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How to save a table in a file

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  • jsulmJ jsulm

    @Daesos Try calling http://doc.qt.io/qt-5/qtextstream.html#flush before closing the file

    D Offline
    D Offline
    Daesos
    wrote on last edited by
    #11

    @jsulm Already did, and nothing changed.

    jsulmJ 1 Reply Last reply
    0
    • D Daesos

      @jsulm Already did, and nothing changed.

      jsulmJ Offline
      jsulmJ Offline
      jsulm
      Lifetime Qt Champion
      wrote on last edited by
      #12

      @Daesos Last idea I have: is it possible that you open same file somewhere else in your app, or that there is still an instance of your app running?
      Oh, one more idea: try to write the file using an absolute path to some other location.

      https://forum.qt.io/topic/113070/qt-code-of-conduct

      D 1 Reply Last reply
      0
      • jsulmJ jsulm

        @Daesos Last idea I have: is it possible that you open same file somewhere else in your app, or that there is still an instance of your app running?
        Oh, one more idea: try to write the file using an absolute path to some other location.

        D Offline
        D Offline
        Daesos
        wrote on last edited by Daesos
        #13

        @jsulm I checked and there is no other instance opened. Also, I used another path. The program created the file.csv (empty), then quitted. Application Output: "The program has unexpectedly finished."

        Since I don't know if I have mistaken something I will post all the mainwindow.cpp code:

        #include "mainwindow.h"
        #include "ui_mainwindow.h"
        #include <QFileDialog>
        #include <QFileInfo>
        #include <QTimer>
        #include <QDateTime>
        #include <QFile>
        #include <QTextStream>
        
        MainWindow::MainWindow(QWidget *parent) :
            QMainWindow(parent),
            ui(new Ui::MainWindow)
        {
            ui->setupUi(this);
        
            setWindowTitle("DirectoryMonitor");
            ui->tableWidget->setColumnCount(4);
            ui->tableWidget->setHorizontalHeaderLabels(QStringList() << "" << "Filename" << "Event" << "Time");
        
            f_name = "log_activity.csv";
        }
        
        MainWindow::~MainWindow()
        {
            delete ui;
        }
        
        void MainWindow::on_pushButton_clicked()
        {
            ui->tableWidget->clearContents();
            path = QFileDialog::getExistingDirectory(this, tr("Open Directory"), ".", QFileDialog::ShowDirsOnly | QFileDialog::DontResolveSymlinks);
            ui->lineEdit->setText(path);
        
        QDir dir(path);
        
        dir.setFilter(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot);
        dir.setSorting(QDir::Time);
        list = dir.entryInfoList();
        
        for(int i = 0; i < list.size(); ++i){
                ui->tableWidget->insertRow(ui->tableWidget->rowCount());
                ui->tableWidget->setItem(i, 1, new QTableWidgetItem(list.at(i).fileName()));
                ui->tableWidget->setItem(i, 3, new QTableWidgetItem(list.at(i).lastModified().toString()));
        }
        
        int count = 0;
        
        for(int i = 0; i < ui->tableWidget->rowCount(); ++i){
            QTableWidgetItem *itm = ui->tableWidget->item(i, 1);
            if(itm != 0)
               ++count;
        }
        //rimuovi righe vuote
        ui->tableWidget->setRowCount(count);
        
        QTimer *time = new QTimer(this);
        
        connect(time, SIGNAL(timeout()), this, SLOT(changes()));
        time->start(3000);
        }
        
        void MainWindow::changes()
        {
        QDir dir(path);
        dir.setFilter(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot);
        dir.setSorting(QDir::Time);
        
        QFileInfoList newlist = dir.entryInfoList();
        
        int index_delete = -1;
        
        //caso modified e delete file
        for(int i = 0; i < list.size(); ++i){
            int count = 0;
            for(int j = 0; j < newlist.size(); ++j){
                if(list.at(i).fileName() == newlist.at(j).fileName()){
                    ++count;
                    if(list.at(i).lastModified() != newlist.at(j).lastModified()){
                        QTableWidgetItem *itm = new QTableWidgetItem("");
                        itm->setBackground(QColor(109, 158, 235));
                        ui->tableWidget->setItem(i, 0, itm);
                        ui->tableWidget->setItem(i, 2, new QTableWidgetItem("Modified"));
                        ui->tableWidget->setItem(i, 3, new QTableWidgetItem(newlist.at(j).lastModified().toString()));
                    }
                }
            }
            if(count == 0){
                index_delete = i;
            }
        }
        
        if(index_delete != -1){
            QTableWidgetItem *itm = new QTableWidgetItem("");
            itm->setBackground(QColor(224, 102, 99));
            ui->tableWidget->setItem(index_delete, 0, itm);
            if(ui->tableWidget->item(index_delete, 2)->text() != "Deleted")
                ui->tableWidget->setItem(index_delete, 3, new QTableWidgetItem(QDateTime::currentDateTime().toString()));
            ui->tableWidget->setItem(index_delete, 2, new QTableWidgetItem("Deleted"));
        }
        
