ● WorkManager Business Works 02 ● Baseline Profiles ● Macrobenchmark ● Hilt ● App Startup Other Jetpacks 03

Now in Android Exploring App Architecture

Architecture Overview Unidirectional Data Flow ● Higher layers react to changes in lower layers. ● Events flow down. ● Data flows up with data streams. (Kotlin Flows) Unidirectional Event Flow

Architecture - UI Layer

Architecture - UI Layer

Architecture - UI Layer

Architecture - UI Layer Modeling UI state ● UI state always represents the underlying app data. ● UI elements handle all possible states. Transforming streams into UI state ● View models receive streams of data as Flows from data layers. ● The single flow is converted to StateFlows, which enables UI elements to read the last state. Processing user interactions (Unidirectional event flow) ● User actions are communicated from UI elements to view models. ● View models execute business logic following the user interactions.

Architecture - Data Layer

Architecture - Data Layer UI layers must be prepared to react to data changes.

Reads are performed from local storage as the single source of truth. Architecture - Data Layer

A single source of truth principle is a philosophy of aggregating the data from many systems within an organization to a single location. Architecture - Data Layer

Architecture - Data Layer

interface Syncable { /** * Synchronizes the local database backing the repository with the network. * Returns if the sync was successful or not. */ suspend fun syncWith(synchronizer: Synchronizer): Boolean } Architecture - Sync

interface Syncable { /** * Synchronizes the local database backing the repository with the network. * Returns if the sync was successful or not. */ suspend fun syncWith(synchronizer: Synchronizer): Boolean } Architecture - Sync interface TopicsRepository : Syncable class OfflineFirstTopicsRepository @Inject constructor( .. ) : TopicsRepository { override suspend fun syncWith(synchronizer: Synchronizer): Boolean = synchronizer.changeListSync( ..

interface Syncable { /** * Synchronizes the local database backing the repository with the network. * Returns if the sync was successful or not. */ suspend fun syncWith(synchronizer: Synchronizer): Boolean } Architecture - Sync interface TopicsRepository : Syncable class OfflineFirstTopicsRepository @Inject constructor( .. ) : TopicsRepository { override suspend fun syncWith(synchronizer: Synchronizer): Boolean = synchronizer.changeListSync( .. Versioning each model

@HiltWorker class SyncWorker @AssistedInject constructor( ... ) : CoroutineWorker(appContext, workerParams), Synchronizer { override suspend fun doWork(): Result = withContext(ioDispatcher) { // First sync the repositories in parallel val syncedSuccessfully = awaitAll( async { topicRepository.syncWith(this) }, async { authorsRepository.syncWith(this) }, async { newsRepository.syncWith(this) }, ).all { it } if (syncedSuccessfully) Result.success() else Result.retry() } Architecture - Sync

@HiltWorker class SyncWorker @AssistedInject constructor( ... ) : CoroutineWorker(appContext, workerParams), Synchronizer { override suspend fun doWork(): Result = withContext(ioDispatcher) { // First sync the repositories in parallel val syncedSuccessfully = awaitAll( async { topicRepository.syncWith(this) }, async { authorsRepository.syncWith(this) }, async { newsRepository.syncWith(this) }, ).all { it } if (syncedSuccessfully) Result.success() else Result.retry() } Architecture - Sync Synchronize all repositories

class SyncInitializer : Initializer { override fun create(context: Context): Sync { WorkManager.getInstance(context).apply { // Run sync on app startup and ensure only one sync worker runs at any time enqueueUniqueWork( SyncWorkName, ExistingWorkPolicy.REPLACE, SyncWorker.startUpSyncWork() ) } return Sync } override fun dependencies(): List>> = .. } Architecture - Sync Returns OneTimeWorkRequest

Architecture - Sync

Architecture - ForYou Screen

Architecture - ForYou Screen

Architecture - ForYou Screen

Architecture - ForYou Screen

Architecture - ForYou Screen The recommendations and best practices present in this architecture can be applied to a broad spectrum of apps to allow them to scale, improve quality and robustness, and make them easier to test. However, you should treat them as guidelines and adapt them to your requirements as needed.

Now in Android Exploring UI Layers with Compose

UI Layer - Material You

UI Layer - Material You Dynamic color extraction algorithm

UI Layer - Material You ● Material Theme ● Material Components ● Dynamic Color Scheme

UI Layer - Material You

UI Layer - Material You

UI Layer - Material You

UI Layer - Material You

Material Theme (Color Scheme) ● Primary ● onPrimary ● PrimaryContainer ● onPrimaryContainer ● Secondary ● onSecondary ● Tertiary ● onTertiary ● Bacground ● onBackground ● Surface ● onSurface ● SurfaceVariant ● onSurfaceVariant … UI Layer - Theming

UI Layer - Theming Dynamic Theme Light Dark Custom Theme Default Theme Android 12 Specific General

private val LightDefaultColorScheme = lightColorScheme( primary = Purple40, onPrimary = Color.White, … private val DarkDefaultColorScheme = darkColorScheme( primary = Purple80, onPrimary = Purple20, … private val LightAndroidColorScheme = lightColorScheme( primary = Green40, onPrimary = Color.White, … private val DarkAndroidColorScheme = darkColorScheme( primary = Green80, onPrimary = Green20, …. UI Layer - Theming

