QT       += core gui charts

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>


#include <QLabel>

#include <QtCharts>

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

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

    void resizeEvent(QResizeEvent *event);

      QLabel *m_centerLabel;

      QChartView *b;

private:
    Ui::Widget *ui;
};
#endif // WIDGET_H

widget.cpp

#include "widget.h"




QT_CHARTS_USE_NAMESPACE


#include "ui_widget.h"


#include <QtWidgets>
 #include <QtCharts>


Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);


    QGridLayout *a=new QGridLayout;


    ui->ycn->setLayout(a);

    b=new QChartView;

    a->addWidget(b);


    QPieSeries* series = new QPieSeries();                              // 创建一个圆环图对象
    series->setHoleSize(0.45);                                          // 设置圆环孔径大小0.0 ~1.0
    series->append("蛋白质占比 9.2%", 9.2);                              // 将具有指定值和标签的单个切片附加到series
    series->append("其它 23.8%", 23.8);
    series->append("碳水化合物 51.4%", 51.4);
    QPieSlice* slice = series->append("脂肪占比 15.6%", 15.6);           // 设置一个圆环切片，并返回这个切片对象
    slice->setExploded();                                               // 将当前切片分离
    slice->setLabelVisible();                                           // 显示当前切片的标签，默认是不显示的

   b->setRenderHint(QPainter::Antialiasing);               // 设置抗锯齿
    b->chart()->setTitle("圆环图标题");                       // 设置图表标题
   b->chart()->addSeries(series);                          // 将创建的圆环对象添加进chart中
    b->chart()->setTheme(QChart::ChartThemeBlueCerulean);   // 设置图表的样式
   b->chart()->legend()->setAlignment(Qt::AlignBottom);    // 指定图例显示在图表底部
   b->chart()->legend()->setFont(QFont("Arial", 12));       // 设置图例的字体


   m_centerLabel = new QLabel("80%", b);
   m_centerLabel->setStyleSheet(QString("background:transparent;font-family:\"Mircsoft Yahei\";"
                                        "font-size:20px; color:#1564FF; font-weight:bold;"));
  // m_centerLabel->hide();


}


void Widget::resizeEvent(QResizeEvent *event)
{

    m_centerLabel->move(b->width()/2+m_centerLabel->width()/2,
                        b->height()/2);


}


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