IllegalArgumentException：版本必须 >= 1，为 0。在带有 Room 数据库的 Android Studio 中

Question

我正在尝试将我称为 QuesDto 的简单对象保存到 Room 数据库。

我检查了所有内容，但无法弄清楚为什么会出现此异常：

FATAL EXCEPTION: pool-3-thread-1
    Process: ovh.lahmadi.naditutoadmin, PID: 7753
    java.lang.IllegalArgumentException: Version must be >= 1, was 0
        at android.database.sqlite.SQLiteOpenHelper.<init>(SQLiteOpenHelper.java:164)
        .......

这是我的房间数据库摘要class:

@Database(entities = {QuesDto.class}, version = 0, exportSchema = false)
public abstract class QuizRoomDB extends RoomDatabase {

    private static volatile QuizRoomDB INSTANCE;
    public abstract QuizDao wordDao();
    .....

    public static QuizRoomDB getDatabase(Context context){
        if (INSTANCE == null){
            synchronized (QuizRoomDB.class){
                if (INSTANCE == null){
                        INSTANCE = Room.databaseBuilder(context.getApplicationContext(), QuizRoomDB.class, "quiz_db")
                                .build();
                }
            }
        }
        return INSTANCE;
    }
}

My Dao 界面：

@Dao
public interface QuizDao {
    @Insert (onConflict = OnConflictStrategy.IGNORE)
    void insert(QuesDto quesDto);
}

我的实体：

@Entity (tableName = "ques")
public class QuesDto {
    @PrimaryKey
    @NonNull
    private long quesId;
    private String quesHtml;
    ......
}

插入函数的调用方式：

    public QuestionRepository(Application application) {
        this.context = application.getApplicationContext();
        .....
    }

    public void saveQuesLocally(QuesDto quesDto) {
        QuizRoomDB db = QuizRoomDB.getDatabase(context);
        QuizDao quizDao = db.wordDao();
        Log.d(N.Room, "QuestionRepository. inside saveQuesLocally");
        new Thread(() -> {           
            QuizRoomDB.dbWriteExecutor.execute(()-> quizDao.insert(quesDto));
        }).start();
    }

感谢您的帮助。

Answer 1

由于以下内部逻辑而发生错误：

 if (version < 1) throw new IllegalArgumentException("Version must be >= 1, was " + version);

SQLiteOpenHelper 代码为：https://android.googlesource.com/platform/frameworks/base/+/74f170f9468d3cf6d7d0ef453320141a3e63571b/core/java/android/database/sqlite/SQLiteOpenHelper.java

您需要更改 class 中的版本 1:

@Database(entities = {QuesDto.class}, version = 1, exportSchema = false)
public abstract class QuizRoomDB extends RoomDatabase {

}

Answer 2

改变

@Database(entities = {QuesDto.class}, version = 0, exportSchema = false)

至

@Database(entities = {QuesDto.class}, version = 1, exportSchema = false)

查看 here 了解更多详情。

IllegalArgumentException：版本必须 >= 1，为 0。在带有 Room 数据库的 Android Studio 中

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