Using list model in C++ code with UI in QML

[wysota]

And the problem is...?

Hint: There is an example in examples/declarative/modelviews that shows you how to use a c++ model with qml.

Another hint: ListView is a single column view.

[delor]

And the problem is...?

...that it can't reference variables firstname and lastName.

Another hint: ListView is a single column view.

What does this have to do with my example?

[wysota]

...that it can't reference variables firstname and lastName.

What does this have to do with my example?

Exactly that. It can't reference those variables because you think that settng header names for model columns implicitly binds them with QML variables which is not the case. You can only accessroles of a single column from within Qt Quick's ListView element and you have to tell QtQuick what the roles are called. To use a multicolumn model with ListView you need a proxy model that will turn single role multiple column model into single column multiple role model.

[delor]

How about this then:

// addressbook.cpp
AddressBook::AddressBook(QObject *parent) :
    QSqlQueryModel(parent)
{
    setQuery("select * from person");
 
    QHash<int, QByteArray> roles;
    roles[FirstName] = "firstName";
    roles[LastName] = "lastName";
    setRoleNames(roles);
}
 
QVariant AddressBook::data(const QModelIndex &item, int role) const
{
    QSqlRecord *r = reinterpret_cast<QSqlRecord*>(item.internalPointer());
 
    if (role == FirstName)
        return r->field("firstname").value();
    if (role == LastName)
        return r->field("lastName").value();
    return QVariant();
}

// addressbook.cpp
AddressBook::AddressBook(QObject *parent) :
    QSqlQueryModel(parent)
{
    setQuery("select * from person");

    QHash<int, QByteArray> roles;
    roles[FirstName] = "firstName";
    roles[LastName] = "lastName";
    setRoleNames(roles);
}

QVariant AddressBook::data(const QModelIndex &item, int role) const
{
    QSqlRecord *r = reinterpret_cast<QSqlRecord*>(item.internalPointer());

    if (role == FirstName)
        return r->field("firstname").value();
    if (role == LastName)
        return r->field("lastName").value();
    return QVariant();
}

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item.internalPointer() returns null pointer all the time.

[wysota]

Why would it return a valid QSqlRecord pointer?

[delor]

This worked out just fine:

QVariant AddressBook::data(const QModelIndex &item, int role) const
{
    switch (role) {
    case FirstName:
        return record(item.row()).field("firstname").value();
        break;
    case LastName:
        return record(item.row()).field("lastName").value();
        break;
    default:
        return QSqlQueryModel::data(item, role);
        break;
    }
}

QVariant AddressBook::data(const QModelIndex &item, int role) const
{
    switch (role) {
    case FirstName:
        return record(item.row()).field("firstname").value();
        break;
    case LastName:
        return record(item.row()).field("lastName").value();
        break;
    default:
        return QSqlQueryModel::data(item, role);
        break;
    }
}

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[wysota]

I made a quick implementation of a general way to solve this situation:

[wiki]QMLifyProxyModel[/wiki]

[nouch64]

Hi,

QMLifyProxyModel works quite good for me.
Just one bug correction on it :

The function QMLifyProxyModel::rowCount is actually returning columnCount.
Need to modify it :

int QMLifyProxyModel::rowCount(const QModelIndex &parent) const
{
    if(!sourceModel())
        return 0;
    if(parent.isValid())
        return 0;
 
    return sourceModel()->rowCount();
}

int QMLifyProxyModel::rowCount(const QModelIndex &parent) const
{
    if(!sourceModel())
        return 0;
    if(parent.isValid())
        return 0;

    return sourceModel()->rowCount();
}

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[olegdim]

can you show all structure of connection list model in C++ code with UI in QML???
thanks
i have the same issue

[nouch64]

can you show all structure of connection list model in C++ code with UI in QML???

Sorry, I don't have it anymore, it was in my previous company one year ago.