QT HTTP exercise-Create a UI program that can download URL resources and save it to a local directory

#include #include "mainwindow.h" int main (int argc, char *argv[]) {qapplication A (argc, argv);
    MainWindow W;
    
    W.show ();

return A.exec ();
} #ifndef mainwindow_h #define MAINWINDOW_H #include #include//① forward declaration class QFile;
Class qnetworkreply;


Class Qnetworkaccessmanager;

Namespace Ui {class MainWindow;
    } class Mainwindow:public Qmainwindow {q_object public:explicit MainWindow (qwidget *parent = 0);
    ~mainwindow ();         void startrequest (qurl URL);
    Declares a public response function to receive the URL private slots://③ declaration slot void httpfinished ();
    void Httpreadyread ();
    void Updatedataprogress (Qint64,qint64);

void on_pushbutton_clicked ();
    Private://② defines Qnetworkaccessmanager *manager;
    Ui::mainwindow *ui;
    Qnetworkreply *reply;
    Qurl URL;
QFile *file;


}; #endif//Mainwindow_h#include "mainwindow.h" #include "ui_mainwindow.h" #include #include #include #include mainwindo W::mainwindow (Qwidget *parent): QmaiNwindow (parent), UI (new Ui::mainwindow) {ui->setupui (this);  Manager = new Qnetworkaccessmanager (this);   Create a network Management instance Manager ui->progressbar->hide ();

Hide Progress bar} Mainwindow::~mainwindow () {Delete UI;}
    void mainwindow::startrequest (qurl url) {reply = Manager->get (qnetworkrequest (URL));
    Connect (reply,signal (Readyread ()), This,slot (Httpreadyread ()));
    Connect (reply,signal (downloadprogress (Qint64,qint64)), This,slot (Updatedataprogress (Qint64,qint64)));
Connect (reply,signal (finished ()), This,slot (httpfinished ()));
    }//Download complete, hide progress bar, close file void mainwindow::httpfinished () {ui->progressbar->hide ();
    File->flush ();
    File->close ();
    Reply->deletelater ();

    reply=0;
    Delete file;
file=0;

}//Read ready to read the file into the files in void Mainwindow::httpreadyread () {if (file) File->write (Reply->readall ());} During the download process, the activation progress bar dynamically shows void Mainwindow::updatedataprogress (Qint64 bytesread, Qint64 totalbytes) {ui->progressbar-≫setmaximum (totalbytes);
Ui->progressbar->setvalue (Bytesread);    } void Mainwindow::on_pushbutton_clicked () {Qdir *temp = new Qdir;
    Get the address of qdir, not copy a Qdir//determine if the folder exists bool exist = Temp->exists ("./download");
     if (exist) qmessagebox::warning (This,tr ("Creat folder"), TR ("The folder is exist!");    else {bool OK = Temp->mkdir ("./download"); Create if (OK) qmessagebox::warning when the folder does not exist (THIS,TR ("Creat folder"), tr ("creat the folder Successful")
        );
    }//Get URL address url from lineEdit = Ui->lineedit->text ();
    Qfileinfo info= (Url.path ());
        Qdebug () <open (qiodevice::writeonly)) {qdebug () << "File open error";
        Delete file;
        file=0;
    Return                     } startrequest (URL);          Get URL ui->progressbar->setvalue (0);               Set the progress bar value starting at 0 ui->progressbar->show (); Show Progress Bar}