QT---FTP练习，连接FTP服务器，浏览其中的文件，下载到本地目录中

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 
   
   
    
    
#include 
    
    
     
     
#include 
     
     
      
      
#include 
      
      
       
       
#include 
       
       
         MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); ui->progressBar->setValue(0); connect(ui->fileList,SIGNAL(itemActivated(QTreeWidgetItem*,int)),this,SLOT(processItem(QTreeWidgetItem*,int)) ); } MainWindow::~MainWindow() { delete ui; } void MainWindow::ftpCommandStarted(int) { int id=ftp->currentCommand(); switch (id) { case QFtp::ConnectToHost: ui->label->setText(tr("connecting to the qftp...")); break; case QFtp::Login: ui->label->setText(tr("logining ...")); break; case QFtp::Get: ui->label->setText(tr("loading ...")); break; case QFtp::Close: ui->label->setText(tr("run to close ...")); default: break; } } void MainWindow::ftpCommandFinished(int,bool error) { if(ftp->currentCommand()==QFtp::ConnectToHost){ if(error) ui->label->setText(tr("connection has found error: %1").arg(ftp->errorString())); else ui->label->setText(tr("connecting successful")); } else if(ftp->currentCommand()==QFtp::Login){ if(error) ui->label->setText(tr("login has found error: %1").arg(ftp->errorString())); else ui->label->setText(tr("login successful")); } else if(ftp->currentCommand()==QFtp::Get){ if(error) ui->label->setText(tr("load has found error: %1").arg(ftp->errorString())); else{ ui->label->setText(tr("load successful")); file->close(); } ui->downloadButton->setEnabled(true); } else if(ftp->currentCommand()==QFtp::List){ if(isDirectory.isEmpty()) { ui->fileList->addTopLevelItem(new QTreeWidgetItem(QStringList()< 
        
          fileList->setEnabled(false); ui->label->setText(tr("folder is empty")); } } else if(ftp->currentCommand()==QFtp::Close){ ui->label->setText(tr("closed")); } } void MainWindow::updateDataTransferProgress(qint64 readBytes, qint64 totalBytes) { ui->progressBar->setMaximum(totalBytes); ui->progressBar->setValue(readBytes); } void MainWindow::addToList(const QUrlInfo &urlInfo) { QTreeWidgetItem *item=new QTreeWidgetItem; item->setText(0,urlInfo.name()); item->setText(1,QString::number(urlInfo.size())); item->setText(2,urlInfo.owner()); item->setText(3,urlInfo.group()); item->setText(4,urlInfo.lastModified().toString("yyyy-MM-dd")); QPixmap pixmap; item->setIcon(0,pixmap); isDirectory[urlInfo.name()]=urlInfo.isDir(); ui->fileList->addTopLevelItem(item); if(! ui->fileList->currentItem()){ ui->fileList->setCurrentItem(ui->fileList->topLevelItem(0)); ui->fileList->setEnabled(true); } } void MainWindow::processItem(QTreeWidgetItem *item, int) { QString name=item->text(0); if(isDirectory.value(name)){ ui->fileList->clear(); isDirectory.clear(); currentPath+="/download"; currentPath+=name; ftp->cd(name); ftp->list(); ui->cdToParentButton->setEnabled(true); } } void MainWindow::on_connectButton_clicked() { ui->fileList->clear(); currentPath.clear(); isDirectory.clear(); ftp=new QFtp(this); connect(ftp,SIGNAL(commandStarted(int)),this,SLOT(ftpCommandStarted(int))); connect(ftp,SIGNAL(commandFinished(int,bool)),this,SLOT(ftpCommandFinished(int,bool))); connect(ftp,SIGNAL(listInfo(QUrlInfo)),this,SLOT(addToList(QUrlInfo))); connect(ftp,SIGNAL(dataTransferProgress(qint64,qint64)),this,SLOT(updateDataTransferProgress(qint64,qint64))); QString ftpServer = ui->ftpServerlineEdit->text(); QString userName = ui->userNamelineEdit->text(); QString passWord = ui->passWordlineEdit->text(); ftp->connectToHost(ftpServer,21); ftp->login(userName,passWord); } void MainWindow::on_cdToParentButton_clicked() { ui->fileList->clear(); isDirectory.clear(); currentPath=currentPath.left(currentPath.lastIndexOf('/')); if(currentPath.isEmpty()){ ui->cdToParentButton->setEnabled(false); ftp->cd("/"); }else{ ftp->cd(currentPath); } ftp->list(); } void MainWindow::on_downloadButton_clicked() { QDir *temp = new QDir; //获取QDir的地址，不是复制一个QDir //判断文件夹是否存在 bool exist = temp->exists("./download"); if(exist) QMessageBox::warning(this,tr("creat folder"),tr("The folder is exist!")); else { bool ok = temp->mkdir("./download"); //当文件夹不存在时进行创建 if(ok) QMessageBox::warning(this,tr("creat folder"),tr("Creat the folder successful")); } QString filename = ui->fileList->currentItem()->text(0); filename = "download\\"+filename; //文件保存在./download文件夹中 file = new QFile(filename); if(!file->open(QIODevice::WriteOnly)){ delete file; return ; } ui->downloadButton->setEnabled(false); ftp->get(ui->fileList->currentItem()->text(0),file); } #ifndef MAINWINDOW_H #define MAINWINDOW_H #include 
         
           #include 
          
            class QFtp; class QFile; class QUrlInfo; class QTreeWidgetItem; namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); private: Ui::MainWindow *ui; QFtp *ftp; //存储一个路径是否为目录信息 QHash 
           
             isDirectory; //存储现在的路径 QString currentPath; //表示下载的文件 QFile *file; signals: private slots: void ftpCommandStarted(int); void ftpCommandFinished(int,bool); //更新进度条 void updateDataTransferProgress(qint64,qint64); //将服务器上的文件添加到Tree Widget部件中 void addToList(const QUrlInfo &urlInfo); //双击一个目录时显示其内容 void processItem(QTreeWidgetItem* , int); void on_connectButton_clicked(); void on_cdToParentButton_clicked(); void on_downloadButton_clicked(); }; #endif // MAINWINDOW_H