数据库正在尝试更新其版本，但是由于升级是一种写操作，因此无法在您请求的只读数据库上完成，因此会出现错误

The database is trying to update it's version, but since upgrading is a writing operation it can not be done on the read only database you are requesting, hence the error.

public Cursor getChampions() {
    SQLiteDatabase db = getWritableDatabase();
    db.close();
    db = getReadableDatabase();
    SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
    ....
}

这将首先创建一个可写数据库，升级数据库，然后您可以使用只读数据库. 请注意，运行此代码后，您可以删除这些行.

This will create a writable database first, upgrade the database, and then you can use a read-only database. Note that after running this code you can remove those lines.