QTreeView - QStyledItemDelegate question

[Lati]

Hei,

I create buttons in QTreeView cells using the code:
Header:

class ButtonDelegateTableView : public QStyledItemDelegate{
    Q_OBJECT

public:
    explicit ButtonDelegateTableView(QObject* parent = Q_NULLPTR,
                                     Project *currentProject = new Project())
        ;QStyledItemDelegate(parent);

    void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE;

    QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE;

    QWidget* createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE;

    void setEditorData(QWidget *editor, const QModelIndex &index) const Q_DECL_OVERRIDE;

    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const Q_DECL_OVERRIDE;

    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE;

    // vars
    Project *_currentProject;
};

.cpp:

ButtonDelegateTableView::ButtonDelegateTableView(QObject* parent,
                                                 Project *currentProject) : QStyledItemDelegate(parent)
{
    _currentProject = currentProject;
}

//ButtonDelegateTableView::~ButtonDelegateTableView(){};

void ButtonDelegateTableView::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
//        Q_ASSERT(index.isValid());
    QStyleOptionViewItem opt = option;
    initStyleOption(&opt, index);
    const QWidget *widget = option.widget;
    QStyle *style = widget ? widget->style() : QApplication::style();
    style->drawControl(QStyle::CE_ItemViewItem, &opt, painter, widget);

    QStyleOptionButton editButtonOption;
    editButtonOption.text = QString("Add"); 
    editButtonOption.rect = QRect(option.rect.left()+option.rect.width()-(option.rect.height()),option.rect.top(),option.rect.height(),option.rect.height());
    editButtonOption.features = QStyleOptionButton::None;
    editButtonOption.direction = option.direction;
    editButtonOption.fontMetrics = option.fontMetrics;
    editButtonOption.palette = option.palette;
    editButtonOption.styleObject = option.styleObject;
    //
    style->drawControl(QStyle::CE_PushButton, &editButtonOption, painter, widget);

}

QSize ButtonDelegateTableView::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    const QSize baseSize = QStyledItemDelegate::sizeHint(option,index);
    return QSize(baseSize.width()+(2*baseSize.height()),baseSize.height());
}

QWidget* ButtonDelegateTableView::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QWidget* result = new QWidget(parent);
    result->setGeometry(option.rect);
    QWidget* baseEditor = QStyledItemDelegate::createEditor(result,option,index);
    baseEditor->setObjectName("baseEditor");
    baseEditor->setGeometry(0,0,option.rect.width()-(option.rect.height()),option.rect.height());
    QPushButton* editButton = new QPushButton("Add", result);
    editButton->setObjectName("editButton");
    editButton->setGeometry(option.rect.width()-(option.rect.height()), 0, option.rect.height(),option.rect.height());
    editButton->setToolTip("Add/edit");

    return result;
}

void ButtonDelegateTableView::setEditorData(QWidget *editor, const QModelIndex &index) const
{
    QWidget* baseEditor = editor->findChild<QWidget*>("baseEditor");
    Q_ASSERT(baseEditor);
    QStyledItemDelegate::setEditorData(baseEditor,index);
}
void ButtonDelegateTableView::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
    QWidget* baseEditor = editor->findChild<QWidget*>("baseEditor");
    Q_ASSERT(baseEditor);
    QStyledItemDelegate::setModelData(baseEditor,model,index);
}
void ButtonDelegateTableView::updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    Q_UNUSED(index)
    editor->setGeometry(option.rect);
    QWidget* baseEditor = editor->findChild<QWidget*>("baseEditor");
    Q_ASSERT(baseEditor);
    baseEditor->setGeometry(0,0,option.rect.width()-(option.rect.height()),option.rect.height());
    QWidget* editButton = editor->findChild<QWidget*>("editButton");
    Q_ASSERT(editButton);
    editButton->setGeometry(option.rect.width()-(option.rect.height()), 0, option.rect.height(),option.rect.height());

    editor->setGeometry(option.rect);
}

And the resulting table looks like this:

My question: How will I know the row number of the clicked "Add" button?
The current code gives me all the time the last row number when I click on any "Add" button.

Thanks for your responses in advance ! :)

[SGaist]

Hi,

How do you get the information currently ?

The index parameter does give you that from a delegate point of view.

[Lati]

@SGaist Thanks for your response.

What I did so far is to pass the parameters to the delegate constructor and that was the reason obviously. I didn't think about the index to get the row number (I didn't know it though :)).

Now I have another issue. How can I connect the buttons to a slot? I tried to connect within the createEditor function like following:

QWidget* ButtonDelegateTableView::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QWidget* result = new QWidget(parent);
    result->setGeometry(option.rect);
    QWidget* baseEditor = QStyledItemDelegate::createEditor(result,option,index);
    baseEditor->setObjectName("baseEditor");
    baseEditor->setGeometry(0,0,option.rect.width()-(option.rect.height()),option.rect.height());
    QPushButton* editButton = new QPushButton("Add", result);
    editButton->setObjectName("editButton");
    editButton->setGeometry(option.rect.width()-(option.rect.height()), 0, option.rect.height(),option.rect.height());
    editButton->setToolTip("Add/edit intervals");

    connect(editButton, SIGNAL(clicked()), this, SLOT(pushButtonCallback(_currentProject, index.row(), _setupIndex)));

    return result;
}

But no chance to call the pushButtonCallback when I click on a button.

[VRonin]

connect(editButton, &QPushButton::clicked, this, std::bind(&ButtonDelegateTableView::pushButtonCallback, this, _currentProject, index.row(), _setupIndex));

[Lati]

@VRonin Thanks VRonin. But I got following 2 errors with your connect script:

• C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits:1468: error: C2672: 'std::invoke': no matching overloaded function found

• C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits:1468: error: C2893: Failed to specialize function template 'unknown-type std::invoke(_Callable &&,_Types &&...)'

Is it related to the slot function definition? It is as following:

void ButtonDelegateTableView::pushButtonCallback(Project *currentProject, int rowNumber, int setupIndex)

[VRonin]

you probably just forgot to #include <functional>

[Lati]

@VRonin Yes, I forgot to add that (I didn't know it to be honest :))

It is added but I still get the same errors.

[VRonin]

is ButtonDelegateTableView::pushButtonCallback overloaded?

[Lati]

@VRonin Nope. I also tested it without any arguments as following and still have the same error:

connect(editButton, &QPushButton::clicked, this, std::bind(&ButtonDelegateTableView::pushButtonCallback, this));

void ButtonDelegateTableView::pushButtonCallback()

[Lati]

@VRonin I made it run using following lambda expression:

    connect(editButton, &QPushButton::clicked, [=]()
    {
       pushButtonCallback( _currentProject, index.row(), _setupIndex);
    } );

Thanks for your response anyway.