Why am I using ui->graphicsView->setChart(chart); The program is compiled, but when it is running, it directly "ends abnormally"

Lee_Corl

This is my ui

When I choose to comment out this sentence, the program shows an exception, but it runs without an error
But when I didn't comment out this sentence, the program didn't work properly

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QTimer>       // 定时器
#include <QTime>        // 用于设置随机数种子
#include <qdebug.h>     // 用于调试输出
#include <QMessageBox>

float PID_Work(float Error, float kp, float ki, float kd);
#define Ts (1000)

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    QTimer *tim = new QTimer(this);

    QChart *chart = new QChart();
    chart->setTitle("PID算法");

    chart->legend()->setVisible(true);

    /* 坐标轴 */
    QValueAxis *AxisX = new QValueAxis(this);
    QValueAxis *AxisY = new QValueAxis(this);

    //    chart->setAxisX(AxisX);
    //    chart->setAxisY(AxisY);

    chart->addAxis(AxisX, Qt::AlignBottom);
    chart->addAxis(AxisY, Qt::AlignLeft);

    AxisX->setRange(0, 100);
    AxisY->setRange(0, 100);
    AxisX->setTitleText("时间/ms");
    AxisY->setTitleText("温度/°C");

//    /* 曲线 */
    QSplineSeries *series = new QSplineSeries(this);

    chart->addSeries(series);

    series->attachAxis(AxisX);
    series->attachAxis(AxisY);
    series->setPointLabelsClipping(false);
    series->setName("PID曲线");

    QPen pen;
    pen.setColor(QColor(0, 0, 255));
    series->setPen(pen);

    if (!ui->graphicsView) {
        qDebug() << "graphicsView is not initialized!";
        return;
    }

    ui->graphicsView->setChart(chart);

    connect(this, &MainWindow::StartChart, this,  [=](){
        tim->start(Period);
    });

    connect(tim, &QTimer::timeout, this, [=](){
        static int i = 0;
        float ret = PID_Work((GoalNum - CurrentNum), KP, KI, KD);
        series->append(i * Period, ret);
        CurrentNum += ret;
        qDebug()<<"OUTPUT = "<< PID_output;
        qDebug()<<"CurrentTemp = "<< CurrentNum;
    });
}

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

float PID_Work(float Error, float kp, float ki, float kd)
{
    static float lastError = 0.0f;
    static float Errorsum  = 0.0f;

    // 设置随机数种子
    qsrand(QTime::currentTime().msec());

    /* 生成 0 到 30 之间的随机浮点数  用于假设环境中存在的干扰*/
    float randomFloat = (qrand() / static_cast<float>(RAND_MAX)) * 30;

    qDebug() << "生成的随机浮点数是:" << randomFloat;

    Errorsum += Error;
    float derivative = (Error - lastError) / Ts;  // 计算微分项
    lastError = Error;  // 更新 lastError 在计算完微分项之后

    return kp * Error + ki * Errorsum + kd * derivative - randomFloat;
}


void MainWindow::on_pushButton_clicked()
{
    static bool ok = true;
    static bool tmp;
    QString str = ui->GoalTemp->text();
    GoalNum = str.toFloat(&tmp);
    ok = ok & tmp;

    str = ui->InitTemp->text();
    CurrentNum = str.toFloat(&tmp);
    ok = ok & tmp;

    str = ui->Period->text();
    Period = str.toInt(&tmp);
    ok = ok & tmp;

    str = ui->KP->text();
    KP = str.toFloat(&tmp);
    ok = ok & tmp;

    str = ui->KI->text();
    KI = str.toFloat(&tmp);
    ok = ok & tmp;

    str = ui->KD->text();
    KD = str.toFloat(&tmp);
    ok = ok & tmp;

    if(!ok)
    {
        QMessageBox::warning(this, "错误警告", "输入错误");
    }else {
        emit StartChart();
    }
}

SGaist

Hi and welcome to devnet,

You deleted the setupUi call which means that your widget is not properly initialized before you start using its components.

Lee_Corl

@SGaist ohhh,Thank you very much.It's OK!

SGaist

Great !
Then please mark the thread as solved using the Topic Tools button or the three dotted menu beside the answer you deem correct so other forum users may know a solution has been found :-)