Automatically crashed my application at the time of using series->append() function in timer slot

Sekhar

I developed a simple QChart application for dynamically update values in every second using Qtimer concept. and this is my code...
mainwindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include<QtCharts>

using namespace QtCharts;

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

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

public slots:
    void handleTimeout();

private:
    QChart *chart;
    QChartView *chartView;
    QTimer *m_timer;
    //QSplineSeries *m_series;
    QLineSeries *m_series;
    QStringList m_titles;
    QValueAxis *m_axis;
    qreal m_step;
    qreal m_x;
    qreal m_y;

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

main.cpp:


#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow window;
    window.show();

    return a.exec();
}

mainwindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include<QChart>
#include<QChartView>
#include<QLineSeries>
#include<QAbstractSeries>
#include<QGridLayout>
#include<QTimer>

#include<QtCharts/QChartView>
#include<QtCharts>
#include<QDebug>

using namespace QtCharts;

qreal x1=0;
qreal z1=0;
int i=0;

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

       m_series = new QLineSeries();

       // create Chart Object (QWidget)
       chart = new QChart();
       chart->legend()->hide();
       chart->addSeries(m_series );
       chart->createDefaultAxes();
       chart->setTitle("Histogramm");


     QValueAxis *xAxis = new QValueAxis;
     QValueAxis *yAxis = new QValueAxis;
     chart->setAxisX(xAxis, m_series );
     chart->setAxisY(yAxis, m_series );
     xAxis->setMax(5);
     yAxis->setMax(5);

     m_timer = new QTimer();

     connect(m_timer,SIGNAL(timeout()),this,SLOT(handleTimeout()));
     m_timer->setInterval(1000);

       // create a view inside the Chart
     QChartView *chartView = new QChartView(chart, this);
     ui->verticalLayout->addWidget(chartView);

    chart->setAnimationOptions(QChart::AllAnimations);

       m_timer->start();

}

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

void MainWindow::handleTimeout()
{
    if(i>10)
      {
        m_timer->stop();
      }
    else {
           x1 += 1;
           z1 += 0.5;
             i += 1;
           m_series->append(x1,z1);
           ui->label->setText(QString::number(i));
         }

   QChartView *chartView = new QChartView(chart, this);
   ui->verticalLayout->addWidget(chartView);
}

if the code doesn't works, when i was using "m_series->append()" function in timer slot and application automatically crashed.

Christian Ehrlicher

I don't see a place where you initialize m_series.

Sekhar

@Christian-Ehrlicher
sorry i was forgot my actual code now i was updated.

J.Hilk

@Sekhar
@Christian-Ehrlicher point still stands, where do you initialize m_series? in your constructor your initialize series, clearly a different variable

Sekhar

problem solved. Thanks for your guidance.

Christian Ehrlicher

@Sekhar Then please mark the topic as solved, thx