相关疑难解决方法(0)

假设我正在制造一辆汽车,我有几个不同实施的刹车豆

class Car {
    @Inject
    Car(@BrakeType(value="abs")Brake frontBrake, @BrakeType(value="nonabs")Brake rearBrake) { }
}

@Qualifier
@Retention(RetentionPolicy.RUNTIME)
public @interface BrakeType {
    String value();
}

interface Brake {}

@BrakeType(value="abs")
class AbsBrakeImpl implements Brake {
    @Inject AbsBrakeImpl() {}
}

@BrakeType(value="nonabs")
class BrakeImpl implements Brake {
    @Inject BrakeImpl() {}
}

为什么我的CarModule必须为特定的制动类型定义@Provides？自定义注释类型@BrakeType不应该足以确定要注入哪个impl？或者这需要使用反射,dagger2不使用？

@Module
public class CarModule {
    @Provides @BrakeType("abs")
    public Brake absBrake() {
        return new AbsBrakeImpl();
    }
    @Provides @BrakeType("nonabs")
    public Brake nonabsBrake() {
        return new BrakeImpl();
    }
}

我怎么能得到像光标一样的多个相同返回类型的实例

例如 :-

Module
@CursorScope
public class CursorModule {


    @Provides
    Cursor provideSongCursor(
            @Named("Song") Musician musician) {
        return musician.getApplicationContext().getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                new String[]{
                        BaseColumns._ID,
                        MediaStore.Audio.AudioColumns.TITLE,
                        MediaStore.Audio.AudioColumns.ARTIST,
                        MediaStore.Audio.AudioColumns.ALBUM,
                        MediaStore.Audio.AudioColumns.DURATION
                }, MediaStore.Audio.AudioColumns.IS_MUSIC + "=1", null, null);
    }

    @Provides
    Cursor provideAlbumCursor(
            @Named("Album") Musician musician) {
        return musician.getApplicationContext().getContentResolver().query(MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI,
                new String[]{
                        BaseColumns._ID,
                        MediaStore.Audio.AlbumColumns.ALBUM,
                        MediaStore.Audio.AlbumColumns.ARTIST,
                        MediaStore.Audio.AlbumColumns.NUMBER_OF_SONGS,
                        MediaStore.Audio.AlbumColumns.FIRST_YEAR
                }, null, null, null);
    }

    @Provides
    Cursor provideArtistCursor(@Named("Artist") Musician musician) {
        return musician.getApplicationContext().getContentResolver().query(MediaStore.Audio.Artists.EXTERNAL_CONTENT_URI,
                new String[] {
                        BaseColumns._ID,
                        MediaStore.Audio.ArtistColumns.ARTIST,
                        MediaStore.Audio.ArtistColumns.NUMBER_OF_ALBUMS,
                        MediaStore.Audio.ArtistColumns.NUMBER_OF_TRACKS
                }, null, null,null);
    }

    @Provides
    Cursor provideGenreCursor(
            @Named("Genres") Musician musician) {
        return …