在另一个 class 中使用 QNetworkRequest

Question

I have a get_curl () method in the mainWindow class. I want to move this method into a separate class so that it can be used from any part of the program. i tried to do this but nothing worked. I understand that the problem is in the connect () that I used in my Utils class. I need that I can call a method the same method get_curl () but from my Utils class

And i delete some of my code

MainWindow.h

#pragma once

#include <QtWidgets/QMainWindow>
#include "ui_MainWindow.h"

#include <qstackedwidget.h>
#include <qstatusbar.h>

#include <qstring.h>

#include <qdebug.h>
#include <qtextcodec.h>
#include <qvariant.h>

#include <QtNetwork/qnetworkaccessmanager.h>
#include <QtNetwork/qnetworkrequest.h>
#include <QtNetwork/qnetworkreply.h>



class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = Q_NULLPTR);

private:
    Ui::MainWindowClass ui;

    QNetworkAccessManager* manager;
    QNetworkRequest request;
    QNetworkReply* reply;

    QString contents;
    QString err;

    void get_curl();
    void set_btn_clicks();

private slots:
    void on_btn();

    void on_btnRmouteClicked();



    void slott(QNetworkReply*);
};

MainWindow.cpp

#include "MainWindow.h"

#include "Utils.h"

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
{
    ui.setupUi(this);
    
    set_btn_clicks();   
}

void MainWindow::set_btn_clicks()
{      
    connect(ui.btnRemoute, SIGNAL(clicked()), this, SLOT(on_btnRmouteClicked()));
    
}//MENU BTN CLICKS

#pragma region Engine
void MainWindow::get_curl()
{
    manager = new QNetworkAccessManager();
    request.setUrl(QUrl("https://auth.pentagon.com/api/client/account"));
    request.setRawHeader("Accept", "application/json");
    request.setHeader(QNetworkRequest::ContentTypeHeader, QVariant("application/json"));
    request.setRawHeader("Authorization", "Bearer xxx");


    reply = manager->get(request);
    connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(slott(QNetworkReply*)));
}
void MainWindow::slott(QNetworkReply*)
{
    if (reply->error() == QNetworkReply::NoError)
    {
        contents = QString::fromUtf8(reply->readAll());
        qDebug() << contents;
    }
    else
    {
        err = reply->errorString();
        qDebug() << err;
    }
}
#pragma endregion

#pragma region BtnClicks
void MainWindow::on_btn()
{
    get_curl();
}

void MainWindow::on_btnRmouteClicked()
{
    get_curl();
    Utils u;
    u.print_curl();
    ui.stackedWidget->setCurrentWidget(ui.pageRemoute);
}

#pragma endregion

Answer 1

Connect the finished signal to a C++ lambda that is passed in from outside. This is only possible using the new connection syntax:

using url_cb = std::function<void(QNetworkReply*)>;
void url_get(QNetworkRequest request, url_cb cb) {
    auto manager = new QNetworkAccessManager;
    QObject::connect(manager, &QNetworkAccessManager::finished, manager, &QObject::deleteLater);
    QObject::connect(manager, &QNetworkAccessManager::finished, manager, cb);
    manager->get(request);
}

You can then rewrite MainWindow::on_btnRmouteClicked() as follows:

void MainWindow::on_btnRmouteClicked() {
    QNetworkAccessRequest request;
    request.setUrl(QUrl("https://auth.pentagon.com/api/client/account"));
    request.setRawHeader("Accept", "application/json");
    request.setHeader(QNetworkRequest::ContentTypeHeader, QVariant("application/json"));
    request.setRawHeader("Authorization", "Bearer xxx");
    url_get(request, [=](QNetworkReply * rep) {
        if (reply->error() == QNetworkReply::NoError) {
            contents = QString::fromUtf8(reply->readAll());
            qDebug() << contents;
        } else {
            err = reply->errorString();
            qDebug() << err;
        }

        Utils u;
        u.print_curl();
        ui.stackedWidget->setCurrentWidget(ui.pageRemoute);
    });
}