Question

我有QList<m_User>

m_User {
    QString status;
    QString firstName;
    QString lastName;
    QDate joinDate;
    QDate leaveDate;
}

status此处可以是：terminated，in test，requested，activated。

status的排序顺序应为：activated - ＆gt; terminated - ＆gt; requested - ＆gt; in test

此QList应按此顺序排序：

状态（如上所述）
如果状态相同，我们按字母顺序排序firstName，这次是
如果firstName相同，我们按字母顺序排序lastName

所以结果看起来应该是

----------------------------------------------------------
| firstName | lastName |  status  | joinDate | leaveDate |
----------------------------------------------------------
|     A     |    C     |activated |   bla    |    bla    |
|     A     |    D     |activated |   bla    |    bla    | 
|     B     |    E     |activated |   bla    |    bla    |

|     A     |    F     |terminated|   bla    |    bla    | 
|     A     |    G     |terminated|   bla    |    bla    | 
|     B     |    H     |terminated|   bla    |    bla    |

|     A     |    I     |requested |   bla    |    bla    | 
|     B     |    I     |requested |   bla    |    bla    | 
|     B     |    K     |requested |   bla    |    bla    |

|     A     |    L     | in test  |   bla    |    bla    |  
|     B     |    L     | in test  |   bla    |    bla    |
|     B     |    M     | in test  |   bla    |    bla    |

Answer 1

您可以将lessThen函数添加到您的类/结构中，然后根据需要为qSort创建转发器。例如：

class m_User {
public:
bool operator<(const m_User other) const {
        return a<other.a;
    }
};

template <typename T>
struct ForwardLessThen
{     
  bool operator()(const T* a, const T* b) const     
  {
    return *a < *b;
  } 
}; 

qSort(list.begin(), list.end(), ForwardLessThen<m_User>());

如果你使用C ++ 11/14，你可以使用lambdas

QList<const m_User*> l;
qSort(l.begin(), l.end(), 
      [](const m_User* a, const m_User* b) -> bool { return a->firstName() < b->firstName(); //implement your logic here
});

使用Qt5 qSort实际上已弃用，您应该使用std :: sort函数。

std::sort(container.begin(), container.end(), qLess<T>());

在QtAlgorithms

中查看基于模板的算法

编辑：或者，如果您计划使用某种视图模型（如ListView），您甚至可以实现自己的QSortFilterProxyModel

Answer 2

    bool compareUsers(const m_User &u1, const m_User &u2)
    {
        if(u1.status != u2.status)
        {
            //compare all possible combination if statuses of the
            //u1 user and u2 user and return which has priority

            //example activated has priorty over terminated
            if(u1.status == "activated" && u2.status =="terminated")
            {
                return true;
            }
            else if(u1.status == "terminated" && u2.status =="activated")
            {
                return false;
            }
            ...
            ..
            .
        }
        else if(u1.firstName != u2.firstName)
        {
            return u1.firstName > u2.firstName;
        }
        else
        {
           return u1.lastName > u2.lastName; 
        }
    }

然后只需在sort函数中调用谓词

QList<m_User> list;
qSort(list.begin(), list.end(), compareUsers);

如何根据特定顺序（不是按字母顺序）对QList进行排序？

2 个答案: