The Qt charting module is unresponsive

[baizhou]

qt charts module, adding data through QLineSeries is not reflected, and I have added QLineSeries to the chart, adding static data is also possible, but the dynamic will not respond.
This is my chart data insertion function

void hum_wdiget::syn_hum_charts()
{
    qDebug() << "syn_hum_charts called with hum = " << hum;
      second++;
    int humidity = hum;
      qDebug() << "humidity =" << humidity;
    series_hum->append(second, humidity);
    chart_hum->update();
    view_hum->repaint();     //Manually trigger a chart redraw
    axis_hum->setRange(second - 10, second + 10); // Let's say we want to display data from the last 10 seconds 

    // Force processing of unprocessed events to help ensure that the view is updated in a timely manner
    QCoreApplication::processEvents();
    update();
}

Here are the test results of my running function, which means that the function is working properly
syn_hum_charts called with hum = 52
humidity = 52
But nothing has changed in the chart
So I tested it and inserted it statically at creation time

   series_hum->append(1, 20);
   series_hum->append(2, 30);
   series_hum->append(3, 40);
   series_hum->append(5, 20);
   series_hum->append(6, 20);

The insertion was found to be successful
After that, I tested the function directly with a timer, and the Debug test data result and the above result have been the same, but the inserted data is always the x-axis is second, and the y-axis humidity = hum is the defined value of hum

connect(timer, &QTimer::timeout, this, &hum_wdiget::syn_hum_charts);

[JonB]

@baizhou
Please do not duplicate posts --- https://forum.qt.io/topic/155204/qt-charts-module-bug-issues/3. It is not polite to those who would respond and find the same topic being discussed in multiple places.

[baizhou]

@JonB Hi, thank you very much for your reply and reminder, I apologize for my previous ignorance behavior, but the reason is because I found that my issue was miscategorized, so I want to delete the previous post and resend it. I listened to you and have already made a minimal case.
Header file
charts_data.h

#ifndef CHARTS_DAT[link text]A_H
#define CHARTS_DATA_H

#include <QWidget>
#include <QtCharts>
#include <QDebug>
using namespace QtCharts;

namespace Ui {
class charts_data;
}

class charts_data : public QWidget
{
    Q_OBJECT

public:
    explicit charts_data(QWidget *parent = nullptr);
    ~charts_data();

    //initialize
    void charts_init();

    //Set up the receive function
    void receive_function(int d_received);

    //Chart updates
    void charts_update_function();

    void create_charts();

private:
    int second;

    //Data received
    int data_received;

    //chart subassembly
    QChart* chart_data;
    QLineSeries* series_data;
    QChartView* view_data;
    QValueAxis* axis_data_x;
    QValueAxis* axis_data_y;
    QVBoxLayout* vbox_data;

private:
    Ui::charts_data *ui;

};

#endif // CHARTS_DATA_H

data.h

#ifndef DATA_H
#define DATA_H

#include <QWidget>
#include <charts_data.h>
#include <QTime>

QT_BEGIN_NAMESPACE
namespace Ui { class data; }
QT_END_NAMESPACE

class data : public QWidget
{
    Q_OBJECT

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

    //initialize
    void data_init();


private:
    charts_data* c_data;

    int test_data;

    QTimer* timer;

private slots:
    //Transfer the data to the chart file
    void Transfer_data();

private:
    Ui::data *ui;
};
#endif // DATA_H

Source files
charts_data.cpp

#include "charts_data.h"
#include "ui_charts_data.h"

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

    charts_init();

    create_charts();
}

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

void charts_data::charts_init()
{
    second = 0;
    chart_data = new QChart;
     series_data = new QLineSeries;
     view_data = new QChartView;
     axis_data_x = new QValueAxis;
     axis_data_y = new QValueAxis;
     vbox_data = new QVBoxLayout;
}

void charts_data::receive_function(int d_received)
{
     data_received = d_received;
     charts_update_function();
}

void charts_data::charts_update_function()
{
     qDebug() << data_received;
     second++;
    series_data->append(second,data_received);
}

void charts_data::create_charts()
{
    //Set the polyline
    series_data->setName("湿度");
    series_data->setPointLabelsVisible(true);
    series_data->setPointsVisible(true);
    series_data->setPointLabelsFormat("@yPoint");

        series_data->append(1, 20);
        series_data->append(2, 30);
        series_data->append(3, 40);
        series_data->append(5, 20);
        series_data->append(6, 20);

    //Set the axes
    axis_data_x->setRange(0, 10);
    axis_data_x->setTitleText("time（s）");
    axis_data_y->setRange(0, 100);
    axis_data_y->setTitleText("data（%）");

