Qt Creator, C++, mouse over function

I want to change the color of an ellipse when I move my mouse over it. But I haven't found anything from reference and auto-complete from Qt Creator.

Do you guys know how to do it?

Some of my code:

void DrawingWidget::paintEvent(QPaintEvent *event) {
    QPainter painter(this);
    painter.fillRect(event->rect(), Qt::white);

    for(int i = 0; i < pointList.size(); i++) {
       开发者_Python百科 if (pointList[i].x() >= 0 && pointList[i].y() >= 0)
            painter.drawEllipse(pointList[i], 10, 10);
    }
    painter.drawLines(lineList);
    m_mainWindow->updateCount();
}

Mouse press event handler:

void DrawingWidget::mousePressEvent(QMouseEvent *event) {
    if (event->button() == Qt::LeftButton
        && event->buttons() == Qt::LeftButton) {
        // DO STUFFF
    }
}

Mouse move event handler:

void DrawingWidget::mouseMoveEvent(QMouseEvent *event) {
    if (m_mainWindow->getSelectedTool() == MainWindow::moveVertexTool) {
        m_x = event->x();
        m_y = event->y();
        if (isPointNear(m_x, m_y)) {
            //STUFF
        }
            update();
        }
    }
}

Now I just need a mouse OVER event (handler).

I think what you are looking for are enter and leave events.

Use QWidget::underMouse() for check if the widget is under the mouse cursor.

For example:

void IconButton::paintEvent(QPaintEvent *)
{
    QPainter painter(this);

    // Note isDown should really use the active state but in most styles
    // this has no proper feedback
    QIcon::Mode mode = QIcon::Disabled;
    if (isEnabled()) {
        if (isDown())
            mode = QIcon::Selected;
        else
            mode = underMouse() ? QIcon::Active : QIcon::Normal;
    }
    QPixmap pixmap = icon().pixmap(iconSize(), mode);

    QRect pixmapRect = QRect(0, 0, pixmap.width(), pixmap.height());
    pixmapRect.moveCenter(rect().center());

    if (m_autoHide)
        painter.setOpacity(m_iconOpacity);

    painter.drawPixmap(pixmapRect, pixmap);
}

This value is not updated properly during drag and drop operations.