Dagger 2 Android : Defeat the Dahaka DevFestND 2017

Ppt for DevFest New Delhi, 2017 (Noida Track) @ToTheNew

Github Demo : https://github.com/ragdroid/Dahaka
Medium Blogs : https://proandroiddev.com/dagger-2-android-defeat-the-dahaka-b1c542233efc

Transcript

1. “Defeat the Dahaka" Dagger 2 Android Garima Jain @ragdroid
2. Garima Jain @ragdroid
3. Garima Jain @ragdroid
4. Garima Jain @ragdroid
5. Garima Jain @ragdroid
6. Garima Jain @ragdroid
7. Garima Jain @ragdroid
8. @ragdroid @droidconDE
9. @ragdroid @droidconDE MVP Testing DataBinding Retrofit Dagger 2
10. Garima Jain @ragdroid “Defeat the Dahaka" Dagger 2 Android
11. @ragdroid @droidconDE POP QUIZ • Dagger2? • Dagger Android • Prince of Persia
12. ABOUT THE TALK
13. Theme: Prince of Persia • Prince uses Dagger • Dagger can reverse time • Dahaka, (guardian of timeline) • Dahaka comes to kill the Prince.
14. Analogy • Prince = Us • Dagger = Dagger • Dahaka (Enemy) = Generated Code, Complexity
15. Analogy • Developer uses Dagger • Developer starts backtracking the generated code • Developer is chased by the Dahaka (complexity of generated code)
16. Agenda • Brief Introduction - “Codes of Time” • Scopes - “Face of the Dahaka” • @Singleton Scopes • @Reusable Scopes • Custom Scopes • Component Dependencies - “Unleash the Beast” • Demo App • Dependent Component • Subcomponent • Intermediate Concepts - “Defeat the Dahaka” • Dagger Android - “Befriend the Beast”
17. Who? • Assumption : Basic familiarity with Dagger • Intermediate
18. INTRODUCTION “CODES OF TIME”
19. @ragdroid @droidconDE Droid of Asia
20. @ragdroid @droidconDE public UserManager() {
 this.service = new PokemonService(); 
 } Droid of Asia
21. @ragdroid @droidconDE Dependency Creation Disadvantages • Non-Testable • Non-Extendable
22. @ragdroid @droidconDE Dagger 1
23. @ragdroid @droidconDE Dagger 1 Advantages • Testable code • Modularized
24. @ragdroid @droidconDE Dagger 1 Disadvantages • Reflection • Runtime Graph Composition • God Module with @Singleton • Difficult to use proguard
25. @ragdroid @droidconDE Dagger 1 Disadvantages Dagger 2
26. @ragdroid @droidconDE Dagger 2 Advantages • No Reflection • Compile-time Graph Composition • Traceable code • Better Scope management
27. SCOPES “FACE OF THE DAHAKA”
28. Scope • Annotation from java.inject package • How long a scoped instance lives
29. @Singleton • Scope of dependency is throughout the application • Two ways to re-use dependencies : • Annotate Provider methods • Annotate the Dependency class itself (javax.inject)
30. @ragdroid @droidconDE @SINGLETON VS NO SCOPE EXAMPLE
31. AppComponent @Component(modules = AppModule.class) @Singleton public interface AppComponent { SomeDependency someDependency(); }
32. AppComponent @Component(modules = AppModule.class) @Singleton public interface AppComponent { SomeDependency someDependency(); } AppComponent
33. @ragdroid @droidconDE CASE 1 DEPENDENCY W/O SCOPE
34. AppModule @Module public class AppModule { @Provides //No @Singleton annotation SomeDependency applicationProvider() { return new SomeDependency(); } }
35. AppModule @Module public class AppModule { @Provides //No @Singleton annotation SomeDependency applicationProvider() { return new SomeDependency(); } }
36. DaggerAppComponent @Generated public final class DaggerAppComponent implements AppComponent { private Provider<SomeDependency> someDependencyProvider; /** other code **/ private void initialize(final Builder builder) { this.someDependencyProvider = AppModule_SomeDependencyFactory.create(builder.appModule); } } (Generated)
37. DaggerAppComponent @Generated public final class DaggerAppComponent implements AppComponent { private Provider<SomeDependency> someDependencyProvider; /** other code **/ private void initialize(final Builder builder) { this.someDependencyProvider = AppModule_SomeDependencyFactory.create(builder.appModule); } } (Generated)
38. DaggerAppComponent @Generated public final class DaggerAppComponent implements AppComponent { private Provider<SomeDependency> someDependencyProvider; /** other code **/ private void initialize(final Builder builder) { this.someDependencyProvider = AppModule_SomeDependencyFactory.create(builder.appModule); } } (Generated)
39. @ragdroid @droidconDE CASE 2 DEPENDENCY WITH SCOPE
40. AppModule @Module public class AppModule { @Provides @Singleton SomeDependency applicationProvider() { return new SomeDependency; } }
41. AppModule @Module public class AppModule { @Provides @Singleton SomeDependency applicationProvider() { return new SomeDependency; } }
42. DaggerAppComponent @Generated public final class DaggerAppComponent implements AppComponent { private Provider<SomeDependency> someDependencyProvider; /** other code **/ private void initialize(final Builder builder) { this.someDependencyProvider = DoubleCheck.provider( AppModule_SomeDependencyFactory.create(builder.appModule)); } } (Generated)
43. DaggerAppComponent (Generated) @Generated public final class DaggerAppComponent implements AppComponent { private Provider<SomeDependency> someDependencyProvider; /** other code **/ private void initialize(final Builder builder) { this.someDependencyProvider = DoubleCheck.provider( AppModule_SomeDependencyFactory.create(builder.appModule)); } }
44. DaggerAppComponent (Generated) @Generated public final class DaggerAppComponent implements AppComponent { private Provider<SomeDependency> someDependencyProvider; /** other code **/ private void initialize(final Builder builder) { this.someDependencyProvider = DoubleCheck.provider( AppModule_SomeDependencyFactory.create(builder.appModule)); } }
45. DoubleCheck Memoizes value using Double-Check idiom. (dagger.internal)
46. DoubleCheck Memoizes value using Double-Check idiom. public T get() {
 Object result = instance;
 if (result == UNINITIALIZED) {
 synchronized (this) {
 result = instance;
 if (result == UNINITIALIZED) {
 result = provider.get();
 
