How can I add custom widget to QListView?

[BushyAxis793]

Hello. I have added a QListWidget in the main window of my program. I then created a class that inherits from QWidget. Using a separate dialog box, I created new objects and added them to QListWidget. Everything was fine until I realised that when I tried to change the order of the elements in QListWidget, the contents of the individual elements were being deleted. I did some research on the internet and found that in order to create a list of widgets that I would want to edit (reorder) to some extent, it was best to use QListView + Model/View + Delegate.

I checked out this example: https://doc.qt.io/qt-6/qtwidgets-itemviews-stardelegate-example.html

Unfortunately I didn't understand too much from it. I created my own (working) model and delegate,but I still don't know how to draw my widget. Below the model and delegate:

model.h

#ifndef OPERATIONWIDGETMODEL_H
#define OPERATIONWIDGETMODEL_H

#include <QAbstractItemModel>

class OperationWidgetModel : public QAbstractItemModel
{
    Q_OBJECT
public:
   explicit OperationWidgetModel(QObject *parent = nullptr);

    QVariant data(const QModelIndex &index, int role) const override;
    QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const override;
    QModelIndex parent(const QModelIndex &index) const override;
    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
    int columnCount(const QModelIndex &parent = QModelIndex()) const override;

};

#endif // OPERATIONWIDGETMODEL_H

model.cpp

#include "operationwidgetmodel.h"

OperationWidgetModel::OperationWidgetModel(QObject *parent) : QAbstractItemModel(parent)
{
    //
}

QVariant OperationWidgetModel::data(const QModelIndex &index, int role) const
{
    return QVariant();
}


QModelIndex OperationWidgetModel::index(int row, int column, const QModelIndex &parent) const
{
    QModelIndex index;

    index = createIndex(row,column,nullptr);
    return index;
}

QModelIndex OperationWidgetModel::parent(const QModelIndex &index) const
{
    return QModelIndex();
}

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

    return 1;
}

int OperationWidgetModel::columnCount(const QModelIndex &parent) const
{
    if(parent.isValid()) return 0;
    return 1;
}

delegate.h

#ifndef OPERATIONWIDGETDELEGATE_H
#define OPERATIONWIDGETDELEGATE_H

#include <QStyledItemDelegate>
#include "operationwidget.h"

class OperationWidgetDelegate : public QStyledItemDelegate
{
    Q_OBJECT
public:
    OperationWidgetDelegate(QObject *parent = nullptr);

    void paint(QPainter *painter, const QStyleOptionViewItem &option,
               const QModelIndex &index) const override;
    QSize sizeHint(const QStyleOptionViewItem &option,
                   const QModelIndex &index) const override;
    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,
                          const QModelIndex &index) const override;
    void setEditorData(QWidget *editor, const QModelIndex &index) const override;
    void setModelData(QWidget *editor, QAbstractItemModel *model,
                      const QModelIndex &index) const override;


};

#endif // OPERATIONWIDGETDELEGATE_H

delegate.cpp

#include "operationwidgetdelegate.h"



OperationWidgetDelegate::OperationWidgetDelegate(QObject *parent)
{

}

void OperationWidgetDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{

    QStyledItemDelegate::paint(painter,option,index);
}

QSize OperationWidgetDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{

    OperationWidget widget;

    return QSize(widget.geometry().width(),widget.geometry().height());
}

QWidget *OperationWidgetDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    OperationWidget *widget = new OperationWidget(parent);

    return widget;
}

void OperationWidgetDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
    OperationWidget *widget = qobject_cast<OperationWidget*>(editor);
    if(widget)
    {
        widget->SetOperationName("Cięcie");
    }

}

void OperationWidgetDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
    OperationWidget *widget = qobject_cast<OperationWidget*>(editor);

    if(widget)
    {
        model->setData(index,widget->GetOperationName(),Qt::EditRole);
    }
}

mainwindow.cpp

    OperationWidgetModel *model = new OperationWidgetModel(this);
    ui->listView->setModel(model);
    OperationWidgetDelegate *delegate= new OperationWidgetDelegate(this);
    ui->listView->setItemDelegate(delegate);
    ui->listView->show();

Below is my widget that I want to add to the QListView:

And QListWidget before I started working with QListView:

For any guidance, I would be very grateful.

Have a good day

[mpergand]

@BushyAxis793 said in How can I add custom widget to QListView?:

QRect boundRect = QRect(0,00,275,70);

You must set the origin with option.rect.
Look at the Y position : qDebug()<<option.rect.y();

see an example Here

[JoeCFD]

https://forum.qt.io/topic/93621/add-buttons-in-tablewidget-s-row/10

[SGaist]

Since it's only text that you are showing, you could simply paint them at the correct position. It would make your code simpler and lighter.

[BushyAxis793]

Thanks for the answer. I was able to add the widget to the QListView. But another problem arose. When adding a new item it gets "drawn" in place of the previous one. How do I fix this?

[SGaist]

It's not really clear. Can you show some picture of what is happening ?

