带有Kotlin的Dagger 2,在ApplicationComponent中返回带泛型的类型

Question

我想返回带有泛型的类型,通过子图公开,问题出在自动生成的java类中,我试着做一些事情,但解决它的一种方法是从AppComponent中删除泛型类型并返回简单对象.有更"正确"的方法吗？

这是AppComponent

@Singleton
@Component(modules = arrayOf(ApplicationModule::class))
interface ApplicationComponent {
    fun inject(activity: BaseActivity<MvpView, MvpPresenter<MvpView>>)

    //...
    fun dataBase(): Database<Realm>
}

这是ApplicationModule中的函数

@Provides @Singleton fun provideDatabase(@AppContext context: App): Database<Realm> {
    Realm.init(context)
    val config = RealmConfiguration.Builder()
            .deleteRealmIfMigrationNeeded()
            .name("db")
            .build()
    Realm.setDefaultConfiguration(config)
    return RealmDatabase(Realm.getDefaultInstance())
}

然后我想收到我的数据库

@Provides @ActivityScope fun provideDich(database: Database<Realm>) = Someobject(database)

然后我看到日志说:

**Error:com.test.data.storage.Database<? extends io.realm.Realm> cannot be provided without an @Provides-annotated method.**

因为dagger2生成这样的工厂并且有java掩码

    public final class Logout_Factory implements Factory<Logout> {
  private final MembersInjector<Logout> logoutMembersInjector;

  private final Provider<SessionStorage.CloudStorage> arg0Provider;

  private final Provider<Database<? extends Realm>> arg1Provider;

  public Logout_Factory(
      MembersInjector<Logout> logoutMembersInjector,
      Provider<SessionStorage.CloudStorage> arg0Provider,
      Provider<Database<? extends Realm>> arg1Provider) {
    assert logoutMembersInjector != null;
    this.logoutMembersInjector = logoutMembersInjector;
    assert arg0Provider != null;
    this.arg0Provider = arg0Provider;
    assert arg1Provider != null;
    this.arg1Provider = arg1Provider;
  }

  @Override
  public Logout get() {
    return MembersInjectors.injectMembers(
        logoutMembersInjector, new Logout(arg0Provider.get(), arg1Provider.get()));
  }

  public static Factory<Logout> create(
      MembersInjector<Logout> logoutMembersInjector,
      Provider<SessionStorage.CloudStorage> arg0Provider,
      Provider<Database<? extends Realm>> arg1Provider) {
    return new Logout_Factory(logoutMembersInjector, arg0Provider, arg1Provider);
  }
}

Answer 1

我有同样的问题,我找到了解决方案.

你需要声明@JvmWildcard你的@Provide方法的返回类型.

@Provides 
@Singleton 
fun provideDatabase(@AppContext context: App): Database<@JvmWildcard Realm> {
    Realm.init(context)
    val config = RealmConfiguration.Builder()
            .deleteRealmIfMigrationNeeded()
            .name("db")
            .build()
    Realm.setDefaultConfiguration(config)
    return RealmDatabase(Realm.getDefaultInstance())
}