Cannot hide QtQuick.TableView columns

patrickkidd

The documentation for TableView suggests using TableView.contentWidthProvider to return 0 to hide columns. However, this is incorrect as the code ignores a width of zero providing some default width, and complains with:

QML TableView: columnWidthProvider did not return a valid width for column: 2

Setting visible: false in the delegate also does not seem to work, even when a valid width (for example 1px) is specified. What is the proper way to hide columns in QtQuick.TableView?

patrickkidd

I put together a simple example to demonstrate this problem and found that TableView does indeed honor columnWidthProvider returning a value of zero, as documented. That means there is a problem in my code.

I'll report back here once I figure it out.

main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include "tablemodel.h"

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QGuiApplication app(argc, argv);
    QQmlApplicationEngine engine;

    qmlRegisterType<TableModel>("TableModel", 1, 0, "TableModel");

    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);

    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"
#include <QtQml>


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

QVariant TableModel::headerData(int section, Qt::Orientation orientation, int role) const
{
    Q_UNUSED(orientation);
    Q_UNUSED(role);
    return QString("Column %1").arg(section);
}

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

    return 100;
}

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

    return 10;
}

QVariant TableModel::data(const QModelIndex &index, int role) const
{
    Q_UNUSED(role);

    if (!index.isValid())
        return QVariant();

    return QString("Cell %1, %2").arg(index.row()).arg(index.column());
}

//qmlRegisterType<TableModel>("com.vedanamedia.TableModel", 1, 0, "TableModel");

main.qml

import QtQuick 2.13
import QtQuick.Window 2.13
import TableModel 1.0

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    TableView {
        anchors.fill: parent
        model: TableModel { }
        columnWidthProvider: function(col) {
            if(col % 2 == 0) {
                return 0;
            } else {
                var nShownColumns = 0
                for(var i=0; i < model.columnCount(); i++) {
                    if(i % 2 != 0) {
                        nShownColumns++;
                    }
                }
                return width / nShownColumns;
            }
        }
        contentWidth: width
        onWidthChanged: {
            if(contentWidth > 0) // prevent crash (Qt bug)
                forceLayout()
        }
        delegate: Rectangle {
            implicitWidth: 100
            implicitHeight: 50
            Text {
                anchors.centerIn: parent
                  text: display
            }
            Rectangle { // border-left
                width: 3
                height: parent.height
                color: 'green'
            }
            Rectangle { // border-right
                width: 3
                height: parent.height
                x: parent.width-3
                color: 'red'
            }
        }
    }
}

patrickkidd

@patrickkidd said in Cannot hide QtQuick.TableView columns:

I put together a simple example to demonstrate this problem and found that TableView does indeed honor columnWidthProvider returning a value of zero, as documented. That means there is a problem in my code.

Aha! This is fixed in Qt-5.13.0. My dev build was using 5.12.4 which is why I was getting the bug. I was running my test example against 5.13.0, which shows that it I fixed.