用qt写一个圆形的自定义按钮

以下是用Qt编写圆形自定义按钮的示例代码：

circlebutton.h

#ifndef CIRCLEBUTTON_H
#define CIRCLEBUTTON_H

#include <QWidget>
#include <QPainter>
#include <QMouseEvent>

class CircleButton : public QWidget
{
    Q_OBJECT
public:
    explicit CircleButton(QWidget *parent = nullptr);

    QSize sizeHint() const override;

protected:
    void paintEvent(QPaintEvent *event) override;
    void mousePressEvent(QMouseEvent *event) override;
    void mouseReleaseEvent(QMouseEvent *event) override;
    void enterEvent(QEvent *event) override;
    void leaveEvent(QEvent *event) override;

signals:
    void clicked();

private:
    bool m_pressed;
};

#endif // CIRCLEBUTTON_H

circlebutton.cpp

#include "circlebutton.h"

CircleButton::CircleButton(QWidget *parent) : QWidget(parent), m_pressed(false)
{
    setFixedSize(50, 50);
}

QSize CircleButton::sizeHint() const
{
    return QSize(50, 50);
}

void CircleButton::paintEvent(QPaintEvent *event)
{
    Q_UNUSED(event);

    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing, true);

    QColor bgColor = m_pressed ? Qt::lightGray : Qt::white;
    QColor borderColor = m_pressed ? Qt::gray : Qt::black;
    QColor textColor = m_pressed ? Qt::white : Qt::black;

    painter.setBrush(bgColor);
    painter.setPen(borderColor);
    painter.drawEllipse(rect().adjusted(1, 1, -1, -1));

    painter.setPen(textColor);
    painter.drawText(rect(), Qt::AlignCenter, "Button");
}

void CircleButton::mousePressEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton)
    {
        m_pressed = true;
        update();
    }
}

void CircleButton::mouseReleaseEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton)
    {
        if (m_pressed)
        {
            m_pressed = false;
            update();
            emit clicked();
        }
    }
}

void CircleButton::enterEvent(QEvent *event)
{
    Q_UNUSED(event);
    setCursor(Qt::PointingHandCursor);
}

void CircleButton::leaveEvent(QEvent *event)
{
    Q_UNUSED(event);
    unsetCursor();
}

使用方法：

在需要使用圆形按钮的窗口中，添加以下代码：

CircleButton *button = new CircleButton(this);
connect(button, &CircleButton::clicked, [=](){
    // 点击按钮后执行的代码
});

示例效果：