不解析，直接给代码例子
利用窗口重绘事件处理函数paintEvent
main.cpp
#include <QtCore/qglobal.h>
#if QT_VERSION >= 0x050000
#include <QtWidgets/QApplication>
#else
#include <QtGui/QApplication>
#endif#include "roundedwindow.h"int main(int argc, char *argv[]) {QApplication a(argc, argv);RoundedWindow wnd{};wnd.init();return a.exec();
}roundedwindow.h
#ifndef ROUNDEDWINDOW_H
#define ROUNDEDWINDOW_H#include <QtCore/qglobal.h>
#if QT_VERSION >= 0x050000
#include <QtWidgets/QWidget>
#else
#include <QtGui/QWidget>
#endifclass RoundedWindow : public QWidget {Q_OBJECT
public:explicit RoundedWindow(QWidget *parent = nullptr);void init();protected:void paintEvent(QPaintEvent *event) override;signals:
};#endif // ROUNDEDWINDOW_Hroundedwindow.cpp
#include "roundedwindow.h"
#include <QPainter>
#include <QPushButton>
#include <QVBoxLayout>RoundedWindow::RoundedWindow(QWidget *parent) : QWidget{parent} {/* setAttribute 与 setWindowFlag 尽量写在构造函数，写在其他操作之前 */// 背景透明this->setAttribute(Qt::WA_TranslucentBackground, true);// 无边框this->setWindowFlag(Qt::FramelessWindowHint);
}void RoundedWindow::init() {this->show();QLayout *mainLayout = new QVBoxLayout{this};QPushButton *btn = new QPushButton{this};btn->setText(QStringLiteral("你好"));mainLayout->addWidget(btn);this->setLayout(mainLayout);
}void RoundedWindow::paintEvent(QPaintEvent *event) {QPainter painter{this};painter.setRenderHint(QPainter::Antialiasing); // 抗据齿,绘图更加平滑painter.setBrush(QBrush{QColor{155, 54, 54}});painter.drawRoundedRect(this->rect(), 15, 15);
}利用qss改变主窗口样式
main.cpp
#include <QtCore/qglobal.h>
#if QT_VERSION >= 0x050000
#include <QtWidgets/QApplication>
#else
#include <QtGui/QApplication>
#endif#include "roundedwindow.h"int main(int argc, char *argv[]) {QApplication a(argc, argv);RoundedWindow wnd{};wnd.init();return a.exec();
}roundedwindow.h
#ifndef ROUNDEDWINDOW_H
#define ROUNDEDWINDOW_H#include <QtCore/qglobal.h>
#if QT_VERSION >= 0x050000
#include <QtWidgets/QWidget>
#else
#include <QtGui/QWidget>
#endifclass RoundedWindow : public QWidget {Q_OBJECT
public:explicit RoundedWindow(QWidget *parent = nullptr);void init();protected:void paintEvent(QPaintEvent *event) override;signals:
};#endif // ROUNDEDWINDOW_Hroundedwindow.cpp
#include "roundedwindow.h"
#include <QPainter>
#include <QPushButton>
#include <QStyleOption>
#include <QVBoxLayout>RoundedWindow::RoundedWindow(QWidget *parent) : QWidget{parent} {/* setAttribute 与 setWindowFlag 尽量写在构造函数，写在其他操作之前 */// 背景透明this->setAttribute(Qt::WA_TranslucentBackground, true);// 无边框this->setWindowFlag(Qt::FramelessWindowHint);
}void RoundedWindow::init() {this->show();this->setStyleSheet("QWidget {"" background-color:gray;"" border-radius:15px;""}");
}void RoundedWindow::paintEvent(QPaintEvent *event) {Q_UNUSED(event);/* qwidget的qss仅支持background、background-clip和background-origin属性。* 如果您继承QWidget，则需要为自定义QWidget提供paintEvent，如下所示 */QStyleOption opt;opt.initFrom(this);QPainter p(this);style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);
}
)
)
)
