Android Sql 空指针异常

Question

我在 Android SQL 查询方面遇到了一些问题。

这是我的代码：

        Communicator rpc;
        dbHelper = new DataBaseHelper(context, "oops_sys_tpl.sqlite", null, 1);
        dbHelper.getDatabase();
        dbHelper.executeQuery("users", "id", "75");
        dbHelper.executeQuery("users", "objectId", "2");
        dbHelper.executeQuery("users","serverName","ooops.com");
        dbHelper.executeQuery("users", "username", "muphet");

        newServerName = "stampii.com";
        Log.w("UserId","Show user Id : "+userId);
        int uuId = rpc.localUserIdByServerUserId(userId,newServerName);
        Log.w("uuId","uuId : "+uuId);

在 Communicator 类中：

public static int localUserIdByServerUserId(int serverUserId){

    String query = "SELECT id FROM users WHERE objectId = "+serverUserId+" LIMIT 1";
    Map<String,Object> result = new HashMap<String,Object>();
    result.get(dbHelper.executeSQLQuery(query));

    int uuid = Integer.parseInt(result.get(0).toString());
    return uuid;
}

public static int localUserIdByServerUserId(int serverUserId, String serverName){

    String query = "SELECT id FROM users WHERE objectId = "+serverUserId+" AND serverName = "+serverName+" LIMIT 1";
    Map<String,Object> result = new HashMap<String,Object>();
    result.get(dbHelper.executeSQLQuery(query));

    int uuid = Integer.parseInt(result.get(0).toString());
    Log.w("localUSerByIdServerUserId","LocalUserByIdServerUserId result : "+uuid);
    return uuid;
}

在 DatabaseHelper 类中：

SQLIteDatabase sqliteDb;
   public boolean executeQuery(String tableName,String keys,String value){
        return execQuery(tableName,keys,value);
    }

    private static boolean execQuery(String tableName,String key,String value){
        sqliteDb = instance.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(key, value);
        sqliteDb.insert(tableName, null, values);

        return true;

    }

它向我抛出一个 NullPointerException：

result.get(dbHelper.executeSQLQuery(query));

有什么建议我可以解决这个问题吗？

Answer 1

您在此行中调用的方法： result.get(dbHelper.executeSQLQuery(query)); 和您在此处显示的方法 public booleanexecuteQuery() 是不同的一个，所以我猜问题出在另一个。检查一下，您会找到答案，或将其粘贴到此处，以便我们为您提供帮助。