Building Mobile Apps and Scaling them

Transcript

1. Building Mobile Apps and Scaling Them
2. Subhrajyoti Sen Android GDE | Motive @iamsubhrajyoti
3. Design Systems
4. What is a Design System? A design system is a collection of reusable components, guidelines, and assets that help maintain consistency in the design and development of an app or website. It acts as a single source of truth for UI and UX elements.
5. Keys Part of a Design System • Typography hierarchy • Color palette and accessibility considerations • Spacing system • Component library (buttons, cards, navigation elements)
6. Why Jetpack Compose? • Less code • Powerful • Intuitive • Faster development
7. Previews @Preview @Composable fun BorrowedItemRowPreview() { BorrowedItemRow( item = BorrowItem( id = 0, itemName = "XBox Series X", borrowerName = "Steve", borrowDate = "2-11-2023" ) ) }
8. Previews @Preview @Composable fun BorrowedItemRowPreview() { BorrowedItemRow( item = BorrowItem( id = 0, itemName = "XBox Series X", borrowerName = "Steve", borrowDate = "2-11-2023" ) ) }
9. Previews
11. Playground Apps • Better discoverability • Easy of testing
12. Showkase • Annotation-process based library • Developed by Airbnb • Visualize components, colors and text styles
13. @ShowkaseComposable(group = "Individual rows") @Preview @Composable fun BorrowedItemRowExpandedPreview() { BorrowTheme { BorrowedItemRow( //.. ) } }
14. @ShowkaseComposable(group = "Individual rows") @Preview @Composable fun BorrowedItemRowExpandedPreview() { BorrowTheme { BorrowedItemRow( //.. ) } }
18. Feature Flags
19. What is a Feature Flag? A feature flag (also called a feature toggle) is a software development technique used to enable or disable specific features in an app without changing the code or releasing a new version.
20. Why use Feature Flags? • Gradual Rollouts • A/B Testing • Kill Switch • Remote Configuration
21. val featureEnabled = Firebase.remoteConfig.getBoolean("feature_name") if (featureEnabled) { // Show feature UI } else { // Hide feature UI }
22. interface Feature { val key: String val defaultValue: Boolean }
23. enum class RemoteFeature( override val key: String, override val defaultValue: Boolean, )
24. enum class RemoteFeature() : Feature { DARK_MODE( key = "dark_mode", defaultValue = true ) }
25. interface FeatureFlagProvider { val key: String fun isFeatureEnabled(feature: Feature): Boolean fun containsFeature(feature: Feature): Boolean }
26. class FirebaseFlagProvider() : FeatureFlagProvider { override val key: String = "firebase" val remoteConfig: FirebaseRemoteConfig = //.. override fun isFeatureEnabled(feature: Feature): Boolean { // .. } override fun containsFeature(feature: Feature): Boolean { // .. } }
27. object FeatureManager { fun init(providers: List<FeatureFlagProvider>) { // add providers } fun isEnabled(feature: Feature): Boolean { // .. } }
28. val featureEnabled = Firebase.remoteConfig.getBoolean("feature_name") if (featureEnabled) { // Show feature UI } else { // Hide feature UI }
29. val featureEnabled = FeatureManager.isEnabled(RemoteFeature.DARK_MODE) if (featureEnabled) { // Show feature UI } else { // Hide feature UI }
30. Logging/Analytics
31. What Should You Log? • Crashes • Non-fatals • User flows
32. User Journeys • Navigation • Details entered • Time spent • Don’t log PII
33. Optimizing Project Structure
35. Gradle Optimizations • Use Gradle build Cache • Use Gradle Configuration Cache • Check the plugins and their impact • Use up-to-date Gradle and Android Gradle Plugin (AGP)
36. Performance
37. Local Performance • Write benchmark tests • Systrace • Battery Historian
38. Benchmark Test • Use Jetpack Microbenchmark • Test critical flows • Run periodically on the CI
39. @LargeTest @RunWith(AndroidJUnit4::class) class SampleStartupBenchmark { @get:Rule val benchmarkRule = MacrobenchmarkRule() @Test fun startup() = { //. } }
40. @LargeTest @RunWith(AndroidJUnit4::class) class SampleStartupBenchmark { @get:Rule val benchmarkRule = MacrobenchmarkRule() @Test fun startup() = { //. } }
41. @Test fun startup() = benchmarkRule.measureRepeated( packageName = Constants.PACKAGE_NAME, metrics = listOf(StartupTimingMetric()), startupMode = StartupMode.COLD, iterations = 10, setupBlock = { pressHome() } ) { startActivityAndWait() }
42. Remote Performance • Firebase Performance • Instabug • measure.sh
43. Kotlin Multiplatform
44. Why Go Multiplatform? • Drastically reduce development time • Write business logic only once • Reduced time to triage and fix bugs • Write test once • Maybe, even share UI code
45. Why Kotlin Multiplatform • Developed by JetBrains, creators of Kotlin • Officially supported by Google • Open Source • Great community support
46. Share Piece of Logic
47. Share Logic and Keep UI Native
48. Share Both Logic and UI (alpha)
53. expect class DecimalFormat() { fun format(double: Double): String }
54. actual class DecimalFormat { actual fun format(double: Double): String { val formatter = NSNumberFormatter().apply { locale = NSLocale("en_US") } formatter.minimumFractionDigits = 0u formatter.numberStyle = 1u // Decimal return formatter.stringFromNumber(NSNumber(double))!! } }
55. actual class DecimalFormat { actual fun format(double: Double): String { val formatter = NSNumberFormatter().apply { locale = NSLocale("en_US") } formatter.minimumFractionDigits = 0u formatter.numberStyle = 1u // Decimal return formatter.stringFromNumber(NSNumber(double))!! } }
56. actual class DecimalFormat { actual fun format(double: Double): String { val df = NumberFormat.getNumberInstance(Locale.ROOT) as? JavaDecimalFormat ?: JavaDecimalFormat() df.isGroupingUsed = false df.isDecimalSeparatorAlwaysShown = false return df.format(double) } }
57. actual class DecimalFormat { actual fun format(double: Double): String { val df = NumberFormat.getNumberInstance(Locale.ROOT) as? JavaDecimalFormat ?: JavaDecimalFormat() df.isGroupingUsed = false df.isDecimalSeparatorAlwaysShown = false return df.format(double) } }
58. CI/CD
60. Some Common Solutions • GitHub Actions • CircleCI • Bitrise
62. Some Common Solutions • GitHub Actions • CircleCI • Bitrise • Tramline
63. Closing Notes • Use abstraction when possible • Try writing code once • Focus on performance early on • Automate wherever possible
64. Thank you! Subhrajyoti Sen @iamsubhrajyoti