我可以将一个TypeConverter用于不同的对象类型吗? [英] Can I use one single TypeConverter for different object types?

问题描述

到目前为止，为了存储在房间数据库中，我一直在为每个类使用类型转换器.像这样:

So far for storing in Room Database I've been using type converter for each classes. Like this:

@SerializedName("sidebar")
@Expose
@TypeConverters(SidebarConverter.class)
private Sidebar sidebar;
@SerializedName("splash")
@Expose
@TypeConverters(SplashConverter.class)
private Splash splash;
@SerializedName("overview")
@Expose
@TypeConverters(OverviewConverter.class)
private Overview overview;
@SerializedName("home")
@Expose
@TypeConverters(HomeConverter.class)
private Home home;
@SerializedName("portfolio")
@Expose
@TypeConverters(PortfolioConverter.class)
private Portfolio portfolio;
@SerializedName("team")
@Expose
@TypeConverters(TeamConverter.class)
private Team team;

我想知道是否有更方便的方法在数据库中单手使用一个TypeConverter.

I want to know if there's a more convenient way to use one TypeConverter single handedly in Database.

推荐答案

您可以在单个类中定义所有转换器，如下所示:

You can define all your converter in a Single Class like this:

public class DateTypeConverter {

    @TypeConverter
    public static Date toDate(Long value) {
        return value == null ? null : new Date(value);
    }

    @TypeConverter
    public static Long toLong(Date value) {
        return value == null ? null : value.getTime();
    }
}

然后在会议室数据库中使用类似这样的@TypeConverter注释设置此转换器，该注释可在任何@Entity类上全局运行.您无需在Entity类中单独定义@TypeConverter

And then set this converter on your Room Database with @TypeConverter annotation like this which work globally on any @Entity class.You don't need to define @TypeConverter Individually in Entity class

@Database(entities = {Product.class}, version = 1)
@TypeConverters({DateTypeConverter.class})
public abstract class MyDatabase extends RoomDatabase {
    public abstract ProductDao productDao();
}

请注意，我们在数据库定义中添加了一个名为@TypeConverters的新注释，以引用我们可以拥有的不同转换器(您可以用逗号分隔并添加其他注释).

Note we’ve added a new annotation named @TypeConverters in our database definition in order to reference the different converters that we can have (you can separate it by commas and add others).

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