Adding code example to QT C++ - c++

Question

I'd like to add some QT example code to my simple project. The sample code is here: https://wiki.qt.io/Download_Data_from_URL
It consists of filedownloader.cpp and filedownloader.h -- this code downloads a graphic from a supplied URL.
I've added these files to my project and get a clean compile. I think I understand the code ok (I'm mainly a c coder, not c++) but I don't understand how I can pass the QUrl created by my project to filedownloader.cpp
The "project" is just a simple main.cpp/mainwindow.cpp/mainwindow.ui that offers a button to be pressed. Pressing the button calls the routine below:
void MainWindow::on_pushButton_clicked()
{
// pass to filedownloader to process
QUrl fileloc("http://www.test.com/test.jpg");
}
How do I feed the QUrl fileloc to filedownload.cpp?

Answer 1

You have to add a new method to FileDownloader, that accepts QUrl and starts the download.
filedownloader.h:
#ifndef FILEDOWNLOADER_H
#define FILEDOWNLOADER_H
#include <QObject>
#include <QByteArray>
#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkReply>
class FileDownloader : public QObject
{
Q_OBJECT
public:
explicit FileDownloader(QUrl imageUrl, QObject *parent = 0);
virtual ~FileDownloader();
QByteArray downloadedData() const;
signals:
void downloaded();
public slots:
void download(QUrl url); // <------ Here it is
private slots:
void fileDownloaded(QNetworkReply* pReply);
private:
QNetworkAccessManager m_WebCtrl;
QByteArray m_DownloadedData;
};
#endif // FILEDOWNLOADER_H
filedownloader.cpp:
#include "filedownloader.h"
FileDownloader::FileDownloader(QObject *parent) :
QObject(parent)
{
connect(
&m_WebCtrl, SIGNAL (finished(QNetworkReply*)),
this, SLOT (fileDownloaded(QNetworkReply*))
);
// <------ Notice, that i've removed downloading code from here
}
FileDownloader::~FileDownloader() { }
void FileDownloader::fileDownloaded(QNetworkReply* pReply) {
m_DownloadedData = pReply->readAll();
//emit a signal
pReply->deleteLater();
emit downloaded();
}
void FileDownloader::download(QUrl url) { // <------ And its definition
QNetworkRequest request(url);
m_WebCtrl.get(request);
}
QByteArray FileDownloader::downloadedData() const {
return m_DownloadedData;
}
And then your on_pushButton_clicked will look like this:
void MainWindow::on_pushButton_clicked()
{
// pass to filedownloader to process
QUrl fileloc("http://www.test.com/test.jpg");
m_filedownloader.download(fileloc);
}