Android Hilt 依赖注入实战：从零搭建 Clean Architecture 注入体系

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\u4e3a\u4ec0\u4e48\u8981\u5728 Android \u9879\u76ee\u4e2d\u5f15\u5165 Hilt\uff1f

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\u4f9d\u8d56\u6ce8\u5165\uff08Dependency Injection\uff0cDI\uff09\u662f\u73b0\u4ee3 Android \u5f00\u53d1\u4e2d\u51e0\u4e4e\u65e0\u6cd5\u7ed5\u5f00\u7684\u8bdd\u9898\u3002\u624b\u52a8\u7ba1\u7406\u5bf9\u8c61\u4f9d\u8d56\u4e0d\u4ec5\u7e41\u7410\uff0c\u8fd8\u5bb9\u6613\u5728 Activity/Fragment \u751f\u547d\u5468\u671f\u4e2d\u5f15\u53d1\u5185\u5b58\u6cc4\u6f0f\u3002Google \u5b98\u65b9\u63a8\u8350\u7684 Hilt \u6846\u67b6\u57fa\u4e8e Dagger2\uff0c\u901a\u8fc7\u7f16\u8bd1\u671f\u4ee3\u7801\u751f\u6210\uff0c\u5728\u4fdd\u6301\u9ad8\u6027\u80fd\u7684\u540c\u65f6\u5927\u5e45\u964d\u4f4e\u4e86\u4e0a\u624b\u95e8\u69db\u3002

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\u672c\u6587\u4ee5\u4e00\u4e2a\u771f\u5b9e\u7684\u201c\u7528\u6237\u767b\u5f55 + \u6570\u636e\u52a0\u8f7d\u201d\u529f\u80fd\u4e3a\u7ebf\u7d22\uff0c\u5e26\u4f60\u4ece\u96f6\u641e\u5efa\u4e00\u5957\u7b26\u5408 Clean Architecture \u7684 Hilt \u6ce8\u5165\u4f53\u7cfb\uff0c\u8986\u76d6\u4ee5\u4e0b\u573a\u666f\uff1a

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• ViewModel \u4e2d\u6ce8\u5165 Repository

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• Repository \u4e2d\u6ce8\u5165 Retrofit \u548c Room

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• \u591a\u6a21\u5757\u9879\u76ee\u4e2d\u7684\u8de8\u6a21\u5757\u6ce8\u5165

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• \u5355\u5143\u6d4b\u8bd5\u4e2d\u66ff\u6362\u771f\u5b9e\u4f9d\u8d56

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\u7b2c\u4e00\u6b65\uff1a\u6dfb\u52a0\u4f9d\u8d56\u4e0e\u57fa\u7840\u914d\u7f6e

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\u5728\u9879\u76ee\u6839\u76ee\u5f55 build.gradle \u4e2d\u6dfb\u52a0 Hilt \u63d2\u4ef6\uff1a

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// \u6839\u76ee\u5f55 build.gradle\nplugins {\n    id \'com.google.dagger.hilt.android\' version \'2.51.1\' apply false\n}\n

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\u5728 app \u6a21\u5757 build.gradle \u4e2d\uff1a

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plugins {\n    id \'com.google.dagger.hilt.android\'\n    id \'kotlin-kapt\'\n}\n\ndependencies {\n    implementation "com.google.dagger:hilt-android:2.51.1"\n    kapt "com.google.dagger:hilt-android-compiler:2.51.1"\n    implementation "androidx.hilt:hilt-navigation-compose:1.2.0"\n}\n

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\u63a5\u7740\u7ed9 Application \u7c7b\u52a0\u4e0a @HiltAndroidApp \u6ce8\u89e3\uff0c\u8fd9\u662f Hilt \u7684\u5165\u53e3\uff0c\u4e0d\u80fd\u7701\u7565\uff1a

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@HiltAndroidApp\nclass MyApp : Application()\n

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\u522b\u5fd8\u4e86\u5728 AndroidManifest.xml \u4e2d\u6307\u5b9a android:name=".MyApp"\u3002

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\u7b2c\u4e8c\u6b65\uff1a\u6784\u5efa Network \u548c Database \u6a21\u5757

