Horizontalheaderview with QSortFilterProxyModel

maxwell31

Hi,

I have a question: I have a QAbstractTableModel which sets the headerData. Then I filter it with QSortFilterProxyModel and in QML I use the QuickControls2 TableView for displaying it, together with a Horizontalheaderview.

The problem: The headers don't get displayed if I put a QSortFilterProxymodel inbetween. If I set the TableView directly to QAbstractTableModel the headers get displayed correct.

From the HorizontalHeaderView documentation:

model is a QAbstractTableModel, its horizontal headerData() will be accessed.

If model is a QAbstractItemModel other than QAbstractTableModel, model's data() will be accessed.

Is it possible that QSortFilterProxyModel makes a QAbstractItemModel out of my tablemodel and therefore it stops working? Or does someone got this working?

maxwell31

Ok, the problem seems to linked to the following from the HorizontalHeaderView documentation:

The header displays data from the {syncView}'s model by default, but can also have its own model. If the model is a QAbstractTableModel, then the header will display the model's horizontal headerData(); otherwise, the model's data().

So the headerData ist not taken, which seems to be a weird default behaviour.

maxwell31

In case someone wants to reproduce this:
headers are displayed correctly if if use tableModel in the qml file, and it stops working if I use sortModel

main.qml

import QtQuick 2.15
import QtQuick.Window 2.15
import Qt.labs.qmlmodels 1.0
import QtQuick.Controls 2.15
Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")
    HorizontalHeaderView {
        id: horizontalHeader
        syncView: tableView
        anchors.left: tableView.left
    }
    VerticalHeaderView {
        id: verticalHeaderView
        syncView: tableView
        anchors.right: tableView.left
        anchors.top: tableView.top
    }
    TableView {

        id: tableView
        anchors.fill: parent
        anchors.margins: 50

        model: sortModel
        delegate: Rectangle {
            width: 30
            height: 30
            border.color: "black"
            Text{
            color: "black"
            text: model.display

            }
        }
    }
}

main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include <QSortFilterProxyModel>

#include "tablemodel.h"
int main(int argc, char *argv[])
{
  QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

  QGuiApplication app(argc, argv);

  QQmlApplicationEngine engine;
  const QUrl url(QStringLiteral("qrc:/main.qml"));
  QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                   &app, [url](QObject *obj, const QUrl &objUrl) {
    if (!obj && url == objUrl)
      QCoreApplication::exit(-1);
  }, Qt::QueuedConnection);

  TableModel tm;
  engine.rootContext()->setContextProperty("tableModel",&tm);
  QSortFilterProxyModel sortModel;
  sortModel.setSourceModel(&tm);
  engine.rootContext()->setContextProperty("sortModel",&sortModel);
  engine.load(url);

  return app.exec();
}

tablemodel.h

#ifndef TABLEMODEL_H
#define TABLEMODEL_H

#include <QAbstractTableModel>

class TableModel : public QAbstractTableModel
{
  Q_OBJECT

public:
  explicit TableModel(QObject *parent = nullptr);

  // Header:
  QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;

  // Basic functionality:
  int rowCount(const QModelIndex &parent = QModelIndex()) const override;
  int columnCount(const QModelIndex &parent = QModelIndex()) const override;

  QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;

private:
};

#endif // TABLEMODEL_H

tablemodel.cpp

#include "tablemodel.h"

TableModel::TableModel(QObject *parent)
  : QAbstractTableModel(parent)
{
}

QVariant TableModel::headerData(int section, Qt::Orientation orientation, int role) const
{
  return section;
}

int TableModel::rowCount(const QModelIndex &parent) const
{
  if (parent.isValid())
    return 0;
 return 5;
}

int TableModel::columnCount(const QModelIndex &parent) const
{
  if (parent.isValid())
    return 0;
  return 7;
}

QVariant TableModel::data(const QModelIndex &index, int role) const
{
  if (!index.isValid())
    return QVariant();
  return QVariant::fromValue(QString::number(index.row())+","+QString::number(index.column()));
}