Dagger Party Tricks

Neat things you can do with dagger and common libraries/patterns in modern android development.

Given at Londroid on 2019/02/19 and Droidcon NYC on 2019/08/26

Transcript

1. Dagger Party Tricks @ZacSweers
2. Dagger?
3. Dagger Party Tricks
4. 4ish Dagger Party Tricks
5. Deferred Initialization
9. @Provides fun provideRetrofit(): Retrofit { return Retrofit.Builder() .baseUrl("https://example.com") .build() }a
10. @Provides fun provideClient(): OkHttpClient { return OkHttpClient.Builder() .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a
11. @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a
12. @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a
13. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a @Inject constructor( retrofit: Retrofit )e
14. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a @Inject constructor( retrofit: Retrofit )e
15. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a @Inject constructor( retrofit: Retrofit )e
16. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a @Inject constructor( retrofit: Retrofit )e
17. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a 100-150ms! @Inject constructor( retrofit: Retrofit )e
18. Lazy!
19. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a 100-150ms! @Inject constructor( retrofit: Retrofit )e
20. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a @Inject constructor( retrofit: Lazy<Retrofit> )e 100-150ms!
21. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a @Inject constructor( retrofit: Lazy<Retrofit> )e 100-150ms! retrofit.get().create(...)
22. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a @Inject constructor( retrofit: Lazy<Retrofit> )e 100-150ms! retrofit.get().create(...)
23. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a
24. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .callFactory(client) .build() }a
25. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .callFactory(client) .build() }a Call.Factory
26. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .callFactory(object : Call.Factory by client {}) .build() }a
27. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .callFactory { client.newCall(it) } .build() }a
28. @Provides fun provideRetrofit(client: Lazy<OkHttpClient>): Retrofit { return Retrofit.Builder() .callFactory { client.get().newCall(it) } .build() }a
29. @Provides fun provideRetrofit(client: Lazy<OkHttpClient>): Retrofit { return Retrofit.Builder() .callFactory { client.get().newCall(it) } .build() }a
30. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a @Inject constructor( retrofit: Lazy<Retrofit> )e 100-150ms! retrofit.get().create(...)
31. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit(client: OkHttpClient): Retrofit { return Retrofit.Builder() .client(client) .build() }a @Inject constructor( retrofit: Lazy<Retrofit> )e 100-150ms! retrofit.get().create(...) Main thread!
32. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit( client: Lazy<OkHttpClient>): Retrofit { return Retrofit.Builder() .callFactory { client.get().newCall(it) } .build() }a @Inject constructor( retrofit: Retrofit )e 100-150ms! Background thread
33. Courtesy of Nick Butcher (@crafty) @Provides fun provideCache(ctx: Context): Cache { checkMainThread() return Cache(ctx.cacheDir, CACHE_SIZE) }c @Provides fun provideClient(cache: Cache): OkHttpClient { checkMainThread() return OkHttpClient.Builder() .cache(cache) .build() }b @Provides fun provideRetrofit( client: Lazy<OkHttpClient>): Retrofit { return Retrofit.Builder() .callFactory { client.get().newCall(it) } .build() }a @Inject constructor( retrofit: Retrofit )e 100-150ms! Background thread
34. Modularizing
35. @Module class MyGiantModule { @Provides fun provideSeasoning() = Seasoning() @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }a
36. @Module class MyGiantModuleBase { @Provides fun provideSeasoning() = Seasoning() }a @Module(includes = MyGiantModuleBase::class) class MyGiantModule { @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }b
37. @Module(includes = MyGiantModuleBase::class) class MyGiantModule { @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }b @Module class MyGiantModuleBase { @Provides fun provideSeasoning() = Seasoning() }a
38. @Module class MyGiantModule { @Provides fun provideSeasoning() = Seasoning() @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }a
39. @Module class SeasoningModule { @Provides fun provideSeasoning() = Seasoning() }b @Module(includes = SeasoningModule::class) class MyGiantModule { @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }a
40. @Module class SeasoningModule { @Provides fun provideSeasoning() = Seasoning() }b @Module(includes = [SeasoningModule::class, TacoModule::class]) class MyGiantModule @Module class TacoModule { @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }c
