没有使用 Dagger 获得单例

Question

我刚刚开始在我当前的 Android 应用程序中使用 Dagger，我不确定如何实现我正在寻找的功能（我相信我正在寻找什么是可能）。

基本上我的情况是这样的。我有以下 classes 我想让它们的 instances/injections 由 Dagger 管理。我还希望其中一些是单例，由 (1) 指出：

CipherFactory - 简单的包私有工厂
CryptoService (1) - 依赖于 CipherFactory
SerializationService (1) - 依赖于 Jackson 的 ObjectMapper
PlayerApplicationService (1) - 依赖于 SerializationService
PlayerRepository (1) - 依赖于 SerializationService、CryptoService

现在，我可以让 Dagger 创建这些服务并适当地注入它们的依赖关系；问题是一些 classes 依赖于多个 class 并且通过日志记录语句显示每次注入时我都会得到 new 个实例.

这是我目前拥有的上述内容，包括 Dagger 模块 classes:

CryptoService.java

@Singleton
public class CryptoService {
    private final CipherFactory cipherFactory;

    @Inject
    CryptoService(CipherFactory cipherFactory) {
        this.cipherFactory = cipherFactory;
    }
    ...
}

CryptoServiceModule.java

@Module(
        injects = CryptoService.class,
        complete = true,
        library = true
)
public class CryptoServiceModule {

    @Provides
    @Singleton
    CipherFactory provideCipher() {
        return new CipherFactory();
    }

}

SerializationService.java

@Singleton
public class SerializationService {

    private final ObjectMapper objectMapper;

    @Inject
    SerializationService(ObjectMapper objectMapper) {
        this.objectMapper = objectMapper;
    }
    ...
}

SerializationServiceModule.java

@Module(
        injects = SerializationService.class,
        library = true,
        complete = true
)
public class SerializationServiceModule {

    @Provides
    @Singleton
    ObjectMapper provideMapper() {
        return new ObjectMapper();
    }

}

PlayerApplicationService.java

public class PlayerApplicationService {

    private SerializationService serializationService;

    @Inject
    public PlayerApplicationService(SerializationService serializationService) {
        this.serializationService = serializationService;
    }
    ....
}

PlayerApplicationServiceModule.java

@Module(
        injects = PlayerApplicationService.class,
        includes = {
                SerializationServiceModule.class
        },
        complete = true,
        library = true
)
public class PlayerApplicationServiceModule {
}

PlayerRepository.java

@Singleton
public class PlayerRepository implements Repository<Player> {

    private final SerializationService serializationService;
    private final CryptoService cryptoService;

    @Inject
    public PlayerRepository(SerializationService serializationService, CryptoService cryptoService) {
        this.serializationService = serializationService;
        this.cryptoService = cryptoService;
    }
    ...
}

PlayerRepositoryModule.java

@Module(
        injects = PlayerRepository.class,
        includes = {
                SerializationServiceModule.class,
                CryptoServiceModule.class
        },
        complete = true,
        library = true
)
public class PlayerRepositoryModule {
}

我错过了什么？正如我上面提到的，所有这些东西按原样工作，看起来我得到了一些依赖项的多个实例（例如，SerializationService，它被两个 classes) 在我只有 want/need 一个的地方创建。

Answer 1

根据@Andyccs 的评论，我已将所有内容合并到一个应用程序级模块 class 并删除了应用程序中的所有其他模块 class：

PlayerApplicationModule.java

@Module(
        injects = {
                PlayerApplication.class,
                CryptoService.class,
                SerializationService.class,
                PlayerApplicationService.class
        },
        complete = true,
        library = true
)
public class PlayerApplicationModule {
    private PlayerApplication application;

    public PlayerApplicationModule(PlayerApplication application) {
        this.application = application;
    }

    @Provides
    @Singleton
    public Context provideApplicationContext() {
        return application;
    }

    @Provides
    @Singleton
    public CipherFactory provideCipherFactory() {
        return new CipherFactory();
    }

    @Provides
    @Singleton
    public ObjectMapper provideObjectMapper() {
        return new ObjectMapper();
    }

}

现在一切正常。

没有使用 Dagger 获得单例

Not getting singletons using Dagger

java

singleton

android

dagger