 Object currentInstance = instance; // other code
 instance = result;
 
 provider = null;
 }
 }
 }
 return (T) result;
 } (dagger.internal)
47. DoubleCheck Memoizes value using Double-Check idiom. public T get() {
 Object result = instance;
 if (result == UNINITIALIZED) {
 synchronized (this) {
 result = instance;
 if (result == UNINITIALIZED) {
 result = provider.get();
 
 Object currentInstance = instance; // other code
 instance = result;
 
 provider = null;
 }
 }
 }
 return (T) result;
 } (dagger.internal)
48. DoubleCheck Memoizes value using Double-Check idiom. public T get() {
 Object result = instance;
 if (result == UNINITIALIZED) {
 synchronized (this) {
 result = instance;
 if (result == UNINITIALIZED) {
 result = provider.get();
 
 Object currentInstance = instance; // other code
 instance = result;
 
 provider = null;
 }
 }
 }
 return (T) result;
 } (dagger.internal)
49. Take Aways • DONT “Scope All the Things!” • Scoping has overheads. • By-default no Scope. • Scope only when needed • Like for Heavy Mutable Objects
50. @ragdroid @droidconDE @REUSABLE
51. @Reusable • Limit the instantiation. • Use when Exact same instance not needed. • Not tied to any component or subcomponent. • Can Have multiple sub-components caching different instances. • Use for heavy immutable dependencies.
52. ReusableComponent 
 @Component(modules = ReusableModule.class) public interface ReusableComponent { SomeObject someObject(); }
53. ReusableComponent 
 @Component(modules = ReusableModule.class) public interface ReusableComponent { SomeObject someObject(); }
54. SomeObject @Reusable public class SomeObject { @Inject public SomeObject() { } }
55. DaggerReusableComponent @Generated public final class DaggerReusableComponent implements ReusableComponent { /** other code **/ Provider<SomeObject> someObjectProvider; private void initialize(final Builder builder) { this.someObjectProvider = SingleCheck.provider(SomeObject_Factory.create()); } } (Generated)
56. DaggerReusableComponent @Generated public final class DaggerReusableComponent implements ReusableComponent { /** other code **/ Provider<SomeObject> someObjectProvider; private void initialize(final Builder builder) { this.someObjectProvider = SingleCheck.provider(SomeObject_Factory.create()); } } (Generated)
57. DaggerReusableComponent @Generated public final class DaggerReusableComponent implements ReusableComponent { /** other code **/ Provider<SomeObject> someObjectProvider; private void initialize(final Builder builder) { this.someObjectProvider = SingleCheck.provider(SomeObject_Factory.create()); } } (Generated)
58. SingleCheck Memoizes value using simple lazy initialization and caching (dagger.internal)
59. Memoizes value using simple lazy initialization and caching public T get() {
 
 Provider<T> providerReference = provider;
 if (instance == UNINITIALIZED) {
 instance = providerReference.get();
 provider = null;
 }
 return (T) instance;
 } (dagger.internal) SingleCheck
60. Memoizes value using simple lazy initialization and caching public T get() {
 
