这是获取网页来源的代码(C ++:Qt):
QString htmlString;
QEventLoop eventLoop;
QNetworkAccessManager mgr;
QObject::connect(&mgr, SIGNAL(finished(QNetworkReply*)), &eventLoop, SLOT(quit()));
QNetworkRequest req( QUrl( QString( "http://stackoverflow.com" ) ) );
QNetworkReply *reply = mgr.get(req);
eventLoop.exec();
htmlString = reply->readAll();
有没有办法获得带有进度条的网页来源?!
答案 0 :(得分:2)
为此写下特殊课程:
#ifndef DOWNLOADER_H
#define DOWNLOADER_H
#include <QObject>
#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkReply>
#include <QUrl>
#include <QDebug>
#include <QProgressBar>
class Downloader : public QObject
{
Q_OBJECT
public:
explicit Downloader(QObject *parent = 0);
void doDownload();
public slots:
void replyFinished (QNetworkReply *reply);
void updateDownloadProgress(qint64, qint64);
private:
QNetworkAccessManager *manager;
QProgressBar *bar;
};
#endif
.cpp的:
Downloader::Downloader(QObject *parent) :
QObject(parent)
{
}
void Downloader::doDownload()
{
manager = new QNetworkAccessManager(this);
connect(manager, SIGNAL(finished(QNetworkReply*)),
this, SLOT(replyFinished(QNetworkReply*)));
QNetworkReply * rep = manager->get(QNetworkRequest(QUrl("http://qt-project.org/")));
connect(rep, SIGNAL(downloadProgress(qint64, qint64)),
this, SLOT(updateDownloadProgress(qint64, qint64)));
bar = new QProgressBar;
bar->show();
}
void Downloader::replyFinished (QNetworkReply *reply)
{
if(reply->error())
{
qDebug() << "ERROR!";
qDebug() << reply->errorString();
}
else
{
qDebug() << reply->readAll();
}
reply->deleteLater();
}
void Downloader::updateDownloadProgress(qint64 read, qint64 total)
{
qDebug() << read << total;
bar->setMaximum(total);
bar->setValue(read);
}
用法:
Downloader down;
down.doDownload();
此处的主要想法是使用void QNetworkReply::downloadProgress(qint64 bytesReceived, qint64 bytesTotal) [signal]
获取进度并在QProgressBar
中显示此进展。
您可以使用当前的代码执行此操作而不使用类:
QString htmlString;
QEventLoop eventLoop;
QNetworkAccessManager mgr;
QObject::connect(&mgr, SIGNAL(finished(QNetworkReply*)), &eventLoop, SLOT(quit()));
QProgressBar *bar = new QProgressBar;
bar->show();
QNetworkRequest req( QUrl( QString( "http://stackoverflow.com" ) ) );
QNetworkReply *reply = mgr.get(req);
QObject::connect(reply,&QNetworkReply::downloadProgress,[=](qint64 bytesReceived, qint64 bytesTotal) {//with lambda
bar->setMaximum(bytesTotal);
bar->setValue(bytesReceived);
});
eventLoop.exec();
htmlString = reply->readAll();
qDebug() << htmlString;
我在这里使用了C++11
(CONFIG += c++11
到.pro
文件)和new syntax of signals and slots。