41. @Module class SeasoningModule { @Provides fun provideSeasoning() = Seasoning() }b @Module(includes = TacoModule::class) class MyGiantModule @Module(includes = SeasoningModule::class) class TacoModule { @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }c
42. @Module class SeasoningModule { @Provides fun provideSeasoning() = Seasoning() }b @Module(includes = SeasoningModule::class) class TacoModule { @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }c
43. class Seasoning @Inject constructor() class Taco @Inject constructor(seasoning: Seasoning)
44. class Taco @Inject constructor(seasoning: Seasoning) Food subproject Feature A
45. class Taco @Inject constructor(seasoning: Seasoning) Food subproject Feature A class Taco_Factory
46. class Taco @Inject constructor(seasoning: Seasoning) Food subproject Feature A class Taco_Factory Feature B class Taco_Factory
47. class Taco @Inject constructor(seasoning: Seasoning) Food subproject Feature A class Taco_Factory Feature B class Taco_Factory App
48. class Taco @Inject constructor(seasoning: Seasoning) Food subproject Feature A class Taco_Factory Feature B class Taco_Factory App
49. class Taco @Inject constructor(seasoning: Seasoning) Food subproject Feature A class Taco_Factory Feature B App
50. Internal APIs
51. @Module class FoodModule { @Provides fun provideSeasoning() = Seasoning() @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }
52. @Qualifier annotation class InternalApi
53. @Qualifier private annotation class InternalApi
54. @Qualifier private annotation class InternalApi @Module class FoodModule { @Provides fun provideSeasoning() = Seasoning() @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }a
55. @Qualifier private annotation class InternalApi @Module class FoodModule { @InternalApi @Provides fun provideSeasoning() = Seasoning() @Provides fun provideTaco(@InternalApi seasoning: Seasoning) = Taco(seasoning) }a
56. Multibindings
57. Multibindings • Set - @IntoSet, @ElementsIntoSet • Map - @IntoMap, @MapKey, etc
58. @Module class FoodModule { @Provides fun provideSeasoning() = Seasoning() @Provides fun provideTaco(seasoning: Seasoning) = Taco(seasoning) }a
59. @Module class FoodModule { @Provides fun provideSpicy() = SpicySeasoning() @Provides fun provideElPaso() = ElPasoSeasoning() @Provides fun provideTaco( spicy: SpicySeasoning, elpaso: ElPasoSeasoning ) = Taco(setOf(spicy, elpaso)) }a
60. @Module abstract class FoodModule { @Multibinds abstract fun seasonings(): Set<Seasoning> @Provides fun provideSpicy() = SpicySeasoning() @Provides fun provideElPaso() = ElPasoSeasoning() @Provides fun provideTaco( spicy: SpicySeasoning, elpaso: ElPasoSeasoning ) = Taco(setOf(spicy, elpaso)) }a
61. @Module abstract class FoodModule { @Multibinds abstract fun seasonings(): Set<Seasoning> @Provides @IntoSet fun provideSpicy() = SpicySeasoning() @Provides @IntoSet fun provideElPaso() = ElPasoSeasoning() @Provides fun provideTaco(seasonings: Set<Seasoning>) = Taco(seasonings) }a
62. @Module(includes = SeasoningModule::class) abstract class FoodModule { @Multibinds abstract fun seasonings(): Set<Seasoning> @Provides fun provideTaco(seasonings: Set<Seasoning>) = Taco(seasonings) }a @Module class SeasoningModule { @Provides @IntoSet fun provideSpicy() = SpicySeasoning() @Provides @IntoSet fun provideElPaso() = ElPasoSeasoning() }
63. @Module abstract class FoodModule { @Multibinds abstract fun seasonings(): Set<Seasoning> @Provides fun provideTaco(seasonings: Set<Seasoning>) = Taco(seasonings) }a
64. @Module abstract class NetworkModule { @Multibinds abstract fun interceptors(): Set<Interceptor> @Provides fun provideOkHttp(interceptors: Set<Interceptors>) = // ... }a
65. @Module abstract class DataModule { @Multibinds abstract fun adapters(): Set<JsonAdapter> @Provides fun provideMoshi(adapters: Set<JsonAdapter>) = // ... }a
66. @Module abstract class LoggingModule { @Multibinds abstract fun trees(): Set<Timber.Tree> }a
67. @Module abstract class PetsScreenModule { @Multibinds abstract fun categories(): Set<Category> }a
68. @Module abstract class PetsScreenModule { @Multibinds abstract fun categories(): Map<CategoryKey, Category> }a
69. @Module abstract class PetsScreenModule { @Multibinds abstract fun categories(): Map<CategoryKey, Lazy<Category>> }a
70. @Module abstract class PetsScreenModule { @Multibinds abstract fun categories(): Map<CategoryKey, Provider<Category>> }a
72. data class ScreenKey( val id: String )a
73. data class ScreenKey( val id: String, val xpId: String )a
74. data class ScreenKey( val id: String, val xpId: String )a class ScreenPresenter @Inject constructor( screens: Map<ScreenKey, Provider<Screen>>, private val xpManager: XpManager ) { private val finalScreens = screens.filterKeys { xpManager.isEnabled(it.xpId) } }
75. Dagger Party Tricks • github.com/ZacSweers/CatchUp • github.com/JakeWharton/sdksearch • github.com/JakeWharton/u2020 • Dagger Powered Plugin System post: https:// bit.ly/2T2Yqkl • Dependency Injection in a multi module project: https://bit.ly/2Gz5YFR @ZacSweers