Java 放低品位方法或MLite上的表格

当调用

OrmLiteSqliteOpenHelper

类的

ondownggrade

方法时，我需要删除数据库表

@Override
public void onUpgrade(SQLiteDatabase db, ConnectionSource connectionSource, int oldVersion, int newVersion) {
    try {
        Log.i(DatabaseHelper.class.getName(), "onUpgrade");
        TableUtils.dropTable(connectionSource, DbFeedJsonRow.class, true);
        TableUtils.dropTable(connectionSource, DbEventJsonRow.class, true); //TODO REMOVE
        TableUtils.dropTable(connectionSource, DbTeamJsonRow.class, true);
        TableUtils.dropTable(connectionSource, DbFavoritePlayerDTO.class, true);
        TableUtils.dropTable(connectionSource, DbAssetDTO.class, true);
        TableUtils.dropTable(connectionSource, DbTaskDTO.class, true);
        TableUtils.dropTable(connectionSource, DbEventDTO.class, true);
        // after we drop the old databases, we create the new ones
        onCreate(db, connectionSource);
    } catch (SQLException e) {
        Log.e(DatabaseHelper.class.getName(), "Can't drop databases", e);
        throw new RuntimeException(e);
    }
}

@Override
public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    try {
        Log.i(DatabaseHelper.class.getName(), "onDowngrade");
        TableUtils.dropTable(connectionSource, DbFeedJsonRow.class, true);
        TableUtils.dropTable(connectionSource, DbEventJsonRow.class, true); //TODO REMOVE
        TableUtils.dropTable(connectionSource, DbTeamJsonRow.class, true);
        TableUtils.dropTable(connectionSource, DbAssetDTO.class, true);
        TableUtils.dropTable(connectionSource, DbTaskDTO.class, true);
        TableUtils.dropTable(connectionSource, DbEventDTO.class, true);
        // after we drop the old databases, we create the new ones
        onCreate(db, connectionSource);
    } catch (SQLException e) {
        Log.e(DatabaseHelper.class.getName(), "Can't drop databases", e);
        throw new RuntimeException(e);
    }
}

onUpgrade

工作正常，但是

onDowngrade

方法抛出异常，表示正在重复调用

getWritableDatabase（）

方法

---

有什么提示吗？我只想删除我的表并重新创建它们，不管数据库版本代码是新的还是旧的。

继OrmLite作者之前的回答之后：

您可以保存连接源并将其传递到drop表调用中，如下所示：

@Override
public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    ConnectionSource cs = getConnectionSource();
    /*
     * The method is called by Android database helper's get-database calls when Android detects that we need to
     * create or update the database. So we have to use the database argument and save a connection to it on the
     * AndroidConnectionSource, otherwise it will go recursive if the subclass calls getConnectionSource().
     */
    DatabaseConnection conn = cs.getSpecialConnection();
    boolean clearSpecial = false;
    if (conn == null) {
        conn = new AndroidDatabaseConnection(db, true);
        try {
            cs.saveSpecialConnection(conn);
            clearSpecial = true;
        } catch (SQLException e) {
            throw new IllegalStateException("Could not save special connection", e);
        }
    }
    try {
        dropTables(cs);
        createTables(cs);
    } catch (SQLException e) {
        // log something
    } finally {
        if (clearSpecial) {
            cs.clearSpecialConnection(conn);
        }
    }
}

private void createTables(ConnectionSource connectionSource) throws SQLException {
    TableUtils.createTable(connectionSource, YourTableObject.class);
}

public void dropTables(ConnectionSource connectionSource) throws SQLException{
    TableUtils.dropTable(connectionSource, YourTableObject.class, true);
}

---

很好，我最终连接了

onConfigure（SQLiteDatabase）

将旧数据库版本保存在一个变量中，并使用该变量将表放到

DatabaseHelper

生命周期之外。但我认为你的解决办法是正确的。