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Hilt \u901a\u8fc7 @Module + @InstallIn \u6765\u58f0\u660e\u5982\u4f55\u63d0\u4f9b\u4f9d\u8d56\u3002\u7f51\u7edc\u5c42\u548c\u6570\u636e\u5e93\u5c42\u901a\u5e38\u4f5c\u7528\u57df\u4e3a\u6574\u4e2a\u5e94\u7528\u751f\u547d\u5468\u671f\uff0c\u4f7f\u7528 SingletonComponent\uff1a

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@Module\n@InstallIn(SingletonComponent::class)\nobject NetworkModule {\n\n    @Provides\n    @Singleton\n    fun provideOkHttpClient(): OkHttpClient {\n        return OkHttpClient.Builder()\n            .addInterceptor(HttpLoggingInterceptor().apply {\n                level = HttpLoggingInterceptor.Level.BODY\n            })\n            .connectTimeout(30, TimeUnit.SECONDS)\n            .build()\n    }\n\n    @Provides\n    @Singleton\n    fun provideRetrofit(okHttpClient: OkHttpClient): Retrofit {\n        return Retrofit.Builder()\n            .baseUrl("https://api.example.com/")\n            .client(okHttpClient)\n            .addConverterFactory(GsonConverterFactory.create())\n            .build()\n    }\n\n    @Provides\n    @Singleton\n    fun provideUserApi(retrofit: Retrofit): UserApi {\n        return retrofit.create(UserApi::class.java)\n    }\n}\n

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\u6570\u636e\u5e93\u6a21\u5757\u540c\u7406\uff1a

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@Module\n@InstallIn(SingletonComponent::class)\nobject DatabaseModule {\n\n    @Provides\n    @Singleton\n    fun provideDatabase(@ApplicationContext context: Context): AppDatabase {\n        return Room.databaseBuilder(\n            context,\n            AppDatabase::class.java,\n            "app_database"\n        ).build()\n    }\n\n    @Provides\n    fun provideUserDao(database: AppDatabase): UserDao {\n        return database.userDao()\n    }\n}\n

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\u8e29\u5751\u63d0\u793a\uff1aUserDao \u4e0d\u52a0 @Singleton\uff0c\u56e0\u4e3a Room \u4f1a\u81ea\u5df1\u7ba1\u7406 DAO \u7684\u751f\u547d\u5468\u671f\uff0c\u91cd\u590d\u5305\u88c5\u53cd\u800c\u53ef\u80fd\u5f15\u53d1\u95ee\u9898\u3002

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\u7b2c\u4e09\u6b65\uff1a\u6ce8\u5165 Repository \u548c ViewModel

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Repository \u5c42\u8d1f\u8d23\u6574\u5408\u7f51\u7edc\u548c\u672c\u5730\u6570\u636e\u6e90\uff0c\u4f7f\u7528\u6784\u9020\u51fd\u6570\u6ce8\u5165\uff1a

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class UserRepository @Inject constructor(\n    private val userApi: UserApi,\n    private val userDao: UserDao\n) {\n    suspend fun login(username: String, password: String): Result<User> {\n        return try {\n            val user = userApi.login(LoginRequest(username, password))\n            userDao.insertUser(user)\n            Result.success(user)\n        } catch (e: Exception) {\n            Result.failure(e)\n        }\n    }\n\n    fun getCachedUser(): Flow<User?> = userDao.getUser()\n}\n

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ViewModel \u4e2d\u4f7f\u7528 @HiltViewModel + @Inject constructor\uff0c\u65e0\u9700\u624b\u52a8\u521b\u5efa ViewModelFactory\uff1a

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@HiltViewModel\nclass LoginViewModel @Inject constructor(\n    private val userRepository: UserRepository\n) : ViewModel() {\n\n    private val _loginState = MutableStateFlow<LoginState>(LoginState.Idle)\n    val loginState: StateFlow<LoginState> = _loginState.asStateFlow()\n\n    fun login(username: String, password: String) {\n        viewModelScope.launch {\n            _loginState.value = LoginState.Loading\n            val result = userRepository.login(username, password)\n            _loginState.value = if (result.isSuccess) {\n                LoginState.Success(result.getOrNull()!!)\n            } else {\n                LoginState.Error(result.exceptionOrNull()?.message ?: "\u767b\u5f55\u5931\u8d25")\n            }\n        }\n    }\n}\n

