Custom context menu event not being caught for QToolButton

[Terrence Mitchem]

I'm working with VS2022 and the official Qt extension

I'm obviously doing something wrong connecting signals and slots. I would expect a right-click on the button to wind up in ShowContextMenu().

Header file:

#pragma once

#include <QtWidgets/QMainWindow>
#include <QtWidgets/QMenu.h>
#include "ui_QtLauncher.h"

QT_BEGIN_NAMESPACE
namespace Ui { class QtLauncherClass; };
QT_END_NAMESPACE

class QtLauncher : public QMainWindow
{
    Q_OBJECT

public:
    QtLauncher(QWidget *parent = nullptr);
    ~QtLauncher();

    void ConfigureUI();
    void ShowContextMenu(const QPoint&);

private:
    Ui::QtLauncherClass *ui;
};

Source file:

#include "stdafx.h"
#include "QtLauncher.h"

/*
#include <string>

using namespace std;
*/

QtLauncher::QtLauncher(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::QtLauncherClass())
{
    ui->setupUi(this);
}

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

void QtLauncher::ConfigureUI()
{
    // Borderless window
    setWindowFlags(Qt::Window | Qt::FramelessWindowHint);

    // Use a background bitmap
    QPixmap bkgnd("Images/background-01.jpg");
    bkgnd = bkgnd.scaled(size(), Qt::IgnoreAspectRatio);
    QPalette palette;
    palette.setBrush(QPalette::Window, bkgnd);
    setPalette(palette);

    // Make the settings button transparent and place text
    ui->SettingsButton->setStyleSheet("QToolButton { background - color: transparent; border: none; }");
    ui->SettingsButton->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);
    
    // Use custom context menu for settings button
    ui->SettingsButton->setContextMenuPolicy(Qt::CustomContextMenu);
    connect(ui->SettingsButton, SIGNAL(customContextMenuRequested(const QPoint&)), ui->SettingsButton, SLOT(ShowContextMenu(const QPoint&)));

    return;
}


void QtLauncher::ShowContextMenu(const QPoint& p)
{
    QMenu myMenu(ui->SettingsButton);
    myMenu.addAction("Menu Item 1");

    myMenu.show();

    return;
}

I'm not sure where I'm messing up.

[Christian Ehrlicher]

@Terrence-Mitchem said in Custom context menu event not being caught for QToolButton:

I'm not sure where I'm messing up.

connect(ui->SettingsButton, SIGNAL(customContextMenuRequested(const QPoint&)), ui->SettingsButton, SLOT(ShowContextMenu(const QPoint&)));

Your connect (the receiver) is wrong. You should use the pmf-style connect syntax to catch such errors.

[Terrence Mitchem]

@Christian-Ehrlicher said in Custom context menu event not being caught for QToolButton:

@Terrence-Mitchem said in Custom context menu event not being caught for QToolButton:

I'm not sure where I'm messing up.

connect(ui->SettingsButton, SIGNAL(customContextMenuRequested(const QPoint&)), ui->SettingsButton, SLOT(ShowContextMenu(const QPoint&)));

Your connect (the receiver) is wrong. You should use the pmf-style connect syntax to catch such errors.

The functor approach seems to have worked seems to have worked:

connect(ui->SettingsButton, &QPushButton::customContextMenuRequested, [=] { ShowContextMenu(ui->SettingsButton); });

Thanks for the pointer, since it lead me to the functor thing!

[Christian Ehrlicher]

@Terrence-Mitchem Why do you use a lambda here? It's not needed.

[SimonSchroeder]

Starting from the old syntax, you should have written

connect(ui->SettingsButton, SIGNAL(customContextMenuRequested(const QPoint&)), this, SLOT(ShowContextMenu(const QPoint&)));

Because ShowContextMenu is a member function of QtLauncher. Somewhere in the output (when running the application) you should have seen that this connect didn't work.

With the new syntax this becomes

connect(ui->SettingsButton, &QToolButton::customContextMenuRequested, this, &QtLauncher::ShowContextMenu);

If you try to put in ui->SettingsButton instead of this, the compiler will complain immediately. By writing it out, hopefully you see that the slot is from the class QtLauncher and thus needs an object of this types.

Unless you have other changes in your code, your current solution should not work. You showed that ShowContextMenu expects a QPoint. However, you are now handing it a QToolButton. Try to connect directly if lambdas are not totally necessary.