Set Delegate for each cell in a QTableWidget?

VRonin

Simplified example:

buttondelegate.h

#ifndef BUTTONDELEGATE_H
#define BUTTONDELEGATE_H

#include <QApplication>
#include <QStyledItemDelegate>
#include <QPushButton>
#include <QPainter>

class ButtonDelegate : public QStyledItemDelegate
{
    Q_OBJECT
#if QT_VERSION >= QT_VERSION_CHECK(5, 13, 0)
    Q_DISABLE_COPY_MOVE(ButtonDelegate)
#else
    Q_DISABLE_COPY(ButtonDelegate)
#endif
public:
    explicit ButtonDelegate(QObject* parent)
        :QStyledItemDelegate(parent)
    {

    }
    void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE
    {
        Q_ASSERT(index.isValid());
        QStyleOptionViewItem opt = option;
        initStyleOption(&opt, index);
        const QWidget *widget = option.widget;
        QStyle *style = widget ? widget->style() : QApplication::style();
        QStyleOptionButton buttonOption = buttonOptions(opt,index);
        style->drawControl(QStyle::CE_PushButton, &buttonOption, painter, widget);
    }
    QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE
    {
        QStyleOptionViewItem opt = option;
        initStyleOption(&opt, index);
        return buttonRect(opt).size();
    }
    QWidget* createEditor(QWidget *parent, const QStyleOptionViewItem &, const QModelIndex &) const Q_DECL_OVERRIDE
    {
        return new QWidget(parent);
    }
    void setEditorData(QWidget *, const QModelIndex &) const Q_DECL_OVERRIDE
    {

    }
    void setModelData(QWidget *, QAbstractItemModel *, const QModelIndex &) const Q_DECL_OVERRIDE
    {

    }
    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE
    {
        QStyleOptionViewItem opt = option;
        initStyleOption(&opt, index);
        editor->setGeometry(opt.rect);
        const QRect butRect = buttonRect(opt);
        QWidget* baseEditor = editor->findChild<QWidget*>("baseEditor");
        Q_ASSERT(baseEditor);
        baseEditor->setGeometry(0,0,opt.rect.width()-butRect.width(),opt.rect.height());
        QWidget* myButton = editor->findChild<QWidget*>("myButton");
        Q_ASSERT(myButton);
        myButton->setGeometry(opt.rect.width()-butRect.width(), 0, butRect.width(),butRect.height());
    }
Q_SIGNALS:
    void clicked(const QModelIndex &index);
protected:
    bool editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index) override
    {
        Q_ASSERT(event);
        Q_ASSERT(model);
        Qt::ItemFlags flags = model->flags(index);
        if ((option.state & QStyle::State_Enabled) && (flags & Qt::ItemIsEnabled))
        {
            switch (event->type()){
            case QEvent::MouseButtonRelease:{
                QStyleOptionViewItem viewOpt(option);
                initStyleOption(&viewOpt, index);
                QMouseEvent *me = static_cast<QMouseEvent*>(event);
                if (me->button() == Qt::LeftButton)
                {
                    currentIndex = index;
                    clickedHelper();
                }
            }
                break;
            default:
                break;
            }
        }
        return QStyledItemDelegate::editorEvent(event,model,option,index);
    }
    virtual QStyleOptionButton buttonOptions(const QStyleOptionViewItem &option, const QModelIndex &index, bool skipRct=false) const
    {
        QStyleOptionButton buttonOption;
        buttonOption.icon = m_buttonIcon;
        if(index.data(Qt::UserRole).toBool())
            buttonOption.text = QString(QChar(0x23F8)); //pause button emoji
        else
            buttonOption.text = QString(QChar(0x25B6)); //play button emoji
        buttonOption.rect = skipRct ? QRect() : buttonRect(option);
        buttonOption.features = QStyleOptionButton::None;
        buttonOption.direction = option.direction;
        buttonOption.fontMetrics = option.fontMetrics;
        buttonOption.palette = option.palette;
        buttonOption.styleObject = option.styleObject;
        return buttonOption;
    }
    virtual QRect buttonRect(const QStyleOptionViewItem &option) const
    {
        return option.rect;
    }

private:
    mutable QModelIndex currentIndex;
    QString m_buttonText;
    QIcon m_buttonIcon;
    void clickedHelper()
    {
        clicked(currentIndex);
    }

};
#endif // BUTTONDELEGATE_H

main.cpp

#include <QApplication>
#include <QTableWidget>
#include "buttondelegate.h"

int main(int argc, char *argv[])
{
    QApplication app(argc,argv);
    QTableWidget wid(10,2);
    for(int i=0;i<10;++i){
        wid.setItem(i,0,new QTableWidgetItem(QStringLiteral("Item %1").arg(i+1)));
    }
    ButtonDelegate* buttonDelegate = new ButtonDelegate(&wid);
    QObject::connect(buttonDelegate,&ButtonDelegate::clicked,&wid,[&wid](const QModelIndex& index){
        Q_ASSERT(index.model()==wid.model());
        wid.model()->setData(index,index.data(Qt::UserRole).toBool() ? QVariant() : true,Qt::UserRole);
    });
    wid.setItemDelegateForColumn(1, buttonDelegate);
    wid.show();
    return app.exec();
}

hbatalha

@VRonin This one seems to be the solution I have been looking for. I will, however, have to hack my current code to using this solution. In case of any question I will reach out to you.

Thank you for taking so much time and having so much patience with me. I appreciate it.

hbatalha

@VRonin hi, I have finished modifying the delegate button so I can use it in my code and it works fine.
However, I am wondering how can I set a stylesheet for it. With my old QPushButton I had it like this:

QPushButton* cancel_button = new QPushButton(this);
cancel_button->setIcon(QIcon(QPixmap(":/Icons/cancel.png")));
cancel_button->setStyleSheet("QPushButton{background-color: transparent; background-repeat: none; border: none;}  QPushButton:pressed{ background-color: transparent; }");

Can I do it with the delegate button? The reason I want to do this is because I want the the button to display only the icon I set for it.

Edit: I think I have solved it by going in the QStyleOptionButton buttonOptions(const QStyleOptionViewItem &option, bool skipRct=false) const function and change the QStyleOptionButton features to flat:

        QStyleOptionButton buttonOption;
        buttonOption.features = QStyleOptionButton::Flat;