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\u5728 Activity/Fragment \u4e2d\u83b7\u53d6 ViewModel \u53ea\u9700\uff1a

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@AndroidEntryPoint\nclass LoginActivity : AppCompatActivity() {\n    private val viewModel: LoginViewModel by viewModels()\n}\n

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\u6ce8\u610f Activity \u5fc5\u987b\u52a0 @AndroidEntryPoint\uff0c\u5426\u5219 Hilt \u65e0\u6cd5\u6ce8\u5165\u3002

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\u7b2c\u56db\u6b65\uff1a\u5355\u5143\u6d4b\u8bd5\u4e2d\u66ff\u6362\u4f9d\u8d56

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Hilt \u5bf9\u6d4b\u8bd5\u7684\u652f\u6301\u975e\u5e38\u5b8c\u5584\uff0c\u901a\u8fc7 @TestInstallIn \u53ef\u4ee5\u66ff\u6362\u6b63\u5f0f\u6a21\u5757\uff1a

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@TestInstallIn(\n    components = [SingletonComponent::class],\n    replaces = [NetworkModule::class]\n)\n@Module\nobject FakeNetworkModule {\n\n    @Provides\n    @Singleton\n    fun provideUserApi(): UserApi = FakeUserApi()\n}\n

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\u6d4b\u8bd5\u7c7b\uff1a

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@HiltAndroidTest\nclass LoginViewModelTest {\n\n    @get:Rule\n    var hiltRule = HiltAndroidRule(this)\n\n    @Inject\n    lateinit var userRepository: UserRepository\n\n    @Before\n    fun init() {\n        hiltRule.inject()\n    }\n\n    @Test\n    fun testLoginSuccess() = runTest {\n        val viewModel = LoginViewModel(userRepository)\n        viewModel.login("test_user", "password123")\n        assertTrue(viewModel.loginState.value is LoginState.Success)\n    }\n}\n

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\u5e38\u89c1\u95ee\u9898\u4e0e\u6700\u4f73\u5b9e\u8df5

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• \u4f5c\u7528\u57df\u9009\u62e9\uff1aActivity \u5185\u7684\u4f9d\u8d56\u7528 ActivityComponent\uff0c\u907f\u514d Singleton \u6301\u6709 Activity \u5f15\u7528\u9020\u6210\u6cc4\u6f0f

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• @Qualifier \u533a\u5206\u540c\u7c7b\u578b\uff1a\u82e5\u6709\u591a\u4e2a OkHttpClient\uff0c\u7528 @Named \u6216\u81ea\u5b9a\u4e49 Qualifier \u533a\u5206

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• \u61d2\u52a0\u8f7d\uff1a\u7528 Lazy \u5305\u88c5\u4e0d\u9700\u8981\u7acb\u5373\u521d\u59cb\u5316\u7684\u4f9d\u8d56\uff0c\u51cf\u5c11\u542f\u52a8\u8017\u65f6

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• \u591a\u6a21\u5757\u9879\u76ee\uff1a\u6bcf\u4e2a feature \u6a21\u5757\u53ef\u4ee5\u6709\u81ea\u5df1\u7684 @InstallIn(ActivityComponent::class) \u6a21\u5757\uff0cHilt \u4f1a\u81ea\u52a8\u5408\u5e76

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• kapt \u7f16\u8bd1\u6162\uff1f\u5347\u7ea7\u5230 KSP \u53ef\u4ee5\u663e\u8457\u63d0\u5347\u7f16\u8bd1\u901f\u5ea6\uff0cHilt \u5df2\u652f\u6301 KSP

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\u638c\u63e1\u8fd9\u5957\u6a21\u5f0f\u540e\uff0c\u4f60\u4f1a\u53d1\u73b0\u4ee3\u7801\u53ef\u6d4b\u8bd5\u6027\u3001\u53ef\u7ef4\u62a4\u6027\u90fd\u6709\u8d28\u7684\u63d0\u5347\u3002\u4f9d\u8d56\u6ce8\u5165\u4e0d\u53ea\u662f\u6846\u67b6\u7684\u4f7f\u7528\uff0c\u66f4\u662f\u4e00\u79cd\u9762\u5411\u63a5\u53e3\u7f16\u7a0b\u7684\u601d\u7ef4\u65b9\u5f0f\u3002