 Provider<T> providerReference = provider;
 if (instance == UNINITIALIZED) {
 instance = providerReference.get();
 provider = null;
 }
 return (T) instance;
 } (dagger.internal) SingleCheck
61. No Scope vs @Singleton vs @Reusable • Not Heavy : No Scope • Heavy mutable object : @Singleton • Heavy immutable object : @Reusable •
62. @ragdroid @droidconDE GOD APP MODULE
63. @ragdroid @droidconDE App Module AppComponent @Module public class AppModule { private final Application application; @Provides @Si AppModule @Singleton @Component(modules = AppModule.class) @Singleton public interface AppComponent { Application application(); }
64. @ragdroid @droidconDE Big App Module AppComponent @Module public class AppModule { private final Application application; @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton AppModule @Singleton @Component(modules = AppModule.class) @Singleton public interface AppComponent { Application application(); }
65. @ragdroid @droidconDE AppComponent @Module public class AppModule { private final Application application; @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } } AppModule @Singleton Big App Module @Component(modules = AppModule.class) @Singleton public interface AppComponent { Application application(); }
66. @ragdroid @droidconDE AppComponent @Module public class AppModule { private final Application application; @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } } AppModule @Singleton God Module God App Module @Component(modules = AppModule.class) @Singleton public interface AppComponent { Application application(); }
67. @ragdroid @droidconDE God App Module How To Improve?
68. @ragdroid @droidconDE God App Module Splitting App Module
69. @ragdroid @droidconDE AppComponent @Module public class AppModule { private final Application application; @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } } @Singleton @Component(modules = AppModule.class) @Singleton public interface AppComponent { Application application(); } Splitting App Module ApiModule AppModule
70. @ragdroid @droidconDE Splitting App Module @Module public class AppModule { private final Application application; @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } } AppModule ApiModule AppComponent @Singleton @Component(modules = AppModule.class) @Singleton public interface AppComponent { Application application(); }
71. @ragdroid @droidconDE Splitting App Module AppComponent @Module public class AppModule { private final Application application; @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } } AppModule @Singleton @Component(modules = AppModule.class) @Singleton public interface AppComponent { Application application(); } ApiModule @Component( modules = AppModule.class, ApiModule.class)
72. @ragdroid @droidconDE Splitting App Module @Module public class AppModule { private final Application application; @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } } AppModule ApiModule @Component( modules = AppModule.class, ApiModule.class) OR AppComponent
73. @ragdroid @droidconDE Splitting App Module @Module public class AppModule { private final Application application; @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } @Provides @Singleton Application applicationProvider() { return application; } } AppModule ApiModule @Component( modules = AppModule.class, ApiModule.class) @Module( includes = ApiModule.class) AppModule OR AppComponent
74. @ragdroid @droidconDE Splitting App Module
75. @ragdroid @droidconDE How to Improve? • Better Scope Management • More modularity • Custom Scopes : • @UserScope • @ActivityScope • @FragmentScope
76. @ragdroid @droidconDE Custom Scopes
77. @ragdroid @droidconDE Custom Scopes Multiple Components
78. Multiple Components 1. Dependent Components 2. Sub-Components
79. COMPONENT DEPENDENCIES
80. @ragdroid @droidconDE POKEMON APP
81. AppComponent (@Singleton) UserComponent (@UserScope) UserComponent @UserScope Login Component @ActivityScope Home Component Items Component Login Component Home Component Items Component Fragments Fragments Application
82. AppComponent (@Singleton) UserComponent (@UserScope) UserComponent @UserScope Login Component @ActivityScope Home Component Items Component Login Component Home Component Items Component Fragments Fragments Launch Application
83. AppComponent (@Singleton) UserComponent (@UserScope) UserComponent @UserScope Login Component @ActivityScope Home Component Items Component Login Component Home Component Items Component Fragments Fragments Launch pikachu Login Application
84. AppComponent (@Singleton) UserComponent (@UserScope) UserComponent @UserScope Login Component @ActivityScope Home Component Items Component Login Component Home Component Items Component Fragments Fragments Launch pikachu Login Inventory Application
85. AppComponent (@Singleton) UserComponent (@UserScope) UserComponent @UserScope Login Component @ActivityScope Home Component Items Component Login Component Home Component Items Component Fragments Fragments Launch pikachu Login Log-Out Inventory Application
86. AppComponent (@Singleton) UserComponent (@UserScope) UserComponent @UserScope Login Component @ActivityScope Home Component Items Component Login Component Home Component Items Component Fragments Fragments Launch pikachu Login Log-Out jigglypuff Inventory Application
87. AppComponent (@Singleton) UserComponent (@UserScope) UserComponent @UserScope Login Component @ActivityScope Home Component Items Component Login Component Home Component Items Component Fragments Fragments Launch pikachu Login Log-Out jigglypuff Inventory Inventory Application
88. Pokemon App
89. @ragdroid @droidconDE SUB COMPONENT VS DEPENDENT COMPONENT
90. <<interface>> AppComponent schedulerProvider @Singleton
91. AppComponentImpl • schedulerProvider() : @Singleton • userManager : @Singleton LoginComponentImpl <<interface>> AppComponent schedulerProvider Login Sub Component @Singleton @ActivityScope
92. UserComponentImpl • schedulerProvider • pokemon AppComponentImpl • schedulerProvider() : @Singleton • userManager : @Singleton LoginComponentImpl <<interface>> AppComponent schedulerProvider HomeComponentImpl ItemsComponentImpl @Singleton @ActivityScope @UserScope @ActivityScope @ActivityScope Login Sub Component User Dependent Component
93. UserComponentImpl • schedulerProvider • pokemon AppComponentImpl • schedulerProvider() : @Singleton • userManager : @Singleton LoginComponentImpl <<interface>> AppComponent schedulerProvider HomeComponentImpl ItemsComponentImpl User Dependent Component @Singleton @ActivityScope @UserScope @ActivityScope @ActivityScope Login Sub Component
94. @ragdroid @droidconDE APP COMPONENT
95. @Singleton @Component(modules = arrayOf(AppModule::class, ApiModule::class)) interface AppComponent { fun loginBuilder(): LoginComponent.Builder fun schedulerProvider(): BaseSchedulerProvider } AppComponent
96. @Singleton @Component(modules = arrayOf(AppModule::class, ApiModule::class)) interface AppComponent { fun loginBuilder(): LoginComponent.Builder fun schedulerProvider(): BaseSchedulerProvider } AppComponent
97. @Singleton @Component(modules = arrayOf(AppModule::class, ApiModule::class)) interface AppComponent { fun loginBuilder(): LoginComponent.Builder fun schedulerProvider(): BaseSchedulerProvider } AppComponent
98. @ragdroid @droidconDE DAHAKA APPLICATION
99. class DahakaApplication : Application() { override fun onCreate() { super.onCreate() appComponent = DaggerAppComponent .builder() .application(this) .build() } } DahakaApplication
100. class DahakaApplication : Application() { override fun onCreate() { super.onCreate() appComponent = DaggerAppComponent .builder() .application(this) .build() } } DahakaApplication
101. DEPENDENT COMPONENTS
102. @ragdroid @droidconDE USER COMPONENT
103. @Component(dependencies = arrayOf(AppComponent::class), modules = arrayOf(UserModule::class)) @UserScope interface UserComponent { @Component.Builder interface Builder { @BindsInstance fun pokeMon(pokemon: Pokemon): Builder … } } UserComponent
104. @Component(dependencies = arrayOf(AppComponent::class), modules = arrayOf(UserModule::class)) @UserScope interface UserComponent { @Component.Builder interface Builder { @BindsInstance fun pokeMon(pokemon: Pokemon): Builder … } } UserComponent
105. @Component(dependencies = arrayOf(AppComponent::class), modules = arrayOf(UserModule::class)) @UserScope interface UserComponent { @Component.Builder interface Builder { @BindsInstance fun pokeMon(pokemon: Pokemon): Builder … } } UserComponent
106. Binding Pokemon • Two ways of Providing / Binding Pokemon to graph 1. UserModule Constructor 2. @Component.Builder with @BindsInstance
107. 
 @Module
 public abstract class UserModule {
 
