1.运行界面

2.源码 

//.h
#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

namespace Ui {
class Widget;
}


class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

private:
    Ui::Widget *ui;

};

#endif // WIDGET_H


//.cpp
#include "widget.h"
#include "ui_widget.h"
#include <QGraphicsDropShadowEffect>
#include <QColor>

const int g_maxValue = 50;

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setStyleSheet("background-color: rgb(255, 255, 255);");
    ui->frame->setStyleSheet("background-color: rgb(0, 0, 0);");
    ui->frame->setStyleSheet("border-radius:8px;");

    //设置具体阴影
    QGraphicsDropShadowEffect *shadow_effect = new QGraphicsDropShadowEffect(this);
    shadow_effect->setOffset(0, 0);

    //阴影颜色
    shadow_effect->setColor(QColor(38, 78, 119, 127));

    //阴影半径
    shadow_effect->setBlurRadius(22);

    ui->frame->setGraphicsEffect(shadow_effect);
}

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