    //Create a table
    chart_data= new QChart();
    chart_data->setTitle("Humidity polyline");
    chart_data->addAxis(axis_data_x,Qt::AlignBottom);
    chart_data->addAxis(axis_data_y, Qt::AlignLeft);
    chart_data->setMargins(QMargins(10, 10, 10, 10));
    chart_data->createDefaultAxes();
    chart_data->legend()->setVisible(true);
    chart_data->addSeries(series_data);

    //The sequence is added to the axes
    series_data->attachAxis(axis_data_x);
    series_data->attachAxis(axis_data_y);

    //Set the view
    view_data->setChart(chart_data);
    view_data->setRenderHint(QPainter::Antialiasing);

    // Add a view to the layout)
    vbox_data->addWidget(view_data);
    setLayout(vbox_data);

    // Resize the view to fit its contents
    view_data->fitInView(chart_data->plotArea(), Qt::KeepAspectRatio);
}

data.cpp

#include "data.h"
#include "ui_data.h"

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

    data_init();

    //The timer transmits data every second, which triggers the chart file to update the chart
    connect(timer, &QTimer::timeout, this, &data::Transfer_data);
    timer->start(1000);
}

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

void data::data_init()
{
    test_data = 0;
    c_data = new charts_data();
    timer = new QTimer;
}

void data::Transfer_data()
{
    test_data++;
    c_data->receive_function(test_data);
}

main.cpp

#include "data.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    data w;
    w.show();
    return a.exec();
}

Interface files
charts_data.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>charts_data</class>
 <widget class="QWidget" name="charts_data">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>400</width>
    <height>300</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Form</string>
  </property>
 </widget>
 <resources/>
 <connections/>
</ui>

data.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>data</class>
 <widget class="QWidget" name="data">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>800</width>
    <height>600</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>data</string>
  </property>
  <widget class="charts_data" name="widget" native="true">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>801</width>
     <height>601</height>
    </rect>
   </property>
  </widget>
 </widget>
 <customwidgets>
  <customwidget>
   <class>charts_data</class>
   <extends>QWidget</extends>
   <header>charts_data.h</header>
   <container>1</container>
  </customwidget>
 </customwidgets>
 <resources/>
 <connections/>
</ui>

example.pro

QT       += core gui charts

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++17

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
    charts_data.cpp \
    main.cpp \
    data.cpp

HEADERS += \
    charts_data.h \
    data.h

FORMS += \
    charts_data.ui \
    data.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

[JonB]

@baizhou
This is awfully far from being a minimal example.... Can't you just get rid of 90% of your convoluted code and try adding a few new points to a line series on a timer?

I note that you create two new QCharts, one in charts_init() another in create_charts(). I'm not going to figure the consequence of that.

I also believe you create a "static" point (as you call it) like series_data->append(1, 20);, and then if you work through your code I think you create a new "dynamic" point (as you call it) also at series_data->append(1, ...) because second counts again from 0? In which case, you now have multiple points at x==1 so how do you know the new, second point has not been created?

If I were you I would simplify your code to a minimal example and check behaviour.

[baizhou]

@JonB Hello, according to your suggestion, I have located the problem I am in from a small program just now and has changed it successfully, thank you very much for your suggestion to me, and also let me learn a new way to solve the problem. However, I am vague about the specifications of a minimal case, and I have minimized my question as much as possible, and I may also ask my questions in the future, and I will go to other questions to learn.

[JonB]

@baizhou said in The Qt charting module is unresponsive:

Hello, according to your suggestion, I have located the problem I am in from a small program just now and has changed it successfully

And what did you change/why is it successful now? It helps if you tell us :) Was it that the new points were being added, but because you were re-using the same x-coordinate as an existing point you just did not see it?

[baizhou]

@JonB I minimized the issue and rediscovered that the reason why I wasn't showing updates to the data was because my charts belonged to different objects

hum_wdiget * H_wdiget;

I define an object pointer so that the data passed through the object pointer belongs only to that object.
So, I commented out the code that created the view in the diagram file and added it to the layout
hum_wdiget.cpp

void hum_wdiget::create_hum_charts()
{
...other code...
//    vbox_hum->addWidget(view_hum);
//    setLayout(vbox_hum);
}

After that, I created the chart in the main interface directly from the object, and added the following paragraph.
widget.cpp

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

    vbox_hum = new QVBoxLayout();
    vbox_hum->addWidget(H_wdiget->view_hum);
    setLayout(vbox_hum);
}