Questions regarding QAbstractTableModel and QDataWidgetMapper

[BadPistol97]

@SGaist

I found that no matter I put toFirst(), toNext(), or toLast() the LineEdits being mapped by the mapper always contain the data from the first row of the table.

    mapper->setOrientation(Qt::Horizontal);

    mapper->setSubmitPolicy(QDataWidgetMapper::ManualSubmit);

    mapper->setModel(PhoneBookModel);

    connect(
        ui->tableView->selectionModel(),&QItemSelectionModel::currentRowChanged,
                mapper,&QDataWidgetMapper::setCurrentModelIndex);

    mapper->addMapping(ui->lineEdit,0);
    mapper->addMapping(ui->lineEdit_2,1);

    mapper->toLast();

What did I do wrong?

[SGaist]

When are you adding data to your model ?

[BadPistol97]

@SGaist

I added data to the model before the tableView set to that model:

 aModel *PhoneBookModel = new aModel(this);

 PhoneBookModel->setContactsInfo("Thomas","123-456-7890");
 PhoneBookModel->setContactsInfo("Richard","222-333-4444");

 ui->tableView->setModel(PhoneBookModel);
 ui->tableView->horizontalHeader()->setVisible(true);
 ui->tableView->show();

Then I mapped the data of the model to lineEdits.

[VRonin]

Stop. Step back.
It looks like you want 2 labels and 2 line edits for each row in your model. Can I ask why?
You can edit the items directly inside the view, you don't need external editors

[BadPistol97]

@VRonin

I wanted to make something like this:

This is the page showing table

And another view to edit the record, so I would like to have each column of a row mapped to a lineEdit

[SGaist]

Did you already took a look at the Simple Widget Mapper Example ?

[BadPistol97]

@SGaist

I did take a look at it before, but the example uses only 3 widgets for all rows of the table.
I wanted to make the number of widgets flexible:

As in the first card has different number of lineEdits compared to the second card when expanded.

I am thinking of using a different mapper here, set to the same model and map to different widgets:

    PhoneBookModel->setContactsInfo("Thomas","123-456-7890");
    PhoneBookModel->setContactsInfo("Richard","222-333-4444");

    mapper->setModel(PhoneBookModel);

    connect(
        ui->tableView->selectionModel(),&QItemSelectionModel::currentRowChanged,
                mapper,&QDataWidgetMapper::setCurrentModelIndex);

    mapper->addMapping(ui->lineEdit,0);
    mapper->addMapping(ui->lineEdit_2,1);
    mapper->toFirst();
    
    // another mapper
    QDataWidgetMapper *anotherMapper = new QDataWidgetMapper(this);

    anotherMapper->setModel(PhoneBookModel);

    connect(
        ui->tableView->selectionModel(),&QItemSelectionModel::currentRowChanged,
                anotherMapper,&QDataWidgetMapper::setCurrentModelIndex);
    
    // toLast() doesn't work as what I thought it would
    anotherMapper->toLast();
    anotherMapper->addMapping(ui->lineEdit_3,0);
    anotherMapper->addMapping(ui->lineEdit_4,1);

The code above doesn't work as the toLast() doesn't work as what I thought it would; changing the row currently pointing to in a model.

[SGaist]

How do you build these different widgets ?

[BadPistol97]

@SGaist

in UI :

The first two lineEdits are for the first row of the table. The third and fourth are for the second row of the table.