 private final Pokemon pokemon;
 
 public UserModule(Pokemon pokemon) {
 this.pokemon = pokemon;
 }
 
 @Provides
 @UserScope
 public Pokemon providePokemon() {
 return pokemon;
 }
 
 }
 UserModule Constructor
108. 
 @Module
 public abstract class UserModule {
 
 private final Pokemon pokemon;
 
 public UserModule(Pokemon pokemon) {
 this.pokemon = pokemon;
 }
 
 @Provides
 @UserScope
 public Pokemon providePokemon() {
 return pokemon;
 }
 
 }
 UserModule Constructor
109. 
 @Module
 public abstract class UserModule {
 
 private final Pokemon pokemon;
 
 public UserModule(Pokemon pokemon) {
 this.pokemon = pokemon;
 }
 
 @Provides
 @UserScope
 public Pokemon providePokemon() {
 return pokemon;
 }
 
 }
 UserModule Constructor
110. @Component(dependencies = arrayOf(AppComponent::class), modules = arrayOf(UserModule::class)) @UserScope interface UserComponent { @Component.Builder interface Builder { @BindsInstance fun pokeMon(pokemon: Pokemon): Builder … } } User Component @Component.Builder
111. @Component(dependencies = arrayOf(AppComponent::class), modules = arrayOf(UserModule::class)) @UserScope interface UserComponent { @Component.Builder interface Builder { @BindsInstance fun pokeMon(pokemon: Pokemon): Builder … } } UserComponent @BindsInstance
112. @ragdroid @droidconDE USER MANAGER
113. @Singleton class UserManager @Inject constructor(private val service: PokemonService) { var userComponent: UserComponent? = null private set public fun createUserSession(pokemon: Pokemon) { userComponent = DaggerUserComponent.builder() .appComponent(DahakaApplication.app.appComponent) .pokeMon(pokemon) .build() } … } UserManager
114. @Singleton class UserManager @Inject constructor(private val service: PokemonService) { var userComponent: UserComponent? = null private set public fun createUserSession(pokemon: Pokemon) { userComponent = DaggerUserComponent.builder() .appComponent(DahakaApplication.app.appComponent) .pokeMon(pokemon) .build() } … } UserManager
115. @Singleton class UserManager @Inject constructor(private val service: PokemonService) { var userComponent: UserComponent? = null private set public fun createUserSession(pokemon: Pokemon) { userComponent = DaggerUserComponent.builder() .appComponent(DahakaApplication.app.appComponent) .pokeMon(pokemon) .build() } … } UserManager
116. @ragdroid @droidconDE DAGGER USER COMPONENT (Generated)
117. public final class DaggerUserComponent implements UserComponent { private Provider<BaseSchedulerProvider> schedulerProvider; private void initialize(final Builder builder) { this.schedulerProvider = new AppComponent_schedulerProvider(builder.appComponent); … } private static class AppComponent_schedulerProvider implements Provider<BaseSchedulerProvider> { private final AppComponent appComponent; @Override public BaseSchedulerProvider get() { return appComponent.schedulerProvider(); } … } } DaggerUserComponent (Generated)
118. public final class DaggerUserComponent implements UserComponent { private Provider<BaseSchedulerProvider> schedulerProvider; private void initialize(final Builder builder) { this.schedulerProvider = new AppComponent_schedulerProvider(builder.appComponent); … } private static class AppComponent_schedulerProvider implements Provider<BaseSchedulerProvider> { private final AppComponent appComponent; @Override public BaseSchedulerProvider get() { return appComponent.schedulerProvider(); } … } } DaggerUserComponent (Generated)
119. public final class DaggerUserComponent implements UserComponent { private Provider<BaseSchedulerProvider> schedulerProvider; private void initialize(final Builder builder) { this.schedulerProvider = new AppComponent_schedulerProvider(builder.appComponent); … } private static class AppComponent_schedulerProvider implements Provider<BaseSchedulerProvider> { private final AppComponent appComponent; @Override public BaseSchedulerProvider get() { return appComponent.schedulerProvider(); } … } } DaggerUserComponent (Generated)
120. public final class DaggerUserComponent implements UserComponent { private Provider<BaseSchedulerProvider> schedulerProvider; private void initialize(final Builder builder) { this.schedulerProvider = new AppComponent_schedulerProvider(builder.appComponent); … } private static class AppComponent_schedulerProvider implements Provider<BaseSchedulerProvider> { private final AppComponent appComponent; @Override public BaseSchedulerProvider get() { return appComponent.schedulerProvider(); } … } } DaggerUserComponent (Generated)
