java - Android Studio 房间类型转换器的问题

Question

出于某种原因，我在 Android Studio 中遇到类型转换器问题。我尝试了其他帖子中的各种解决方案，但仍然出现此错误。当我尝试使用字符串数组列表而不是成分时，类型转换器确实可以工作。

错误:无法弄清楚如何将此字段保存到数据库中。您可以考虑为其添加类型转换器。

@Entity(tableName = "Recipes")
    public class recipesDB {
        @PrimaryKey
        @NonNull
        @ColumnInfo(name = "recipeID")
        private int id;

    //Foreign Key to be used from Ingredients
    @ColumnInfo(name = "name")
    private String name;

    @ColumnInfo(name = "url")
    private String url;

    @ColumnInfo(name = "readyInMinutes")
    private int readyInMinutes;

//Issue Here
@ColumnInfo(name = "ingredients")
private ArrayList<ingredient> ingredients;

数据转换器类:

public class DataConverter{


    @TypeConverter
    public static ArrayList<ingredient> toIngredient(String s){
        if(s == null){
            return null;
        }

        Gson gson = new Gson();
        Type listType = new TypeToken<ArrayList<ingredient>>(){}.getType();
        ArrayList<ingredient> ingredients = gson.fromJson(s, listType);
        return ingredients;
    }

    @TypeConverter
    public static String getIngredients(ArrayList<ingredient> ingredients){
        if(ingredients == null){
            return null;
        }

        Gson gson = new Gson();
        Type type = new TypeToken<ArrayList<ingredient>>() {}.getType();
        String json = gson.toJson(ingredients);
        return json;
    }

编辑 应用程序数据库:

@Database(entities = {recipesDB.class}, version = 1, exportSchema = false)
@TypeConverters({DataConverter.class})
public abstract class AppDatabase extends RoomDatabase {
    private static AppDatabase INSTANCE;
    public abstract recipesDAO recipesdao();
    //public abstract pantryDAO pantrydao();
    public static AppDatabase getInMemoryDatabase(Context context) {
        if (INSTANCE == null) {
            INSTANCE = Room.inMemoryDatabaseBuilder(context.getApplicationContext(), AppDatabase.class).build();
        }
        return INSTANCE;
    }
    public static void destroyInstance(){INSTANCE = null;}
}

Answer 1

所以问题的原因是由于我当前文件夹目录范围之外的重复成分类。通过将类别成分更改为 Ingredient，它一定可以消除 Room 的困惑。