如何在Hilt单例模块中为OkHttp拦截器获取LifecycleOwner？

问题核心 #

OkHttpClient属于单例作用域（SingletonComponent），而LifecycleOwner（如Activity、Fragment）是页面级作用域，生命周期远短于单例。直接在单例拦截器中注入LifecycleOwner会触发Hilt作用域不匹配的错误，还可能导致内存泄漏。

解决方案：通过动态持有类中转 #

1. 创建单例的Lifecycle持有者类 #

用来临时存储当前活跃的LifecycleOwner：

class LifecycleHolder @Inject constructor() {
    @Volatile
    var currentLifecycleOwner: LifecycleOwner? = null
}

2. 修改拦截器，依赖LifecycleHolder #

不再直接持有LifecycleOwner，而是通过持有者动态获取：

class MyInterceptor @Inject constructor(
    private val lifecycleHolder: LifecycleHolder
) : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        val currentOwner = lifecycleHolder.currentLifecycleOwner
        // 使用时必须判空，避免无活跃页面时出现空指针
        currentOwner?.let { owner ->
            // 示例：监听生命周期事件
            owner.lifecycle.addObserver(object : LifecycleEventObserver {
                override fun onStateChanged(source: LifecycleOwner, event: Lifecycle.Event) {
                    // 处理逻辑
                    // 记得用完移除观察者，防止内存泄漏
                    source.lifecycle.removeObserver(this)
                }
            })
        }
        return chain.proceed(chain.request())
    }
}

3. 调整Hilt模块配置 #

让Hilt管理LifecycleHolder和拦截器的依赖，确保都是单例：

@Module
@InstallIn(SingletonComponent::class)
object AppEntryModule {
    @Provides
    @Singleton
    fun provideLifecycleHolder(): LifecycleHolder = LifecycleHolder()

    @Provides
    @Singleton
    fun provideMyInterceptor(lifecycleHolder: LifecycleHolder): MyInterceptor =
        MyInterceptor(lifecycleHolder)

    @Provides
    @Singleton
    fun provideOkHttpClient(interceptor: MyInterceptor): OkHttpClient =
        OkHttpClient.Builder()
            .addInterceptor(interceptor)
            .build()

    @Provides
    @Singleton
    fun provideRetrofit(client: OkHttpClient): Retrofit =
        Retrofit.Builder()
            .baseUrl(MOCK_URL)
            .client(client)
            .addConverterFactory(GsonConverterFactory.create())
            .build()
}

4. 在页面中动态更新LifecycleOwner #

在BaseActivity或BaseFragment的生命周期方法中，更新持有者的当前LifecycleOwner：

abstract class BaseActivity : AppCompatActivity() {
    @Inject
    lateinit var lifecycleHolder: LifecycleHolder

    override fun onResume() {
        super.onResume()
        // 页面活跃时设置当前Activity为LifecycleOwner
        lifecycleHolder.currentLifecycleOwner = this
    }

    override fun onPause() {
        super.onPause()
        // 页面失活时清空，避免持有已销毁的Activity引用
        lifecycleHolder.currentLifecycleOwner = null
    }
}

如果是Fragment，推荐使用viewLifecycleOwner更安全：

abstract class BaseFragment : Fragment() {
    @Inject
    lateinit var lifecycleHolder: LifecycleHolder

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        viewLifecycleOwner.lifecycle.addObserver(object : LifecycleEventObserver {
            override fun onStateChanged(source: LifecycleOwner, event: Lifecycle.Event) {
                when(event) {
                    Lifecycle.Event.ON_RESUME -> {
                        lifecycleHolder.currentLifecycleOwner = source
                    }
                    Lifecycle.Event.ON_PAUSE -> {
                        lifecycleHolder.currentLifecycleOwner = null
                    }
                    else -> {}
                }
            }
        })
    }
}

注意事项 #

• 必须在页面失活时清空LifecycleHolder的引用，防止内存泄漏。
• 拦截器中使用LifecycleOwner前一定要判空，避免App在后台发起请求时出现空指针。

内容的提问来源于stack exchange，提问作者Dmitry Sergienko