@Composable fun NiaTheme( darkTheme: Boolean = isSystemInDarkTheme(), dynamicColor: Boolean = false, androidTheme: Boolean = false, content: @Composable() () -> Unit ) { val colorScheme = when { dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> { val context = LocalContext.current if (darkTheme) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context) } androidTheme && darkTheme -> DarkAndroidColorScheme androidTheme -> LightAndroidColorScheme darkTheme -> DarkDefaultColorScheme else -> LightDefaultColorScheme } UI Layer - Theming

@Composable fun NiaTheme( darkTheme: Boolean = isSystemInDarkTheme(), dynamicColor: Boolean = false, androidTheme: Boolean = false, content: @Composable() () -> Unit ) { val colorScheme = when { dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> { val context = LocalContext.current if (darkTheme) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context) } androidTheme && darkTheme -> DarkAndroidColorScheme androidTheme -> LightAndroidColorScheme darkTheme -> DarkDefaultColorScheme else -> LightDefaultColorScheme } UI Layer - Theming

@Composable fun NiaTheme( darkTheme: Boolean = isSystemInDarkTheme(), dynamicColor: Boolean = false, androidTheme: Boolean = false, content: @Composable() () -> Unit ) { val colorScheme = when { dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> { val context = LocalContext.current if (darkTheme) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context) } androidTheme && darkTheme -> DarkAndroidColorScheme androidTheme -> LightAndroidColorScheme darkTheme -> DarkDefaultColorScheme else -> LightDefaultColorScheme } UI Layer - Theming

UI Layer - Large Screen The large screens of tablets, foldables, and Chrome OS devices

UI Layer - Large Screen https://bit.ly/3Q0HGoS

UI Layer - Large Screen

dependencies { implementation "androidx.compose.material3:material3-window-size-class:1.0.0-alpha10" Implementation "androidx.window:window:1.0.0" } UI Layer - Large Screen

UI Layer - Large Screen

UI Layer - Large Screen

UI Layer - Large Screen

UI Layer - Large Screen

UI Layer - Large Screen Navigation Rail

UI Layer - Large Screen Compact Medium, Expanded

Now in Android Exploring App Performance

UI Layer - Compose Phases Which UI to draw Where to place UI. Measurement and placement How it renders

UI Layer - Recomposition

Composable functions can use the remember API to store an object in memory. A value computed by remember is stored in the Composition during initial composition, and the stored value is returned during recomposition. UI Layer - Remember

UI Layer - Remember

UI Layer - Remember High costs in every recomposition

UI Layer - Remember Recompose when key values changed

UI Layer - Lazy Lists Column LazyColumn

UI Layer - Lazy Lists

UI Layer - Lazy Lists

UI Layer - Lazy Lists

UI Layer - Lazy Lists

Performance - Baseline Profiles It seems to be janky for the first couple of seconds!

Performance - Baseline Profiles Compose is a library — it does not participate in system resource sharing.

Performance - Baseline Profiles Baseline Profiles Android Runtime

Performance - Baseline Profiles

Performance - Baseline Profiles

Performance - Baseline Profiles Total: 7059 lines (baseline-prof.txt) HSPLandroidx/compose/animation/AndroidFlingSpline$FlingResult;->(FF)V HSPLandroidx/compose/animation/AndroidFlingSpline;->()V HSPLandroidx/compose/animation/AndroidFlingSpline;->()V HSPLandroidx/compose/animation/AndroidFlingSpline;->flingPosition(F)Landroidx/compose/animation/AndroidFlingSpline$FlingResult; HSPLandroidx/compose/animation/CrossfadeKt$$ExternalSyntheticOutline0;->m(Landroidx/compose/runtime/Composer;)V HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$1;->(Ljava/lang/Object;Landroidx/compose/ui/Modifier;Landroidx/comp ose/animation/core/FiniteAnimationSpec;Lkotlin/jvm/functions/Function3;II)V HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$1;->invoke(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object; HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$2;->()V HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$2;->()V HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$2;->invoke(Ljava/lang/Object;)Ljava/lang/Object; HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$3$1;->(Landroidx/compose/animation/core/Transition;)V HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$3$1;->invoke(Ljava/lang/Object;)Ljava/lang/Object; HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$4$1$$ExternalSyntheticOutline0;->m(Landroidx/compose/runtime/Compose r;III)V HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$4$1$1$1;->(Landroidx/compose/runtime/State;)V HSPLandroidx/compose/animation/CrossfadeKt$Crossfade$4$1$1$1;->invok HSPLandroidx/compose/animation/CrossfadeKt;->Crossfade(Landroidx/compose/animation/core/Transition;Landroidx/compose/ui/Modifier; Landroidx/compose/animation/core/FiniteAnimationSpec;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function3;Landroidx/compose /runtime/Composer;II)V ….

References ● Now in Android ○ https://github.com/android/nowinandroid ● Exploring App Architecture ○ https://github.com/android/nowinandroid/blob/main/docs/ArchitectureLearningJourney.md ● Exploring UI Layer ○ https://material.io/blog/start-building-with-material-you ○ https://getstream.io/blog/material-you-jetpack-compose/ ○ https://getstream.io/blog/jetpack-windowmanager-foldable/ ○ https://developer.android.com/guide/topics/large-screens/support-different-screen-sizes ○ https://youtu.be/EOQB8PTLkpY ○ https://developer.android.com/jetpack/compose/performance ● Performance ○ https://developer.android.com/jetpack/compose/phases ○ https://developer.android.com/topic/performance/baselineprofiles ○ https://developer.android.com/topic/performance/benchmarking/macrobenchmark-overview

Thank you! Android Developer Advocate @ GetStream Google Developer Expert skydoves skydoves2@gmail.com @github_skydoves Contacts Jaewoong Eum