我已經遵循了有關如何為自定義類型添加 TypeConverters 的房間文檔，但我仍然從我的實體類中收到錯誤消息。我想簡單地將Category枚舉轉換為 a，String以便房間數據庫了解如何存儲它。下面，每個Exercise都有一個類別，這就是發生錯誤的地方。這是我的課程：轉換器public class Converter {    @TypeConverter    public static String fromCategoryToString(Category category) {        if (category == null)            return null;        return category.toString();    }}類別public enum Category {    EXERCISE("Exercise"),    REST("Rest"),    COUNTDOWN("Countdown");    private final String text;    Category(final String text) {        this.text = text;    }    @Override    public String toString() {        return text;    }}鍛煉。為簡潔起見，刪除了 getter 和 setter。@Entity(tableName = "exercise",        foreignKeys = @ForeignKey(entity = Routine.class,                parentColumns = "rid",                childColumns = "routineId",                onDelete = ForeignKey.CASCADE),        indices = {@Index(value = "name", unique = true), @Index("routineId")})public class Exercise {    @PrimaryKey(autoGenerate = true)    @ColumnInfo(name = "eid")    private int exerciseID;    @ColumnInfo(name = "category")    private Category category; // error occurs here    @ColumnInfo(name = "name")    @NonNull    private String name;    @ColumnInfo(name = "routineId")    private int routineId;    public Exercise(Category category, @NonNull String name) {        this.category = category;        this.name = name;    }}數據庫@Database(entities = { Routine.class, Exercise.class}, version = 1)@TypeConverters({ Converter.class })public abstract class AppDatabase extends RoomDatabase {    private static AppDatabase instance;    private static final String dbName = "routines.db";    public abstract RoutineDao routineDao();    public abstract ExerciseDao exerciseDao();    public static AppDatabase getInstance(final Context context) {        if (instance == null) {            instance = Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, dbName).build();        }        return instance;    }}