How to Initialise Static QMap?

[ChrisW67]

Hi All,

I'm hoping this is not too obvious a question. A static QList can be initialised outside of any method:

class A {
public:
  A();
  ...
private:
  static QList<int> m_list;
  static QMap<int,QString> m_map;
  ...
}

class A {
public:
  A();
  ...
private:
  static QList<int> m_list;
  static QMap<int,QString> m_map;
  ...
}

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and in the cpp file

A::A() { }
...
QList<int> A::m_list = QList<int>() << 1 << 2 << 4;
...

A::A() { }
...
QList<int> A::m_list = QList<int>() << 1 << 2 << 4;
...

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but I cannot see a similar way to initialise the QMap. Can it be done or is it a job for the constructor?

Regards,
Chris W

[boudie]

You have to do something like this:

m_map.insert(1, "Yo");
m_map.insert(2, "Yes");

m_map.insert(1, "Yo");
m_map.insert(2, "Yes");

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[ChrisW67]

Thanks boudie. That way of loading the map would have to happen inside the class constructor or a method.

[rawfool]

@ ChrisW67, Did you figure it out how it's done ? I bumped here while searching for the same.
Thank you.

[Santosh Reddy]

One way is to write a custom class to do so, but yes it is not obvious

// file.h
template <typename Key, typename Value>
class Map : public QMap<Key, Value>
{
public:
    Map() : QMap<Key, Value>() { }
 
    Map<Key, Value>& operator()(const Key & key, const Value & value)
    {
        this->insert(key, value);
        return *this;
    }
};
 
class A
{
public:
    A()
    {
        qDebug() << m_list;
        qDebug() << m_map;
    }
private:
    static QList<int> m_list;
    static QMap<int, QString> m_map;
};
 
// file.cpp file
QList<int> A::m_list = QList<int>() << 1 << 2 << 4;
QMap<int, QString> A::m_map = Map<int, QString>()(1, QString("1"))(2, QString("2"))(4, QString("4"));

// file.h
template <typename Key, typename Value>
class Map : public QMap<Key, Value>
{
public:
    Map() : QMap<Key, Value>() { }

    Map<Key, Value>& operator()(const Key & key, const Value & value)
    {
        this->insert(key, value);
        return *this;
    }
};

class A
{
public:
    A()
    {
        qDebug() << m_list;
        qDebug() << m_map;
    }
private:
    static QList<int> m_list;
    static QMap<int, QString> m_map;
};

// file.cpp file
QList<int> A::m_list = QList<int>() << 1 << 2 << 4;
QMap<int, QString> A::m_map = Map<int, QString>()(1, QString("1"))(2, QString("2"))(4, QString("4"));

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You could also do it with << operator.