先介绍一下函数对象

下面直接定义一个用于比较的函数对象类

///file Compare.h
#pragma once
class Person;
enum EnumCompType
{
    ASC,
    DESC,
};

enum EnumCompField
{
    ECF_Name,
    ECF_Phone,
};

class Compare
{
public:
    Compare(EnumCompType etype, EnumCompField eField);
    bool operator() (const Person *, const Person *);
private:
    EnumCompType m_eCompType;
    EnumCompField m_eCompField;
};

///file Compare.cpp
#include "Compare.h"
#include "Person.h"

#include <QLocale>
#include <QCollator>

Compare::Compare(EnumCompType etype, EnumCompField eField)
    :m_eCompType(etype)
    ,m_eCompField(eField)
{
}

bool Compare::operator()(const Person *pP1, const Person *pP2)
{
    QLocale loc(QLocale::Chinese, QLocale::China);
    QCollator qcol(loc);
    int nResult = 0;
    QString str1;
    QString str2;
    switch (m_eCompField)
    {
    case ECF_Name:
        str1 = QString::fromLocal8Bit(pP1->GetName().c_str());
        str1 = QString::fromLocal8Bit(pP2->GetName().c_str());
        break;
    case ECF_Phone:
        str1 = QString::fromLocal8Bit(pP1->GetPhone().c_str());
        str1 = QString::fromLocal8Bit(pP2->GetPhone().c_str());
        break;
    default:
        break;
    }
    nResult = qcol.compare(str1, str2);
    if (ASC == m_eCompType)
        return nResult < 0 ? true : false;
    else
        return nResult < 0 ? false : true;
    return false;
}

其中 Person 定义如下：

///file Person.h
#pragma once
#include <string>
class Person
{
public:
    Person();
    Person(std::string, std::string);
    Person(Person &other);
    ~Person();
    const std::string GetName() const { return m_strName; }
    const std::string GetPhone() const { return m_strPhone; }
private:
    std::string m_strName;
    std::string m_strPhone;
};

///file Person.cpp
#include "Person.h"

Person::Person()
{
}

Person::Person(std::string strName, std::string strPhone)
    :m_strName(strName)
    ,m_strPhone(strPhone)
{
}


Person::Person(Person & other)
{
    this->m_strName = other.m_strName;
    this->m_strPhone = other.m_strPhone;
}

Person::~Person()
{
}

随后对于给定的 QList<Person>,可以直接排序

/// mian.cpp
#include <QtCore/QCoreApplication>
#include "Person.h"
#include "Compare.h"

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QList<Person *> lstPerson;
    Person p1("a", "123456789");
    Person p2("b", "23456789");
    Person p3("c", "3456789");
    Person p4("d", "456789");
    Person p5("e", "56789");
    Person p6("f", "6789");
    Person p7("g", "789");
    Person p8("h", "89");
    Person p9("i", "9");

    lstPerson.append(&p4);
    lstPerson.append(&p6);
    lstPerson.append(&p9);
    lstPerson.append(&p3);
    lstPerson.append(&p7);
    lstPerson.append(&p2);
    lstPerson.append(&p1);
    lstPerson.append(&p5);
    lstPerson.append(&p8);

    auto begin = lstPerson.begin();
    auto end = lstPerson.end();
    //??? Compare 是否会做 插入 或 删除操作 导致 end 失效呢？？？
    qSort(begin, end, Compare(ASC, ECF_Name));
    return a.exec();
}