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
   

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2. Dagger?
   

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3. Dagger Party Tricks
   

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4. 4ish Dagger Party Tricks
   

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5. Deferred
   Initialization
   

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9. @Provides fun provideRetrofit(): Retrofit {
   return Retrofit.Builder()
   .baseUrl("https://example.com")
   .build()
   }a
   

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10. @Provides fun provideClient(): OkHttpClient {
    return OkHttpClient.Builder()
    .build()
    }b
    @Provides fun provideRetrofit(client: OkHttpClient): Retrofit {
    return Retrofit.Builder()
    .client(client)
    .build()
    }a
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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18. Lazy!
    

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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
    

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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
    )e
    100-150ms!
    

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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
    )e
    100-150ms!
    retrofit.get().create(...)
    

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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
    )e
    100-150ms!
    retrofit.get().create(...)
    

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23. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit {
    return Retrofit.Builder()
    .client(client)
    .build()
    }a
    

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24. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit {
    return Retrofit.Builder()
    .callFactory(client)
    .build()
    }a
    

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25. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit {
    return Retrofit.Builder()
    .callFactory(client)
    .build()
    }a
    Call.Factory
    

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26. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit {
    return Retrofit.Builder()
    .callFactory(object : Call.Factory by client {})
    .build()
    }a
    

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27. @Provides fun provideRetrofit(client: OkHttpClient): Retrofit {
    return Retrofit.Builder()
    .callFactory { client.newCall(it) }
    .build()
    }a
    

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28. @Provides fun provideRetrofit(client: Lazy): Retrofit {
    return Retrofit.Builder()
    .callFactory { client.get().newCall(it) }
    .build()
    }a
    

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29. @Provides fun provideRetrofit(client: Lazy): Retrofit {
    return Retrofit.Builder()
    .callFactory { client.get().newCall(it) }
    .build()
    }a
    

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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
    )e
    100-150ms!
    retrofit.get().create(...)
    

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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
    )e
    100-150ms!
    retrofit.get().create(...)
    Main thread!
    

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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): Retrofit {
    return Retrofit.Builder()
    .callFactory { client.get().newCall(it) }
    .build()
    }a
    @Inject
    constructor(
    retrofit: Retrofit
    )e
    100-150ms!
    Background thread
    

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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): Retrofit {
    return Retrofit.Builder()
    .callFactory { client.get().newCall(it) }
    .build()
    }a
    @Inject
    constructor(
    retrofit: Retrofit
    )e
    100-150ms!
    Background thread
    

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34. Modularizing
    

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35. @Module
    class MyGiantModule {
    @Provides
    fun provideSeasoning() = Seasoning()
    @Provides
    fun provideTaco(seasoning: Seasoning) = Taco(seasoning)
    }a
    

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36. @Module
    class MyGiantModuleBase {
    @Provides
    fun provideSeasoning() = Seasoning()
    }a
    @Module(includes = MyGiantModuleBase::class)
    class MyGiantModule {
    @Provides
    fun provideTaco(seasoning: Seasoning) = Taco(seasoning)
    }b
    

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37. @Module(includes = MyGiantModuleBase::class)
    class MyGiantModule {
    @Provides
    fun provideTaco(seasoning: Seasoning) = Taco(seasoning)
    }b
    @Module
    class MyGiantModuleBase {
    @Provides
    fun provideSeasoning() = Seasoning()
    }a
    

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38. @Module
    class MyGiantModule {
    @Provides
    fun provideSeasoning() = Seasoning()
    @Provides
    fun provideTaco(seasoning: Seasoning) = Taco(seasoning)
    }a
    

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39. @Module
    class SeasoningModule {
    @Provides
    fun provideSeasoning() = Seasoning()
    }b
    @Module(includes = SeasoningModule::class)
    class MyGiantModule {
    @Provides
    fun provideTaco(seasoning: Seasoning) = Taco(seasoning)
    }a
    

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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
    

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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
    

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42. @Module
    class SeasoningModule {
    @Provides
    fun provideSeasoning() = Seasoning()
    }b
    @Module(includes = SeasoningModule::class)
    class TacoModule {
    @Provides
    fun provideTaco(seasoning: Seasoning) = Taco(seasoning)
    }c
    

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43. class Seasoning @Inject constructor()
    class Taco @Inject constructor(seasoning: Seasoning)
    

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44. class Taco @Inject constructor(seasoning: Seasoning)
    Food subproject
    Feature A
    

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45. class Taco @Inject constructor(seasoning: Seasoning)
    Food subproject
    Feature A
    class Taco_Factory
    

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46. class Taco @Inject constructor(seasoning: Seasoning)
    Food subproject
    Feature A
    class Taco_Factory
    Feature B
    class Taco_Factory
    

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47. class Taco @Inject constructor(seasoning: Seasoning)
    Food subproject
    Feature A
    class Taco_Factory
    Feature B
    class Taco_Factory
    App
    

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48. class Taco @Inject constructor(seasoning: Seasoning)
    Food subproject
    Feature A
    class Taco_Factory
    Feature B
    class Taco_Factory
    App
    

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49. class Taco @Inject constructor(seasoning: Seasoning)
    Food subproject
    Feature A
    class Taco_Factory
    Feature B
    App
    

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50. Internal APIs
    

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51. @Module
    class FoodModule {
    @Provides
    fun provideSeasoning() = Seasoning()
    @Provides
    fun provideTaco(seasoning: Seasoning) = Taco(seasoning)
    }
    

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52. @Qualifier
    annotation class InternalApi
    

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53. @Qualifier
    private annotation class InternalApi
    

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54. @Qualifier
    private annotation class InternalApi
    @Module
    class FoodModule {
    @Provides
    fun provideSeasoning() = Seasoning()
    @Provides
    fun provideTaco(seasoning: Seasoning) = Taco(seasoning)
    }a
    

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55. @Qualifier
    private annotation class InternalApi
    @Module
    class FoodModule {
    @InternalApi
    @Provides
    fun provideSeasoning() = Seasoning()
    @Provides
    fun provideTaco(@InternalApi seasoning: Seasoning) = Taco(seasoning)
    }a
    

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56. Multibindings
    

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57. Multibindings
    • Set - @IntoSet, @ElementsIntoSet
    • Map - @IntoMap, @MapKey, etc
    

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58. @Module
    class FoodModule {
    @Provides
    fun provideSeasoning() = Seasoning()
    @Provides
    fun provideTaco(seasoning: Seasoning) = Taco(seasoning)
    }a
    

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59. @Module
    class FoodModule {
    @Provides
    fun provideSpicy() = SpicySeasoning()
    @Provides
    fun provideElPaso() = ElPasoSeasoning()
    @Provides
    fun provideTaco(
    spicy: SpicySeasoning,
    elpaso: ElPasoSeasoning
    ) = Taco(setOf(spicy, elpaso))
    }a
    

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60. @Module
    abstract class FoodModule {
    @Multibinds abstract fun seasonings(): Set
    @Provides
    fun provideSpicy() = SpicySeasoning()
    @Provides
    fun provideElPaso() = ElPasoSeasoning()
    @Provides
    fun provideTaco(
    spicy: SpicySeasoning,
    elpaso: ElPasoSeasoning
    ) = Taco(setOf(spicy, elpaso))
    }a
    

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61. @Module
    abstract class FoodModule {
    @Multibinds abstract fun seasonings(): Set
    @Provides @IntoSet
    fun provideSpicy() = SpicySeasoning()
    @Provides @IntoSet
    fun provideElPaso() = ElPasoSeasoning()
    @Provides
    fun provideTaco(seasonings: Set) = Taco(seasonings)
    }a
    

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62. @Module(includes = SeasoningModule::class)
    abstract class FoodModule {
    @Multibinds abstract fun seasonings(): Set
    @Provides
    fun provideTaco(seasonings: Set) = Taco(seasonings)
    }a
    @Module
    class SeasoningModule {
    @Provides @IntoSet
    fun provideSpicy() = SpicySeasoning()
    @Provides @IntoSet
    fun provideElPaso() = ElPasoSeasoning()
    }
    

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63. @Module
    abstract class FoodModule {
    @Multibinds abstract fun seasonings(): Set
    @Provides
    fun provideTaco(seasonings: Set) = Taco(seasonings)
    }a
    

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64. @Module
    abstract class NetworkModule {
    @Multibinds abstract fun interceptors(): Set
    @Provides
    fun provideOkHttp(interceptors: Set) = // ...
    }a
    

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65. @Module
    abstract class DataModule {
    @Multibinds abstract fun adapters(): Set
    @Provides
    fun provideMoshi(adapters: Set) = // ...
    }a
    

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66. @Module
    abstract class LoggingModule {
    @Multibinds abstract fun trees(): Set
    }a
    

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67. @Module
    abstract class PetsScreenModule {
    @Multibinds
    abstract fun categories(): Set
    }a
    

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68. @Module
    abstract class PetsScreenModule {
    @Multibinds
    abstract fun categories(): Map
    }a
    

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69. @Module
    abstract class PetsScreenModule {
    @Multibinds
    abstract fun categories(): Map>
    }a
    

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70. @Module
    abstract class PetsScreenModule {
    @Multibinds
    abstract fun categories(): Map>
    }a
    

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72. data class ScreenKey(
    val id: String
    )a
    

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73. data class ScreenKey(
    val id: String,
    val xpId: String
    )a
    

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74. data class ScreenKey(
    val id: String,
    val xpId: String
    )a
    class ScreenPresenter @Inject constructor(
    screens: Map>,
    private val xpManager: XpManager
    ) {
    private val finalScreens = screens.filterKeys {
    xpManager.isEnabled(it.xpId)
    }
    }
    

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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
    

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