Qt MVC Pattern and std::string - qt

Question

My question about model in Qt MVC pattern and std::string type.
For example, i have an object of struct generated from other library (boost, for example):
struct Foo{
int age;
std::string name;
}
And QAbstractListModel data implementation
QVariant FooListModel::data(const QModelIndex &index, int role) const
{
if (index.row() < 0 || index.row() > fooList.count())
return QVariant();
const Foo & foo = contacts[fooList.row()];
if (role == AgeRole) //AgeRole = 0
return foo.age;
else if (role == NameRole) //NameRole = 1
return QString::fromStdString(foo.name);
return QVariant();
}
The problem is that name data doesn't work. Now i see only one solution - convert all Foo class objects to FooQt objects:
struct FooQt{
int age;
QString name;
}
Is there a more clean solution?

Answer 1

The problem is with your usage of Qt's View model. The roles describe differnet aspects of a single item, like displayed text, font, color, decoration, etc.
Your AgeRole (which is 0) equals Qt::DisplayRole. That's why the age seems to work. Your NameRole (which is 1) equals Qt::DecorationRole. You would use that to specify an icon or background color.
You probably want to provide the data for different columns of your model:
QVariant FooListModel::data(const QModelIndex &index, int role) const
{
// Only provide data for valid indices and display role
if (index.row() < 0 || index.row() >= fooList.count() || role != Qt::DisplayRole)
return QVariant();
const Foo & foo = contacts[index.row()];
// Check which column to display
if (index.column() == AgeRole) //AgeRole = 0
return foo.age;
else if (index.column() == NameRole) //NameRole = 1
return QString::fromStdString(foo.name);
return QVariant();
}