ubuntu 中的 C++ Qt 尝试新的 ZA8CFDE6331BD59EB2AC96F8911C4B6Z6 时出现分段错误

Question

I'm trying to use Qchart in ubuntu. I have a segmentation fault(sigsegv) error when running the code below. This error exists when creating the Qchart object.

header file:

#include <QtCharts/QChart>
#include <QtCharts/QChartView>
#include <QtCharts/QLineSeries>
using namespace QtCharts;
class Test
{
  public:
    Test();
    ~Test();
    void Run();
  private:
    QLineSeries *series;
    QChart *chart;
    QChartView *chartView;
};

cpp file:

#include "test.h"
Test::Test()
{        
  series = new QLineSeries();
  chart = new QChart();
  chartView = new QChartView(chart);
}

void Test::Run(){
  series->append(0, 6);
  series->append(2, 4);
  series->append(3, 8);
  series->append(7, 4);
  series->append(10, 5);
  chart->legend();
  chart->addSeries(series);
  chart->createDefaultAxes();
  chart->setTitle("Simple line chart example");
  chartView->setRenderHint(QPainter::Antialiasing);
  chartView->show();
}
Test::~Test(){
  delete series;
  delete chart;
  delete chartView;
}

What's the problem? And how to fix this error?

Answer 1

I don't know if you still need help about this but in case someone does, I will share my solution.

First of all, you need to ensure QApplication is declared and working correctly (do not confuse with QGuiApplication ).

Secondly, if you necessarily need to modularize the chart (like you do by defining the Test class and define the chart attributes in it), you need to initialize the QChart (or the function or constructor that includes the initialization of QChart ) in main window widget's constructor. In Windows, this approach would solve your problem:

in mainwindow.h:

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
   Test testObject;
   //other stuff
}

in mainwindow.cpp

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) , ui(new Ui::MainWindow)
{

    testObject = Test();
    //other stuff
}

Note that MainWindow is default QMainWindow widget class in Windows.

I am not sure but the source of the problem might be Q_DISABLE_COPY(QChart) line in qchart.h file. It needs to throw a compile-time error but instead causes a segmentation fault on runtime.