Linux窗口程序设计—Qt4精彩实例分析 第8章 网络与通信 源代码

#include "httpclient.h" HttpClient::HttpClient( QWidget *parent, Qt::WindowFlags f ) : QDialog( parent, f ) { QFont font("ZYSong18030",12); setFont(font); setWindowTitle(tr("Http Client")); urlLabel = new QLabel( this ); urlLabel->setText(tr("Url:")); urlLineEdit = new QLineEdit( this ); progressBar = new QProgressBar( this ); downloadPushButton = new QPushButton( this); downloadPushButton->setText( tr( "Download" ) ); cancelPushButton = new QPushButton( this); cancelPushButton->setText( tr( "Cancel" ) ); exitPushButton = new QPushButton( this); exitPushButton->setText( tr( "Exit" ) ); QHBoxLayout *hbLayout1 = new QHBoxLayout(); hbLayout1->addWidget( urlLabel ); hbLayout1->addWidget( urlLineEdit ); QHBoxLayout *hbLayout2 = new QHBoxLayout(); hbLayout2->addWidget( progressBar ); QHBoxLayout *hbLayout3 = new QHBoxLayout(); hbLayout3->addWidget( downloadPushButton ); hbLayout3->addWidget( cancelPushButton ); hbLayout3->addWidget( exitPushButton ); QVBoxLayout *vbLayout = new QVBoxLayout( this ); vbLayout->addLayout( hbLayout1 ); vbLayout->addLayout( hbLayout2 ); vbLayout->addLayout( hbLayout3 ); httpClient = new QHttp(this); connect(httpClient, SIGNAL(requestFinished(int, bool)),this, SLOT(httpRequestFinished(int, bool))); connect(httpClient, SIGNAL(dataReadProgress(int, int)),this, SLOT(httpDataReadProgress(int, int))); connect(httpClient, SIGNAL(responseHeaderReceived(const QHttpResponseHeader &)),this, SLOT(httpResponseHeaderReceived(const QHttpResponseHeader &))); connect(downloadPushButton,SIGNAL(clicked()),this,SLOT(slotDownload())); connect(cancelPushButton,SIGNAL(clicked()),this,SLOT(slotCancel())); connect(exitPushButton,SIGNAL(clicked()),this,SLOT(slotExit())); cancelPushButton->setEnabled(false); } HttpClient::~HttpClient() { } void HttpClient::slotDownload() { QUrl url(urlLineEdit->text()); QFileInfo fileInfo(url.path()); QString fileName = fileInfo.fileName(); if (QFile::exists(fileName)) { QMessageBox::information(this, tr("Error"),tr("File already exists!")); return; } file = new QFile(fileName); if (!file->open(QIODevice::WriteOnly)) { QMessageBox::information(this, tr("Error"),tr("Save file error!")); delete file; file = 0; return; } httpClient->setHost(url.host(), url.port() != -1 ? url.port() : 80); if (!url.userName().isEmpty()) { httpClient->setUser(url.userName(), url.password()); } httpRequestAborted = false; requestId = httpClient->get(url.path(), file); progressBar->reset(); downloadPushButton->setEnabled(false); cancelPushButton->setEnabled(true); } void HttpClient::slotCancel() { httpRequestAborted = true; httpClient->abort(); downloadPushButton->setEnabled(true); cancelPushButton->setEnabled(false); } void HttpClient::slotExit() { accept(); } void HttpClient::httpRequestFinished(int id, bool error) { if (httpRequestAborted) { if (file) { file->close(); file->remove(); delete file; file = 0; } progressBar->reset(); return; } if (id == requestId) { progressBar->reset(); file->close(); if (error) { file->remove(); QMessageBox::information(this, tr("Error"),tr("Download failed!")); } downloadPushButton->setEnabled(true); cancelPushButton->setEnabled(false); delete file; file = 0; } } void HttpClient::httpDataReadProgress(int done, int total) { progressBar->setMaximum(total); progressBar->setValue(done); } void HttpClient::httpResponseHeaderReceived(const QHttpResponseHeader &responseHeader) { if (responseHeader.statusCode() != 200) { QMessageBox::information(this, tr("Error"), tr("Download error!")); httpRequestAborted = true; progressBar->reset(); httpClient->abort(); return; } }