Dependency Injection in Android with Hilt

An introduction about Hilt. We will also cover the importance of Dependency Injection to create a solid and extensible application that scales to large projects.

Transcript

1. GDG Location
2. GDG Location What is DI ?
3. GDG Location • Reduces the boilerplate code • Makes our code reusable and clean • Make testing easier • Ease of refactoring DI advantages
4. GDG Location // No Dependency Injection class Car { private val engine = Engine() fun start() {...} }
5. GDG Location // No Dependency Injection class Car { private val engine = Engine() fun start() {...} } fun main() { val car = Car() car.start() }
6. GDG Location // With Dependency Injection class Car(private val engine: Engine) { fun start() {...} }
7. GDG Location // With Dependency Injection class Car(private val engine: Engine) { fun start() {...} } fun main() { val engine = Engine() val car = Car(engine) car.start() }
8. GDG Location DI in Android Many ways to do it... Kodein Koin Dagger ...
9. GDG Location Hilt
10. GDG Location Hilt • Standardize DI in Android • Build on top of Dagger • Tooling Support • AndroidX Extensions
11. GDG Location Setup buildscript { ... dependencies { ... classpath 'com.google.dagger:hilt-android-gradle-plugin:2.28-alpha' } } build.gradle (project)
12. GDG Location Setup apply plugin: 'kotlin-kapt' apply plugin: 'dagger.hilt.android.plugin' //... dependencies { implementation "com.google.dagger:hilt-android:2.28-alpha" kapt "com.google.dagger:hilt-android-compiler:2.28-alpha" } build.gradle (app)
13. GDG Location Hilt annotations • @HiltAndroidApp • @Inject • @AndroidEntryPoint • @InstallIn • ...
14. GDG Location @HiltAndroidApp class CarApplication : Application()
15. GDG Location class Car @Inject constructor() { fun start() { } }
16. GDG Location class Car @Inject constructor() { fun start() { } } @AndroidEntryPoint class CarActivity: AppCompatActivity(){ }
17. GDG Location class Car @Inject constructor() { fun start() { } } @AndroidEntryPoint class CarActivity: AppCompatActivity(){ @Inject lateinit var car: Car }
18. GDG Location class Car @Inject constructor() { fun start() { } } @AndroidEntryPoint class CarActivity: AppCompatActivity(){ @Inject lateinit var car: Car override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) car.start() } }
19. GDG Location Components
20. GDG Location Components
21. GDG Location Hilt Module When Interface 3rd party lib Configuration
22. GDG Location class Car @Inject constructor( private val db: CarDB ) { ... }
23. GDG Location @Module @InstallIn(ApplicationComponent::class) object DataModule{ @Provides fun provideCardDB(@ApplicationContext context: Context) = Room.databaseBuilder(context,CarDB::class.java,"car.db") .build() }
24. GDG Location @Module @InstallIn(ApplicationComponent::class) object DataModule{ @Provides fun provideCardDB(@ApplicationContext context: Context) = Room.databaseBuilder(context,CarDB::class.java,"card.db") .build() }
25. GDG Location @Module @InstallIn(ApplicationComponent::class) object DataModule{ @Provides @Singleton fun provideCardDB(@ApplicationContext context: Context) = Room.databaseBuilder(context,CarDB::class.java,"card.db") .build() }
26. GDG Location AndroidX Extensions class CarViewModel @ViewModelInject constructor( private val db: CarDB ) : ViewModel() { ... }
27. GDG Location AndroidX Extensions class CarViewModel @ViewModelInject constructor( private val db: CarDB ) : ViewModel() { ... } @AndroidEntryPoint class CarActivity0 : AppCompatActivity() { val viewModel: CarViewModel by ViewModels() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) viewModel.start() } }
28. GDG Location Resources • Using Hilt in your Android app [https://cutt.ly/3fsTeno] • Migrating your Dagger app to Hilt [https://cutt.ly/1fsTiU7]
29. Thank you!