121. public final class DaggerUserComponent implements UserComponent { private Provider<BaseSchedulerProvider> schedulerProvider; private void initialize(final Builder builder) { this.schedulerProvider = new AppComponent_schedulerProvider(builder.appComponent); … } private static class AppComponent_schedulerProvider implements Provider<BaseSchedulerProvider> { private final AppComponent appComponent; @Override public BaseSchedulerProvider get() { return appComponent.schedulerProvider(); } … } } DaggerUserComponent (Generated)
122. public final class DaggerUserComponent implements UserComponent { private Provider<BaseSchedulerProvider> schedulerProvider; private void initialize(final Builder builder) { this.schedulerProvider = new AppComponent_schedulerProvider(builder.appComponent); … } private static class AppComponent_schedulerProvider implements Provider<BaseSchedulerProvider> { private final AppComponent appComponent; @Override public BaseSchedulerProvider get() { return appComponent.schedulerProvider(); } … } } DaggerUserComponent (Generated)
123. SUB COMPONENTS
124. @ragdroid @droidconDE LOGIN SUBCOMPONENT
125. @ActivityScope @Subcomponent(modules = arrayOf(LoginModule::class)) interface LoginComponent { @Subcomponent.Builder interface Builder { @BindsInstance fun loginActivity(loginActivity: LoginActivity): Builder } } LoginComponent
126. @ActivityScope @Subcomponent(modules = arrayOf(LoginModule::class)) interface LoginComponent { @Subcomponent.Builder interface Builder { @BindsInstance fun loginActivity(loginActivity: LoginActivity): Builder } } LoginComponent
127. @ActivityScope @Subcomponent(modules = arrayOf(LoginModule::class)) interface LoginComponent { @Subcomponent.Builder interface Builder { @BindsInstance fun loginActivity(loginActivity: LoginActivity): Builder } } LoginComponent
128. @ActivityScope @Subcomponent(modules = arrayOf(LoginModule::class)) interface LoginComponent { @Subcomponent.Builder interface Builder { @BindsInstance fun loginActivity(loginActivity: LoginActivity): Builder } } LoginComponent
129. @ActivityScope @Subcomponent(modules = arrayOf(LoginModule::class)) interface LoginComponent { @Subcomponent.Builder interface Builder { @BindsInstance fun loginActivity(loginActivity: LoginActivity): Builder } } LoginComponent
130. @ragdroid @droidconDE LOGIN ACTIVITY
131. class LoginActivity { private lateinit var loginComponent: LoginComponent override fun initDagger(appComponent: AppComponent) { loginComponent = appComponent .loginBuilder() .loginActivity(this) .build() } … } LoginActivity
132. class LoginActivity { private lateinit var loginComponent: LoginComponent override fun initDagger(appComponent: AppComponent) { loginComponent = appComponent .loginBuilder() .loginActivity(this) .build() } … } LoginActivity
133. @ragdroid @droidconDE DAGGER APP COMPONENT (Generated)
134. public final class DaggerAppComponent implements AppComponent { private final class LoginComponentImpl implements LoginComponent { private LoginComponentImpl(LoginComponentBuilder builder) { assert builder != null; initialize(builder); } … } } DaggerAppComponent (Generated)
135. public final class DaggerAppComponent implements AppComponent { private final class LoginComponentImpl implements LoginComponent { private LoginComponentImpl(LoginComponentBuilder builder) { assert builder != null; initialize(builder); } … } } DaggerAppComponent (Generated)
136. public final class DaggerAppComponent implements AppComponent { private final class LoginComponentImpl implements LoginComponent { private LoginComponentImpl(LoginComponentBuilder builder) { assert builder != null; initialize(builder); } … } } DaggerAppComponent (Generated)
137. @ragdroid @droidconDE SUB COMPONENT VS DEPENDENT COMPONENT
138. <<interface>> AppComponent fun schedulerProvider() @Singleton
139. DaggerAppComponent • schedulerProvider() : @Singleton • userManager : @Singleton LoginComponentImpl <<interface>> AppComponent fun schedulerProvider() @Singleton @ActivityScope
140. DaggerAppComponent • schedulerProvider() : @Singleton • userManager : @Singleton LoginComponentImpl <<interface>> AppComponent fun schedulerProvider() Sub Component LoginComponent accesses any dependencies of DaggerAppComponent directly as inner class can access outer class members. @Singleton @ActivityScope
141. DaggerUserComponent • schedulerProvider • pokemon DaggerAppComponent • schedulerProvider() : @Singleton • userManager : @Singleton LoginComponentImpl <<interface>> AppComponent fun schedulerProvider() HomeComponentImpl ItemsComponentImpl Dependent Component UserComponent accesses any dependencies of DaggerAppComponent via an interface of AppComponent. @Singleton @ActivityScope @UserScope @ActivityScope @ActivityScope Sub Component LoginComponent accesses any dependencies of DaggerAppComponent directly as inner class can access outer class members.
