I'm trying to use the simple linechart example to work in my code. I'm trying to get the chart window to display from within a button function that does some calculations to get the data points. When the time comes for the chart to display, I can see it pop up and disappear almost instantly. After a lot of reading, I think it has to do with trying to create a new QMainWindow from inside the button? Here is my most recent code that is supposed to set up the chart window:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "QtCharts/QChartView"
#include "QtCharts/QLineSeries"
#include "QtCharts/QLegend"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    //  Hide all Buttons            //
    ui->btnHeading->setVisible(false);
}
    QMainWindow *chartWindow = new QMainWindow(0);
    chartWindow->setCentralWidget(&ChartView);
    chartWindow->resize(800,600);

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

And here is the button that is supposed to display the chart:

void MainWindow::on_btnHeading_clicked()
{
    QLineSeries *series = new QLineSeries();

    PGNListCount = PGNList.count();
    qDebug() << PGNListCount;
    for (int i=0;i<PGNListCount;i++) {
        if (PGNList.at(i).contains("127250")) {
            DB21Data << DB2.at(i) + (DB1.at(i));
            //graphTime << timeStamp.at(i);
            }
     }

    int DB21DataCount = DB21Data.count();
    for (int i=0; i<DB21DataCount;++i) {
        DB21hex = (((DB21Data.at(i).toInt(&ok, 16))*0.0001)*57.296);
        series->append(i, DB21hex);
        //qDebug() << series << DB21hex;
    }

    QChart *chart = new QChart();
        chart->legend()->hide();
        chart->addSeries(series);
        chart->createDefaultAxes();
        chart->setTitle("Heading");

    QChartView *chartView = new QChartView(chart);
        chartView->setRenderHint(QPainter::Antialiasing);

//        QMainWindow window;
//            window.setCentralWidget(chartView);
//            window.resize(800, 600);
            chartWindow->show();

}

I've tried a few different things - this code errors on the two lines:

chartWindow->setCentralWidget(&ChartView);
    chartWindow->resize(800,600);

with "chartWindow does not name a type"

Any hints on how I can approach this would be much appreciated!