[VRonin]

should be something like:

#include <QLineEdit>
#include <QStyledItemDelegate>
#include <QFormLayout>
#include <QPainter>
#include <QAbstractItemModel>
#include <QRegularExpressionValidator>
class ContactEditor : public QWidget{
    Q_OBJECT
    Q_DISABLE_COPY(ContactEditor)
public:
    explicit ContactEditor(QWidget* parent = nullptr)
        :QWidget(parent)
        , m_nameEdit(new QLineEdit(this))
        , m_phoneEdit(new QLineEdit(this))
    {
        QFormLayout* mainLay = new QFormLayout(this);
        mainLay->addRow(tr("Name"),m_nameEdit);
        mainLay->addRow(tr("Phone"),m_phoneEdit);
        auto phoneValidator = new QRegularExpressionValidator(this);
        phoneValidator->setRegularExpression(QRegularExpression(QStringLiteral("[\\d-]*")));
        m_phoneEdit->setValidator(phoneValidator);
    }

    QString name() const{return  m_nameEdit->text();}
    void setName(const QString& val) {m_nameEdit->setText(val);}
    QString phone() const{return  m_phoneEdit->text();}
    void setPhone(const QString& val) {m_phoneEdit->setText(val);}

private:
    QLineEdit* m_nameEdit;
    QLineEdit* m_phoneEdit;
};
template <class T>
class WidgetDelegate : public QStyledItemDelegate{
#ifdef Q_COMPILER_STATIC_ASSERT
    static_assert(std::is_base_of<QWidget,T>::value,"Template argument must be a QWidget");
#endif
    Q_DISABLE_COPY(WidgetDelegate)
public:
    explicit WidgetDelegate(QObject* parent = Q_NULLPTR)
        :QStyledItemDelegate(parent)
        , m_baseWid(new T)
    {}
    ~WidgetDelegate(){
        delete m_baseWid;
    }
    void paint(QPainter *painter, const QStyleOptionViewItem &option,const QModelIndex &index) const Q_DECL_OVERRIDE{
        setSubEditorData(m_baseWid,index);
        m_baseWid->resize(option.rect.size());
        QPixmap pixmap(option.rect.size());
        m_baseWid->render(&pixmap);
        painter->drawPixmap(option.rect,pixmap);
    }
    QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE{
        Q_UNUSED(option);
        setSubEditorData(m_baseWid,index);
        return m_baseWid->sizeHint();
    }
    QWidget* createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE Q_DECL_FINAL {
        Q_UNUSED(option);
        Q_UNUSED(index);
        T* editor = new T;
        editor->setParent(parent);
        return editor;
    }
    virtual void setSubEditorData(T* editor, const QModelIndex &index) const =0;
    void setEditorData(QWidget* editor, const QModelIndex &index) const Q_DECL_OVERRIDE Q_DECL_FINAL {
        T* subEdit = qobject_cast<T*>(editor);
        Q_ASSERT(subEdit);
        return setSubEditorData(subEdit,index);
    }
private:
    T* m_baseWid;
};

class ContactDelegate : public WidgetDelegate<ContactEditor>{
    Q_DISABLE_COPY(ContactDelegate)
public:
    explicit ContactDelegate(QObject* parent=Q_NULLPTR)
        :WidgetDelegate<ContactEditor>(parent)
    {}
    void setSubEditorData(ContactEditor* editor, const QModelIndex &index) const Q_DECL_OVERRIDE{
        editor->setName( displayText(index.data(),editor->locale()));
        editor->setPhone(displayText(index.data(Qt::UserRole),editor->locale()));
    }
};

and then you can use it in a delegate like:

int main(int argc, char **argv)
{
    QApplication app(argc,argv);
    QListWidget wid;
    wid.setEditTriggers(QAbstractItemView::AllEditTriggers);
    wid.setItemDelegate(new ContactDelegate(&wid));
    wid.model()->insertRows(0,2);
    wid.model()->setData(wid.model()->index(0,0),"Thomas");
    wid.model()->setData(wid.model()->index(0,0),"123456789",Qt::UserRole);
    wid.model()->setData(wid.model()->index(1,0),"Richard");
    wid.model()->setData(wid.model()->index(1,0),"987654321",Qt::UserRole);
    wid.show();
    return app.exec();
}

[BadPistol97]

@VRonin @SGaist

Alright, thanks guys.