首先ui设计中分别创建了4个大灯和4个小灯。

编辑.h文件

#ifndef LED_H
#define LED_H

#include <QWidget>
#include <QLabel>

QT_BEGIN_NAMESPACE
namespace Ui { class Led; }
QT_END_NAMESPACE

class Led : public QWidget
{
    Q_OBJECT

public:
    Led(QWidget *parent = nullptr);
    ~Led();

private:
    void initData();
    void initUi();

private:
    Ui::Led *ui;
    QVector<QString> color_s;   ///< 存放设置小灯的样式字符串
    QVector<QString> color_b;   ///< 存放设置大灯的样式字符串
    enum colorType {GREY = 0, RED, GREEN, YELLOW};  ///< 灯颜色枚举
};
#endif // LED_H

编辑.cpp文件

#include "led.h"
#include "ui_led.h"

Led::Led(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Led)
{
    ui->setupUi(this);
    initData();
    initUi();
}

Led::~Led()
{
    delete ui;
}

void Led::initData()
{
    QString comm_s("min-width:20px;min-height:20px;max-width:20px;max-height:20px;border-radius:13px;border:3px rgb(147, 147, 147);border-style:outset;");
    color_s.push_back(comm_s + QString("background-color:rgb(195, 195, 195);"));    ///< GREY
    color_s.push_back(comm_s + QString("background-color:rgb(255, 0, 0);"));        ///< RED
    color_s.push_back(comm_s + QString("background-color:rgb(0, 255, 0);"));        ///< GREEN
    color_s.push_back(comm_s + QString("background-color:rgb(255, 255, 0);"));      ///< YELLOW

    QString comm_b("min-width:34px;min-height:34px;max-width:34px;max-height:34px;border-radius:20px;border:3px rgb(147, 147, 147);border-style:outset;");
    color_b.push_back(comm_b + QString("background-color:rgb(195, 195, 195);"));    ///< GREY
    color_b.push_back(comm_b + QString("background-color:rgb(255, 0, 0);"));        ///< RED
    color_b.push_back(comm_b + QString("background-color:rgb(0, 255, 0);"));        ///< GREEN
    color_b.push_back(comm_b + QString("background-color:rgb(255, 255, 0);"));      ///< YELLOW
}

void Led::initUi()
{
    ui->leds1->setStyleSheet(color_s[GREY]);
    ui->ledb1->setStyleSheet(color_b[GREY]);

    ui->leds2->setStyleSheet(color_s[RED]);
    ui->ledb2->setStyleSheet(color_b[RED]);

    ui->leds3->setStyleSheet(color_s[GREEN]);
    ui->ledb3->setStyleSheet(color_b[GREEN]);

    ui->leds4->setStyleSheet(color_s[YELLOW]);
    ui->ledb4->setStyleSheet(color_b[YELLOW]);
}

效果这样：