QToolTip::showText doesn't work in GraphicsView click handler

[huderlem]

I want to show a tooltip whenever the user clicks on a QGraphicsView widget. To expose a click handler, I have created the following subclass of QGraphicsView called ClickableGraphicsView :

class ClickableGraphicsView : public QGraphicsView
{
    Q_OBJECT
public:
    ClickableGraphicsView() : QGraphicsView() {}
    ClickableGraphicsView(QWidget *parent) : QGraphicsView(parent) {}

public:
    void mousePressEvent(QMouseEvent *event) {
        QGraphicsView::mousePressEvent(event);
        emit this->clicked(event);
    }
    void mouseDoubleClickEvent(QMouseEvent *event) {
        QGraphicsView::mouseDoubleClickEvent(event);
        emit this->clicked(event);
    }

signals:
    void clicked(QMouseEvent *event);
};

This seems to work great--I can successfully hook into the clicked signal. However, the tooltip does not appear anywhere.

QObject::connect(myClickableGraphicsView, &ClickableGraphicsView::clicked, [=](){
    // This is called successfully, logic runs fine.
    DoStuff();

    // This doesn't work!
    QToolTip::showText(QPoint(0, 0), "This doesn't work...");
});

When I setup the exact same code, but for a QPushButton, the tooltip does show up in the top-left corner, as expected.

QObject::connect(myPushButton, &QPushButton::clicked, [=](){
    QToolTip::showText(QPoint(0, 0), "This works!");
}

I tried some other techniques, like emitting a signal from these click handlers, but the same issue persists. I'm a bit out of ideas now. Is there something inherent about a QGraphicsView's event-handling system that would get in the way of the tooltip? Thanks!

[huderlem]

Bumping this, since I haven't received a response, yet.

[SGaist]

Hi,

Can you provide a minimal compilable example ?
By the way, which Qt version and OS are you using ?

[mrjj]

Hi
Make sure you emit Clicked in Release event not pressEvent as that seems to not work as expected.

#include <QMouseEvent>
#include <qgraphicsview.h>
#include <qgraphicsscene.h>
#include <QToolTip>
#include <QGraphicsView>

class MyGraphicsView : public QGraphicsView
{
    Q_OBJECT
public:
    MyGraphicsView(QWidget *parent = nullptr) : QGraphicsView(parent) { }
    void mouseReleaseEvent(QMouseEvent *pMouseEvent) override
    {
        QGraphicsView::mouseReleaseEvent(pMouseEvent);
        emit clicked();
    }
signals:
    void clicked();
};

-- usage ---
  QObject::connect(  ui->graphicsView, &MyGraphicsView::clicked, [this]() {
        QToolTip::showText( ui->graphicsView->mapToGlobal(QPoint(0, 0)),
                            "This doesn't work...");
    });

note the mapToGlobal

result

[huderlem]

@mrjj Thanks--this works perfectly and resolves my issue.