Qt5.12.1未知类型名称QChart / QWidget / QEvent /

Question

I've installed Qt5.12.1 and trying to open a working project but its giving me errors. I dont have experience with Qt neither C++ but I need to fix some bugs in this project. It gives lots of errors like this and I'm using Qt Creator because I dont have access to internet from my work computer.

Code where it gives error goes like this:

#include "chartview.h"
#include <QMouseEvent>
#include <qdebug.h>
#include <QtCharts/qxyseries.h>
#include "configvalues.h"
#include "qmath.h"

ChartView::ChartView(QChart *chart , QWidget *parent):
    QChartView(chart,parent), m_isTouching(false), delta(20) {
int rubberBand = ConfigValues::instance()->settings->value(Chart/"RubberBand").toInt();
    QColor c1 = ConfigValues::instance()->settings->value("Chart/TooltipColor").value<QColor>();
    setRubberBand((QChartView::RubberBands) rubberBand);

In this code, QChart and QWidget gives error and because of them so does ChartView. Why I'm having these errors?

Edit:

In ChartView.h file 

#ifndef CHARTVIEW_H
#define CHARTVIEW_H

#include <QchartView>
#include <qrubberband.h>
#include <QDateTime>

exist. But only QDateTime is not giving any error. Others giving "file not found"

Answer 1

hmmmm hi it'd be much more easier if you would offer an error log also. but as much as I know these errors are due to the compiler that cannot find the packages mentioned when compiling. if you have the errors like unknown type : QWidget, QChart, QEvent it probably will be fixed if you import the packages of QtCore and QtCharts to the project and that will be done like this: go to project qmake file like : project.pro add these lines to it:

QT += core widgets charts