Question

我正在尝试为我的Android应用创建一个Room数据库，我遇到了自定义对象数组的问题。

错误讯息：

java.lang.IllegalArgumentException: cz.polreich.banks.model.airBank.OpeningHoursDay[]cannot be converted to an Element

这是嵌入有问题数组的对象：

@Entity
public class OpeningHours  {

@PrimaryKey(autoGenerate = true)
private int ohId;
private boolean isNonstop;
@Embedded
private OpeningHoursDay[] days;

public OpeningHours() {
}

// getters and setters

这是我的数据库定义：

@Database(version = 1, entities = {OpeningHours.class, OpeningHoursDay.class})
abstract class AppDatabase extends RoomDatabase {
@TypeConverters({Converters.class})

abstract public BranchDao branchDao();
}

我也有类型转换器，我希望，通过将数组转换为List并返回来解决这个问题，但它没有帮助：

public class Converters {
@TypeConverter
public List<OpeningHoursDay> fromOpeningHoursDayArray(OpeningHoursDay[] ohda){
    List<OpeningHoursDay> ohdList = new ArrayList<>();
    ohdList.addAll(Arrays.asList(ohda));
    return ohdList;
}

@TypeConverter
public OpeningHoursDay[] toOpeningHoursDayArray(List<OpeningHoursDay> ohdList){
    OpeningHoursDay[] ohda = null;
    for (int i = 0; i < ohdList.size(); i++) {
        ohda[i] = ohdList.get(i);
    }
    return ohda;
}
}

修改我试图更改TypeConverter以将对象转换为json，但它没有帮助：

public class Converters {

Gson gson = new Gson();

@TypeConverter
public String fromOpeningHoursDayArray(OpeningHoursDay[] ohda){
    ArrayList<OpeningHoursDay> ohdList = new ArrayList<>();
    ohdList.addAll(Arrays.asList(ohda));
    return gson.toJson(ohdList);
}

@TypeConverter
public OpeningHoursDay[] toOpeningHoursDayArray(String ohdJson){
    ArrayList<OpeningHoursDay> ohdList = new ArrayList<>();
    ohdList = gson.fromJson(ohdJson, new TypeToken<ArrayList<OpeningHoursDay>>(){}.getType());
    OpeningHoursDay[] ohda = null;
    for (int i = 0; i < ohdList.size(); i++) {
        ohda[i] = ohdList.get(i);
    }
    return ohda;
}

}

有谁知道如何解决这个问题？

Answer 1

删除自定义对象数组的@Embedded注释修复了该问题。

房间数据库中的自定义对象数组

1 个答案: