Qt rightclick QPushButton

问题:

I'm using Qt Creator to create a gui for a mineseeper game. How can I know a QpushButton clicked with rightclick? for flag in the game. In other word, which signal used for rightclick?

回答1:

Create your own button with filter at mousePressEvent slot.

qrightclickbutton.h

#ifndef QRIGHTCLICKBUTTON_H
#define QRIGHTCLICKBUTTON_H

#include <QPushButton>
#include <QMouseEvent>

class QRightClickButton : public QPushButton
{
    Q_OBJECT

public:
    explicit QRightClickButton(QWidget *parent = 0);

private slots:
    void mousePressEvent(QMouseEvent *e);

signals:
    void rightClicked();

public slots:

};

#endif // QRIGHTCLICKBUTTON_H

qrightclickbutton.cpp

#include "qrightclickbutton.h"

QRightClickButton::QRightClickButton(QWidget *parent) :
    QPushButton(parent)
{
}

void QRightClickButton::mousePressEvent(QMouseEvent *e)
{
    if(e->button()==Qt::RightButton)
        emit rightClicked();
}

Now connect like this

QRightClickButton *button = new QRightClickButton(this);
ui->gridLayout->addWidget(button);
connect(button, SIGNAL(rightClicked()), this, SLOT(onRightClicked()));

Create a slot in MainWindow.cpp.

void MainWindow::onRightClicked()
{
    qDebug() << "User right clicked me";
}

It works for me!

回答2:

I think QPushButton is internally implemented to listen to left mouse clicks only. But you can easily extend QPushButton and re-implement let's say the mouse release event and do your thing if the right mouse button was pressed, e.g. emit a custom rightClicked() signal for example:

signals:
    void rightClicked();

protected:
    void mouseReleaseEvent(QMouseEvent *e) {
        if (e->button() == Qt::RightButton) emit rightClicked();
        else if (e->button() == Qt::LeftButton) emit clicked();
    }

... or you can create an overload of the clicked signal that forwards the mouseEvent pointer so you can do the same check outside of the button.

signals:
    void clicked(QMouseEvent *);

protected:
    void mouseReleaseEvent(QMouseEvent *e) {
        emit clicked(e);
    }

Then you do the check in the slot you connect the button's clicked(QMouseEvent *) signal to and proceed accordingly.

回答3:

I just wrote this little helper adapter to make any existing button right-clickable with no need to subclass it:

class CRightClickEnabler : public QObject
{
public:
    CRightClickEnabler(QAbstractButton * button): QObject(button), _button(button) {
        button->installEventFilter(this);
    };

protected:
    inline bool eventFilter(QObject *watched, QEvent *event) override {
        if (event->type() == QEvent::MouseButtonPress)
        {
            auto mouseEvent = (QMouseEvent*)event;
            if (mouseEvent->button() == Qt::RightButton)
                _button->click();
        }
        return false;
    }

private:
    QAbstractButton* _button;
};

Usage:

connect(ui->pushButton, &QPushButton::clicked, [](){qDebug() << "Button clicked";});
new CRightClickEnabler(ui->pushButton);

From now on, the clicked signal will be triggered by the right click as well as left click. There's no need to delete this object - it uses ui->pushButton as parent and will be auto-deleted by Qt when the parent is destroyed.

Obviously, you can write 2 lines of code (literally) to declare a new signal here and emit that signal upon right click instead of clicked, if desired.