142. DaggerUserComponent • schedulerProvider • pokemon DaggerAppComponent • schedulerProvider() : @Singleton • userManager : @Singleton LoginComponentImpl <<interface>> AppComponent fun schedulerProvider() HomeComponentImpl ItemsComponentImpl @Singleton @ActivityScope @UserScope @ActivityScope @ActivityScope Sub Component LoginComponent accesses any dependencies of DaggerAppComponent directly as inner class can access outer class members. Dependent Component UserComponent accesses any dependencies of DaggerAppComponent via an interface of AppComponent.
143. @ragdroid @droidconDE Custom Scope Advantages • Dependency Lifecycle Management • Modularized code
144. @ragdroid @droidconDE Some Limitations • Repetitive Injection code • Class knows about it’s Injector
145. @ragdroid @droidconDE Some Limitations Dagger 2 Android
146. INTERMEDIATE CONCEPTS “DEFEAT THE DAHAKA”
147. @ragdroid @droidconDE @BINDS
148. @Module public class AppModule { @Provides BaseSchedulerProvider providerSchedulerProvider(SchedulerProvider provider) { return provider; } } @Binds
149. @Module public class AppModule { @Provides BaseSchedulerProvider providerSchedulerProvider(SchedulerProvider provider) { return provider; } } @Binds @Module public abstract class AppModule { @Binds abstract BaseSchedulerProvider providerSchedulerProvider(SchedulerProvider provider); }
150. @ragdroid @droidconDE MULTIBINDING
151. MultiBinding @IntoSet @Provides String - “Hello” @Provides String - “Hi” @Provides String - “How are you?”
152. @Provides String - “Hello” @Provides String - “Hi” @Provides String - “How are you?” @IntoSet @IntoSet @IntoSet MultiBinding @IntoSet
153. @Provides Set<String> {“Hello”, “Hi”, “How are you?”} MultiBinding @IntoSet
154. MultiBinding @IntoMap <<interface>> Contract.Presenter MapPresenter JustPresenter TakePresenter
155. MultiBinding @IntoMap @Provides MapPresenter mapPresenter @Provides JustPresenter justPresenter @Provides TakePresenter takePresenter
156. MultiBinding @IntoMap @Provides MapPresenter mapPresenter @Provides JustPresenter justPresenter @Provides TakePresenter takePresenter @IntoMap @IntoMap @IntoMap
157. MultiBinding @IntoMap @Provides MapPresenter mapPresenter @Provides JustPresenter justPresenter @Provides TakePresenter takePresenter @IntoMap @IntoMap @IntoMap @ClassKey(MapPresenter.java) @ClassKey(JustPresenter.java) @ClassKey(TakePresenter.java)
158. MultiBinding @IntoMap @Provides Map<Class, Contract.Presenter> { mapPresenter, justPresenter, takePresenter }
159. DAGGER 2 ANDROID “BEFRIEND THE BEAST”
160. @ragdroid @droidconDE DAHAKA APPLICATION
161. class DahakaApplication : Application(), HasActivityInjector { @Inject internal lateinit var activityInjector: DispatchingAndroidInjector<Activity> … override fun activityInjector(): AndroidInjector<Activity> { return activityInjector } … } DahakaApplication
162. class DahakaApplication : Application(), HasActivityInjector { @Inject internal lateinit var activityInjector: DispatchingAndroidInjector<Activity> … override fun activityInjector(): AndroidInjector<Activity> { return activityInjector } … } DahakaApplication
163. class DahakaApplication : Application(), HasActivityInjector { @Inject internal lateinit var activityInjector: DispatchingAndroidInjector<Activity> … override fun activityInjector(): AndroidInjector<Activity> { return activityInjector } … } DahakaApplication
164. class DahakaApplication : Application(), HasActivityInjector { @Inject internal lateinit var activityInjector: DispatchingAndroidInjector<Activity> … override fun activityInjector(): AndroidInjector<Activity> { return activityInjector } … } DahakaApplication
165. public interface HasActivityInjector { AndroidInjector<Activity> activityInjector(); } HasActivityInjector
166. HasActivityInjector • A simple interface. • Implementing class “Has” ActivityInjector. public interface HasActivityInjector { AndroidInjector<Activity> activityInjector(); }
167. DispatchingAndroidInjector : AndroidInjector
168. DispatchingAndroidInjector : AndroidInjector • Injects members for Android types : Activity, Fragment, etc • Has a Map<Class, Provider<Factory>> injectorFactories.
169. Provider<LoginActivitySubcomponent.Builder> LoginActivity.class Class<Activity> Provider<Factory<Activity>> DispatchingAndroidInject<Activity> • gets the Subcomponent.Builder from Map. • creates an instance using Builder. • calls component.inject(instance) to perform injections. • Injects members for Android types : Activity, Fragment, etc • Has a Map<Class, Provider<Factory>> injectorFactories. DispatchingAndroidInjector : AndroidInjector
170. @ragdroid @droidconDE APP COMPONENT
