基于dagger2由google针对android平台开发的一个依赖注入库。
2 基本使用方法
2.1 在项目根级gradle添加class 插件
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| plugins {
...
id 'com.google.dagger.hilt.android' version '2.44' apply false
}
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2.2 在module 中添加依赖
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| ...
plugins {
id 'kotlin-kapt'
id 'com.google.dagger.hilt.android'
}
dependencies {
implementation "com.google.dagger:hilt-android:2.44"
kapt "com.google.dagger:hilt-compiler:2.44"
}
// Allow references to generated code
kapt {
correctErrorTypes true
}
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2.3 创建Application并添加@HiltAndroidApp注解,并在AndroidManifest.xml注册
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| @HiltAndroidApp
class HiltApp : Application()
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2.4 在依赖的android组件上添加@AndroidEntryPoint注解
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| @AndroidEntryPoint
class MainActivity : ComponentActivity() {
}
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2.5 使用@Provider注入实例
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| @InstallIn(SingletonComponent::class)
@Module
class ApplicationModule {
@Provides
fun provideBaseUrl() = BuildConfig.BASE_URL
@Provides
@Singleton
fun provideOkHttpClient() = if (BuildConfig.DEBUG) {
val loggingInterceptor = HttpLoggingInterceptor()
loggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY)
OkHttpClient.Builder()
.addInterceptor(loggingInterceptor)
.build()
} else OkHttpClient
.Builder()
.build()
@Provides
@Singleton
fun provideRetrofit(
okHttpClient: OkHttpClient,
BASE_URL: String
): Retrofit =
Retrofit.Builder()
.addConverterFactory(MoshiConverterFactory.create())
.baseUrl(BASE_URL)
.client(okHttpClient)
.build()
@Provides
@Singleton
fun provideApiService(retrofit: Retrofit): ApiService = retrofit.create(ApiService::class.java)
@Provides
@Singleton
fun provideApiHelper(apiHelper: ApiHelperImpl): ApiHelper = apiHelper
}
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2.6 使用@bind注入接口实例
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| interface AnalyticsService {
fun analyticsMethods()
}
// Constructor-injected, because Hilt needs to know how to
// provide instances of AnalyticsServiceImpl, too.
class AnalyticsServiceImpl @Inject constructor(
...
) : AnalyticsService { ... }
@Module
@InstallIn(ActivityComponent::class)
abstract class AnalyticsModule {
@Binds
abstract fun bindAnalyticsService(
analyticsServiceImpl: AnalyticsServiceImpl
): AnalyticsService
}
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2.7 同一类型的不同实现
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| @Qualifier
@Retention(AnnotationRetention.RUNTIME)
annotation class LocalData
@Qualifier
@Retention(AnnotationRetention.RUNTIME)
annotation class RemoteData
@InstallIn(SingletonComponent::class)
@Module
object DataModule{
@LocalData
@Provides
fun provideLocalData() = "LocalData"
@RemoteData
@Provides
fun provideRemoteData() = "RemoteData"
}
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2.8 构造函数注入
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| class User @Inject constructor()
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2.9 使用@Inject注入User对象
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| @Inject
lateinit var user: User
@Inject
lateinit var user2: User
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3 和viewModel 搭配使用
提供 ViewModel，方法是为其添加 @HiltViewModel 注解，并在 ViewModel 对象的构造函数中使用 @Inject 注解
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| @HiltViewModel
class ExampleViewModel @Inject constructor(
private val savedStateHandle: SavedStateHandle,
private val repository: ExampleRepository
) : ViewModel() {
...
}
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| @AndroidEntryPoint
class ExampleActivity : AppCompatActivity() {
private val exampleViewModel: ExampleViewModel by viewModels()
...
}
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许你一世凡尘
收录于 android lib