Qt用Tcp 和Udp 传图片的例子，对于没做过这方面编程的朋友肯定很有帮助

/* * Copyright (c) 2006-2007, Johan Thelin * * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of APress nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ #include <QBuffer> #include <QImageReader> #include <QMessageBox> #include "clientdialog.h" ClientDialog::ClientDialog() : QDialog() { ui.setupUi( this ); connect( ui.getButton, SIGNAL(clicked()), this, SLOT(getClicked()) ); connect( &socket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(tcpError(QAbstractSocket::SocketError)) ); connect( &socket, SIGNAL(readyRead()), this, SLOT(tcpReady()) ); } void ClientDialog::getClicked() { ui.getButton->setEnabled( false ); ui.imageLabel->setPixmap( QPixmap() ); ui.imageLabel->setText( tr("<i>Getting image...</i>") ); dataSize = 0; socket.abort(); socket.connectToHost( ui.serverEdit->text(), 9876 ); } void ClientDialog::tcpReady() { if( dataSize == 0 ) { QDataStream stream( &socket ); stream.setVersion( QDataStream::Qt_4_0 ); if( socket.bytesAvailable() < sizeof(quint32) ) return; stream >> dataSize; } if( dataSize > socket.bytesAvailable() ) return; QByteArray array = socket.read( dataSize ); QBuffer buffer(&array); buffer.open( QIODevice::ReadOnly ); QImageReader reader(&buffer, "PNG"); QImage image = reader.read(); if( !image.isNull() ) { ui.imageLabel->setPixmap( QPixmap::fromImage( image ) ); ui.imageLabel->setText( tr("") ); } else { ui.imageLabel->setText( tr("<i>Invalid image received!</i>") ); } ui.getButton->setEnabled( true ); } void ClientDialog::tcpError( QAbstractSocket::SocketError error ) { if( error == QAbstractSocket::RemoteHostClosedError ) return; QMessageBox::warning( this, tr("Error"), tr("TCP error: %1").arg( socket.errorString() ) ); ui.imageLabel->setText( tr("<i>No Image</i>") ); ui.getButton->setEnabled( true ); }