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.