[BushyAxis793]

Below I upload the QListView before adding the new item:

After adding the first element, the QListView looks like this:

After adding the second:

Below is my AddItem function:

void OperationWidgetModel::AddItem(OperationWidget *item)
{

    beginInsertRows(QModelIndex(),widgetList.count(),widgetList.count());
    widgetList.append(item);
    endInsertRows();
}

I don't know why, but the next element overlaps the previous one.

[mpergand]

@BushyAxis793
Show your paint() code,
you probably don't use option.rect to get the right position.

[BushyAxis793]

Here is my paint():

void OperationWidgetDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{

    if(!index.isValid())
    {
        return;
    }

    painter->save();

    if(option.state & QStyle::State_Selected)
    {
        painter->fillRect(option.rect,option.palette.highlight());
    }


    OperationWidget* widget = index.data().value<OperationWidget*>();

    QRect boundRect = QRect(0,00,275,70);
    
    painter->setPen(QPen(Qt::black,0.5,Qt::SolidLine));
   
    painter->drawRect(boundRect);

    QRect operationNameRect = QRect(0,10,275,70);
    QRect operationToolsRect =  QRect(10,40,275,70);
    QRect operationTimeRect = QRect(-10,40,275,70);
    QFont bold("Roboto",10);
    bold.setBold(true);
    painter->setFont(bold);
    painter->setPen(Qt::black);

    painter->drawText(operationNameRect,Qt::AlignTop | Qt::AlignHCenter,widget->GetOperationName());
    painter->drawText(operationToolsRect,Qt::AlignLeft,QString::number(widget->GetToolsQuantity())+ " [szt.]");
    painter->drawText(operationTimeRect,Qt::AlignRight,QString::number(widget->GetOperationTime())+ " [min.]");





}

[mpergand]

@BushyAxis793 said in How can I add custom widget to QListView?:

QRect boundRect = QRect(0,00,275,70);

You must set the origin with option.rect.
Look at the Y position : qDebug()<<option.rect.y();

see an example Here

[SGaist]

Beside what @mpergand pointed, are you still using one widget per row ? This is bad design. The proper use of the delegate means you can drop that widget completely.

[BushyAxis793]

@mpergand I think I don't understand. I change my origin for :

QRect boundRect = op.rect;

Now I have the same issue but without border.

[BushyAxis793]

@SGaist To be honest, I ultimately wanted to use QListWidget, but it doesn't have all the features. And I've been struggling with QListView + Model + Delegate for a few weeks now.

[mpergand]

@BushyAxis793

I think you need to implement sizeHint() as well.

As @SGaist noted, your code is confusing :)

Can you post a skech of what you want to do, is it a single list of text cells ?

[BushyAxis793]

Let me describe as simply as I can. I have added a QListWidget in the main window of my program. I created a new class called OperationWidget, which inherits from QWidget. It has all the methods and variables it needs. In an additional QDialog window, I set the parameters of the OperationWidget object and then add it to QListWidget. I can add and remove items from QListWidget, but I cannot change the position of the items. So I have to use QListView + OperationWidgetModel + OperationWidgetDelegate. I have never worked with models and delegates, but I know there is no other way. I want the whole thing to look like the QListWidget.

OperationWidget.h

#ifndef OPERATIONWIDGET_H
#define OPERATIONWIDGET_H

#include <QWidget>

namespace Ui {
class OperationWidget;
}

class OperationWidget : public QWidget
{
    Q_OBJECT

public:
    explicit OperationWidget(QWidget *parent = nullptr);
    ~OperationWidget();

    void SetOperationName(const QString&);
    QString GetOperationName()const;

    void SetWorkplaceName(const QString&);
    QString GetWorkplaceName()const;

    void SetToolQuantity(const int&);
    int GetToolsQuantity()const;

    void SetOperationTime(const double&);
    double GetOperationTime() const;

    void SetOperationDescription(const QString&);
    QString GetOperationDescription()const;

    void SetPreparationAndCompletionTime(const int&);
    int GetPreparationAndCompletionTime()const;

    void SetWorkplaceNumber(const QString&);
    QString GetWorkplaceNumber()const;

    void SetWorkplaceCost(const int&);
    int GetWorkplaceCost()const;

    void SetUnitTime(const int&);
    int GetUnitTime()const;

    void LoadToolTip();

private:
    Ui::OperationWidget *ui;
    QString operationName;
    QString workplaceName;
    int toolsQuantity;
    double operationTime;
    QString operationDescription;
    int preparationAndCompletionTime;
    QString workplaceNumber;
    int workplaceCost;
    int unitTime;

};

#endif // OPERATIONWIDGET_H

OperationWidget.cpp

#include "operationwidget.h"
#include "ui_operationwidget.h"
#include <QFrame>

OperationWidget::OperationWidget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::OperationWidget)
{
    ui->setupUi(this);


}

OperationWidget::~OperationWidget()
{
    delete ui;
}

void OperationWidget::SetOperationName(const QString &name)
{
    operationName = name;
    ui->operationNameLabel->setText(name);
}

QString OperationWidget::GetOperationName() const
{
    return operationName;
}

void OperationWidget::SetWorkplaceName(const QString &name)
{
    workplaceName = name;
}