171. @Singleton @Component(modules = arrayOf(AppModule::class, ApiModule::class, AppBindingModule::class, AndroidSupportInjectionModule::class)) interface AppComponent : AndroidInjector<DaggerApplication> { … } AppComponent
172. AppBindingModule @Singleton @Component(modules = arrayOf(AppModule::class, ApiModule::class, AppBindingModule::class, AndroidSupportInjectionModule::class)) interface AppComponent : AndroidInjector<DaggerApplication> { … } AppComponent
173. @Module abstract class AppBindingModule { @ContributesAndroidInjector(modules = arrayOf(LoginModule::class)) @ActivityScope internal abstract fun loginActivity(): LoginActivity } AppBindingModule
174. @ContributesAndroidInjector @Module abstract class AppBindingModule { @ContributesAndroidInjector(modules = arrayOf(LoginModule::class)) @ActivityScope internal abstract fun loginActivity(): LoginActivity } AppBindingModule
175. @Module abstract class AppBindingModule { @ContributesAndroidInjector(modules = arrayOf(LoginModule::class)) @ActivityScope internal abstract fun loginActivity(): LoginActivity } AppBindingModule • If your Module is stateless. • If your Subcomponent.Builder is simple and doesn’t need to bind anything extra. • @ContributesAndroidInjector will generate the SubComponent for you. • No need to create LoginActivitySubcomponent class in the above case. @ContributesAndroidInjector AppBindingModule
176. @Module abstract class AppBindingModule { @ContributesAndroidInjector(modules = arrayOf(LoginModule::class)) @ActivityScope internal abstract fun loginActivity(): LoginActivity } AppBindingModule @Module abstract class LoginModule { @Binds abstract fun provideLoginPresenter(loginPresenter: LoginPresenter): LoginContract.Presenter } LoginModule
177. @Module(subcomponents = LoginActivitySubcomponent.class) public abstract class AppBindingModule_LoginActivity { @Binds @IntoMap @ActivityKey(LoginActivity.class) abstract AndroidInjector.Factory<? extends Activity> bindAndroidInjectorFactory( LoginActivitySubcomponent.Builder builder); @Subcomponent(modules = LoginModule.class) @ActivityScope public interface LoginActivitySubcomponent extends AndroidInjector<LoginActivity> { @Subcomponent.Builder abstract class Builder extends AndroidInjector.Builder<LoginActivity> {} } } LoginBindingModule(Generated)
178. @Module(subcomponents = LoginActivitySubcomponent.class) public abstract class AppBindingModule_LoginActivity { @Binds @IntoMap @ActivityKey(LoginActivity.class) abstract AndroidInjector.Factory<? extends Activity> bindAndroidInjectorFactory( LoginActivitySubcomponent.Builder builder); @Subcomponent(modules = LoginModule.class) @ActivityScope public interface LoginActivitySubcomponent extends AndroidInjector<LoginActivity> { @Subcomponent.Builder abstract class Builder extends AndroidInjector.Builder<LoginActivity> {} } } LoginBindingModule(Generated)
179. @Module(subcomponents = LoginActivitySubcomponent.class) public abstract class AppBindingModule_LoginActivity { @Binds @IntoMap @ActivityKey(LoginActivity.class) abstract AndroidInjector.Factory<? extends Activity> bindAndroidInjectorFactory( LoginActivitySubcomponent.Builder builder); @Subcomponent(modules = LoginModule.class) @ActivityScope public interface LoginActivitySubcomponent extends AndroidInjector<LoginActivity> { @Subcomponent.Builder abstract class Builder extends AndroidInjector.Builder<LoginActivity> {} } } LoginBindingModule(Generated)
180. @Module(subcomponents = LoginActivitySubcomponent.class) public abstract class AppBindingModule_LoginActivity { @Binds @IntoMap @ActivityKey(LoginActivity.class) abstract AndroidInjector.Factory<? extends Activity> bindAndroidInjectorFactory( LoginActivitySubcomponent.Builder builder); @Subcomponent(modules = LoginModule.class) @ActivityScope public interface LoginActivitySubcomponent extends AndroidInjector<LoginActivity> { @Subcomponent.Builder abstract class Builder extends AndroidInjector.Builder<LoginActivity> {} } } LoginBindingModule(Generated)
181. @ragdroid @droidconDE LOGIN ACTIVITY
182. public class LoginActivity { @Inject LoginContract.Presenter presenter; @Override protected void onCreate(Bundle savedInstanceState) { AndroidInjection.inject(this); } } LoginActivity
183. AndroidInjection.inject(LoginActivity) LoginActivity public class LoginActivity { @Inject LoginContract.Presenter presenter; @Override protected void onCreate(Bundle savedInstanceState) { AndroidInjection.inject(this); } }
184. AndroidInjection.inject(LoginActivity) AndroidInjection.inje
185. AndroidInjection.inject(LoginActivity) AndroidInjection.inje AndroidInjection
186. AndroidInjection.inject(LoginActivity) AndroidInjection.inje AndroidInjection DaggerAppComponent
