Qt为所有对话框设置通用背景

#include <QtWidgets>

class CustomDialog : public QDialog
{
public:
    CustomDialog(QWidget *parent = nullptr)
        : QDialog(parent)
    {
        // 设置对话框的背景颜色
        QPalette palette;
        palette.setColor(QPalette::Background, Qt::lightGray);
        setPalette(palette);
    }

protected:
    void paintEvent(QPaintEvent *event) override
    {
        // 绘制背景图片
        QPainter painter(this);
        painter.drawPixmap(rect(), QPixmap(":/images/background.png"));
    }
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    // 创建自定义对话框对象
    CustomDialog dialog;
    dialog.setWindowTitle("Custom Dialog");
    dialog.resize(400, 300);

    // 显示对话框
    dialog.show();

    return app.exec();
}