QString OperationWidget::GetWorkplaceName() const
{
    return workplaceName;
}

void OperationWidget::SetToolQuantity(const int &tools)
{
    toolsQuantity = tools;
    ui->toolsQuantityLabel->setText(QString::number(tools)+ " "+"[szt.]");
}

int OperationWidget::GetToolsQuantity() const
{
    return toolsQuantity;
}

void OperationWidget::SetOperationTime(const double &time)
{
    operationTime = time;
    ui->timeOperationLabel->setText(QString::number(GetOperationTime())+ " "+ "[min.]");
}

double OperationWidget::GetOperationTime() const
{
    return operationTime;
}

void OperationWidget::SetOperationDescription(const QString &description)
{
    operationDescription = description;
}

QString OperationWidget::GetOperationDescription() const
{
    return operationDescription;
}

void OperationWidget::SetPreparationAndCompletionTime(const int &tpz)
{
    preparationAndCompletionTime = tpz;
}

int OperationWidget::GetPreparationAndCompletionTime() const
{
    return preparationAndCompletionTime;
}

void OperationWidget::SetWorkplaceNumber(const QString &number)
{
    workplaceNumber = number;
}

QString OperationWidget::GetWorkplaceNumber() const
{
    return workplaceNumber;
}

void OperationWidget::SetWorkplaceCost(const int &cost)
{
    workplaceCost = cost;
}

int OperationWidget::GetWorkplaceCost() const
{
    return workplaceCost;
}

void OperationWidget::SetUnitTime(const int &unitT)
{
    unitTime = unitT;
}

int OperationWidget::GetUnitTime() const
{
    return unitTime;
}

void OperationWidget::LoadToolTip()
{
    this->setToolTip("Nazwa stanowiska: "+GetWorkplaceName()+"\n"+
                     "Nazwa operacji: "+GetOperationName()+ "\n"+
                     "Numer stanowiska: "+GetWorkplaceNumber()+"\n"+
                     "Koszt stanowiska: "+QString::number(GetWorkplaceCost())+ " [zł]"+"\n"+
                     "Czas przygotowawczy: "+QString::number(GetPreparationAndCompletionTime())+" [min.]"+"\n"+
                     "Czas jednostkowy: "+QString::number(GetUnitTime())+" [min.]"+"\n"+
                     "Ilość narzędzi: "+QString::number(GetToolsQuantity())+"\n"+
                     "Czas operacji: "+QString::number(GetOperationTime())+" [min.]"+"\n"+
                     "Opis operacji: "+GetOperationDescription());
}

QListWidget in mainwindow:

Put simply. I want to add my own widget to the QListView.

[SGaist]

As written in the documentation and here as well: setCellWidget should only be used to show some static content not as a replacement of a properly implemented delegate.

There's no need for that widget of yours unless it's an editor.

You really should take the time to build a proper model to store your data. It will be a table of some sort. Which you can use with a QListView.

Basically, your delegate will have to pull the data from the model when drawing. You will essentially have to position the text properly. There really isn't more to it than that.

[BushyAxis793]

I found the solution. The problem was in paint(). Now it looks much better

Thanks everyone for help!

Unfortunatelly, I found another issue. In slot when I add my widget to list:

void QueriesCreator::ReceiveOperationData(QString workplaceName, QString operationName, int tools, double time, QString description,int tpz, QString number, int cost, int unitT)
{

    OperationWidget* operationWidget = new OperationWidget(new QWidget);

    operationWidget->SetWorkplaceName(workplaceName);
    operationWidget->SetOperationName(operationName);
    operationWidget->SetToolQuantity(tools);
    operationWidget->SetOperationTime(time);
    operationWidget->SetOperationDescription(description);
    operationWidget->SetPreparationAndCompletionTime(tpz);
    operationWidget->SetWorkplaceNumber(number);
    operationWidget->SetWorkplaceCost(cost);
    operationWidget->SetUnitTime(unitT);
    operationWidget->LoadToolTip();

    model.AddItem(operationWidget);
}

As you can see I call LoadToolTip() method:

void OperationWidget::LoadToolTip()
{
    this->setToolTip("Nazwa stanowiska: "+GetWorkplaceName()+"\n"+
                     "Nazwa operacji: "+GetOperationName()+ "\n"+
                     "Numer stanowiska: "+GetWorkplaceNumber()+"\n"+
                     "Koszt stanowiska: "+QString::number(GetWorkplaceCost())+ " [zł]"+"\n"+
                     "Czas przygotowawczy: "+QString::number(GetPreparationAndCompletionTime())+" [min.]"+"\n"+
                     "Czas jednostkowy: "+QString::number(GetUnitTime())+" [min.]"+"\n"+
                     "Ilość narzędzi: "+QString::number(GetToolsQuantity())+"\n"+
                     "Czas operacji: "+QString::number(GetOperationTime())+" [min.]"+"\n"+
                     "Opis operacji: "+GetOperationDescription());
}

But I can see any tooltip when I move cursor over widget. How can I enable it? Any ideas?

[SGaist]

A delegate does not handle tooltips, you should return them through the model for the Qt::ToolTipRole role.