187. AndroidInjection.inject(LoginActivity) AndroidInjection.inje AndroidInjection DaggerAppComponent AppBindingModule_LoginActivity DispatchingAndroidInjector
188. AndroidInjection.inject(LoginActivity) AndroidInjection.inje AndroidInjection DaggerAppComponent AppBindingModule_LoginActivity DispatchingAndroidInjector
189. AndroidInjection.inject(LoginActivity) AndroidInjection.inje AndroidInjection DaggerAppComponent AppBindingModule_LoginActivity DispatchingAndroidInjector ApiModule_ProvideRetrofitFactory AppModule_ProviderSchedulerProviderFactory ApiModule_ProvidePokemonServiceFactory ApiModule_ProvideRetrofitFactory AppModule_ProviderSchedulerProviderFactory ApiModule_ProvidePokemonServiceFactory
190. @ragdroid @droidconDE BEFRIEND THE BEAST “You can not change your fate, No droid can.”
191. AndroidInjection.inject(LoginActivity)
192. AndroidInjection.inject(LoginActivity) activity .getApplication() LoginActivity
193. AndroidInjection.inject(LoginActivity) activity .getApplication() LoginActivity application .activityInjector() DahakaApplication : HasActivityInjector
194. AndroidInjection.inject(LoginActivity) activity .getApplication() LoginActivity application .activityInjector() DahakaApplication : HasActivityInjector activityInjector .inject(activity) DispatchingAndroidInjector : AndroidInjector
195. AndroidInjection.inject(LoginActivity) activity .getApplication() LoginActivity application .activityInjector() DahakaApplication : HasActivityInjector activityInjector .inject(activity) DispatchingAndroidInjector : AndroidInjector
196. DispatchingAndroidInjector.inject(LoginActivity) injectorFactories .get(LoginActivity.class) DispatchingAndroidInjector : AndroidInjector
197. DispatchingAndroidInjector : AndroidInjector Factory<LoginActivity> : LoginSubcomponent.Builder injectorFactories .get(LoginActivity.class) DispatchingAndroidInjector.inject(LoginActivity) builder .build()
198. DispatchingAndroidInjector : AndroidInjector Factory<LoginActivity> : LoginSubcomponent.Builder component .inject(activity) LoginSubcomponent injectorFactories .get(LoginActivity.class) DispatchingAndroidInjector.inject(LoginActivity) builder .build()
199. DispatchingAndroidInjector : AndroidInjector builder .build() Factory<LoginActivity> : LoginSubcomponent.Builder component .inject(activity) LoginSubcomponent DispatchingAndroidInjector.inject(LoginActivity) injectorFactories .get(LoginActivity.class)
200. • DaggerApplication • DaggerActivity • DaggerBroadcastReceiver • DaggerContentProvider • DaggerFragment • DaggerIntentService • DaggerService Dagger Boilerplate classes
201. Demo Code • Dahaka Demo : https://github.com/ragdroid/Dahaka • Branches : • dagger-android : Pokemon app using dagger-android (With Tests, Fragments) • dagger-android-dependent-comp : dagger-android with Dependent Component • dagger-android-dependent-comp-kotlin : In Kotlin • subcomponent : UserComponent as subcomponent • dependent-component : UserComponent as dependent component • dependent-component-kotlin : In Kotlin
202. @ragdroid @droidconDE Dagger 2 Android = Dahaka • D • A • H • A • K • A Dagger Android HasActivityInjector AndroidInjection Keys AndroidInjector
203. @ragdroid @droidconDE Dagger 2 Android “You can not change your fate, No droid can” Let’s befriend the beast instead.
204. Acknowledgements • Dagger Recipies : Miroslaw Stanek (@froger_mcs) https://about.me/froger_mcs • todo-mvp-dagger : Mike Nakhimovich (@friendlyMikhail ) https://github.com/googlesamples/android-architecture/tree/todo-mvp-dagger • Android Dialogs : Mike Nakhimovich https://www.youtube.com/watch?v=KwRXQ6nT7jQ • Proof Reading : Ritesh Gupta (@_riteshhh) • Migrate to Kotlin : Ravindra Kumar (@ravidsrk)
205. What Next? • Dagger Documentation : https://google.github.io/dagger// • todo-mvp-dagger : Mike Nakhimovich (@friendlyMikhail ) https://github.com/googlesamples/android-architecture/tree/todo-mvp-dagger • Dagger Example https://github.com/ragdroid/Dahaka • Testing article https://android.jlelse.eu/testing-your-app-with-dagger-2-c91cdc0860fb • Dagger and the Dahaka Series : https://medium.com/@ragdroid
206. Other References • Theme : Prince of Persia https://en.wikipedia.org/wiki/Prince_of_Persia • Dahaka https://files.gamebanana.com/img/ico/sprays/dahaka.png • Dagger https://in.pinterest.com/pin/397442735844321339/ • Android http://www.pngmart.com/files/4/Android-PNG-Image.png
207. @ragdroid @droidconDE CUT SCENES
208. Dagger 2 Android “Defeat the Dahaka" Garima Jain @ragdroid
209. Dagger 2 Android “Defeat the Dahaka" Garima Jain @ragdroid
210. FUELED http://fueled.com/garima garima@fueled.com THANK YOU
211. FUELED http://fueled.com/garima garima@fueled.com Q & A @ragdroid