缺少QObject派生类

missing derived class with QObject

本文关键字：派生 QObject 缺少      更新时间：2023-10-16

我得到错误~ MainWindow .cpp:9:错误:'MainWindow::MainWindow(QWidget*)' MainWindow::MainWindow(QWidget* parent)的重新定义:我很确定它是在抱怨错误的派生类名称。基类是MainWindow，但是我不知道派生类是什么。

//mainwindow.cpp 

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QNetworkAccessManager>
#include <QUrl>
#include <QNetworkRequest>
#include <QNetworkReply>
#include <QImageReader>
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
MainWindow::~MainWindow()
{
    delete ui;
}
void coreEng::requestPage(){
    QUrl url("http://www.nyctelecomm.com");
    QNetworkReply* reply = nam->get(QNetworkRequest(url));
}
void coreEng::finishedSlot(QNetworkReply* reply){
    QVariant statusCodeV = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
    QVariant redirectionTargetUrl = reply->attribute(QNetworkRequest::RedirectionTargetAttribute);
    if (reply->error() == QNetworkReply::NoError)
    {
        QImageReader imageReader(reply);
        QImage pic = imageReader.read();
        QByteArray bytes = reply->readAll();  // bytes
        QString string(bytes); // string
    }
    else
    {
    }
//    delete reply();
}
void MainWindow::on_lcdNumber_overflow()
{
    QByteArray replyData = netReply->readAll();
}
void MainWindow::on_pushButton_clicked()
{
    QObject::on_pushButton_clicked(nam, SIGNAL(finished(QNetworkReply*)),
    this, SLOT(finishedSlot(QNetworkReply*)));
}
//mainwindow.h 

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QObject>
#include <QNetworkAccessManager>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    explicit MainWindow(QWidget *parent = 0):
    QMainWindow(parent)
        {
            nam = new QNetworkAccessManager();
        }
    ~MainWindow();
private:
    Ui::MainWindow *ui;
public slots:
    //void connect();
    void on_pushButton_clicked();
    void requestPage();
    void finishedSlot(QNetworkReply* reply);
private slots:
    void on_lcdNumber_overflow();
private:
    QNetworkAccessManager* nam;
};
#endif // MAINWINDOW_H
//main.cpp 

#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow mConnect;
    mConnect.on_pushButton_clicked();
    mConnect.requestPage();
    MainWindow w;
    w.show();
    return a.exec();
}

您已经定义了两次MainWindow::MainWindow。首先是头文件，其次是源文件。

explicit MainWindow(QWidget *parent = 0):
QMainWindow(parent)
    {
        nam = new QNetworkAccessManager();
    }

//

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