        //caso new file
        int index_new = -1;
        
        for(int i = 0; i < newlist.size(); ++i){
            int count = 0;
            for(int j = 0; (j < list.size() && count == 0); ++j){
                if(newlist.at(i).fileName() == list.at(j).fileName())
                    ++count;
            }
            if(count == 0)
                index_new = i;
        }
        
        if(index_new != -1){
            ui->tableWidget->insertRow(ui->tableWidget->rowCount());
            QTableWidgetItem *itm = new QTableWidgetItem("");
            itm->setBackground(QColor(148, 195, 123));
            ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 0, itm);
            ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 1, new QTableWidgetItem(newlist.at(index_new).fileName()));
            ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 2, new QTableWidgetItem("Created"));
            ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 3, new QTableWidgetItem(newlist.at(index_new).lastModified().toString()));
            list.append(newlist.at(index_new));
        }
        }
        void MainWindow::on_pushButton_2_clicked()
        {
        QFile csv(f_name);
        
        if(!csv.open(QFile::WriteOnly))
            return;
        
        QTextStream out(&csv);
        
        for(int i = 0; i < ui->tableWidget->rowCount(); ++i)
            for (int j = 1; j < ui->tableWidget->columnCount(); j++){
                QString txt(ui->tableWidget->item(i, j)->text());
                out<<txt;
            }
        out.flush();
        csv.close();
        }
        

        Sorry for the indentation.
        This is the declaration of the global variables in mainwindow.h

        QString path, f_name;
        QFileInfoList list;
        
        jsulmJ J.HilkJ JonBJ 3 Replies Last reply
        0
        • D Daesos

          @jsulm I checked and there is no other instance opened. Also, I used another path. The program created the file.csv (empty), then quitted. Application Output: "The program has unexpectedly finished."

          Since I don't know if I have mistaken something I will post all the mainwindow.cpp code:

          #include "mainwindow.h"
          #include "ui_mainwindow.h"
          #include <QFileDialog>
          #include <QFileInfo>
          #include <QTimer>
          #include <QDateTime>
          #include <QFile>
          #include <QTextStream>
          
          MainWindow::MainWindow(QWidget *parent) :
              QMainWindow(parent),
              ui(new Ui::MainWindow)
          {
              ui->setupUi(this);
          
              setWindowTitle("DirectoryMonitor");
              ui->tableWidget->setColumnCount(4);
              ui->tableWidget->setHorizontalHeaderLabels(QStringList() << "" << "Filename" << "Event" << "Time");
          
              f_name = "log_activity.csv";
          }
          
          MainWindow::~MainWindow()
          {
              delete ui;
          }
          
          void MainWindow::on_pushButton_clicked()
          {
              ui->tableWidget->clearContents();
              path = QFileDialog::getExistingDirectory(this, tr("Open Directory"), ".", QFileDialog::ShowDirsOnly | QFileDialog::DontResolveSymlinks);
              ui->lineEdit->setText(path);
          
          QDir dir(path);
          
          dir.setFilter(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot);
          dir.setSorting(QDir::Time);
          list = dir.entryInfoList();
          
          for(int i = 0; i < list.size(); ++i){
                  ui->tableWidget->insertRow(ui->tableWidget->rowCount());
                  ui->tableWidget->setItem(i, 1, new QTableWidgetItem(list.at(i).fileName()));
                  ui->tableWidget->setItem(i, 3, new QTableWidgetItem(list.at(i).lastModified().toString()));
          }
          
          int count = 0;
          
          for(int i = 0; i < ui->tableWidget->rowCount(); ++i){
              QTableWidgetItem *itm = ui->tableWidget->item(i, 1);
              if(itm != 0)
                 ++count;
          }
          //rimuovi righe vuote
          ui->tableWidget->setRowCount(count);
          
          QTimer *time = new QTimer(this);
          
          connect(time, SIGNAL(timeout()), this, SLOT(changes()));
          time->start(3000);
          }
          
          void MainWindow::changes()
          {
          QDir dir(path);
          dir.setFilter(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot);
          dir.setSorting(QDir::Time);
          
          QFileInfoList newlist = dir.entryInfoList();
          
          int index_delete = -1;
          
          //caso modified e delete file
          for(int i = 0; i < list.size(); ++i){
              int count = 0;
              for(int j = 0; j < newlist.size(); ++j){
                  if(list.at(i).fileName() == newlist.at(j).fileName()){
                      ++count;
                      if(list.at(i).lastModified() != newlist.at(j).lastModified()){
                          QTableWidgetItem *itm = new QTableWidgetItem("");
                          itm->setBackground(QColor(109, 158, 235));
                          ui->tableWidget->setItem(i, 0, itm);
                          ui->tableWidget->setItem(i, 2, new QTableWidgetItem("Modified"));
                          ui->tableWidget->setItem(i, 3, new QTableWidgetItem(newlist.at(j).lastModified().toString()));
                      }
                  }
              }
              if(count == 0){
                  index_delete = i;
              }
          }
          
          if(index_delete != -1){
              QTableWidgetItem *itm = new QTableWidgetItem("");
              itm->setBackground(QColor(224, 102, 99));
              ui->tableWidget->setItem(index_delete, 0, itm);
              if(ui->tableWidget->item(index_delete, 2)->text() != "Deleted")
                  ui->tableWidget->setItem(index_delete, 3, new QTableWidgetItem(QDateTime::currentDateTime().toString()));
              ui->tableWidget->setItem(index_delete, 2, new QTableWidgetItem("Deleted"));
          }
          
          //caso new file
          int index_new = -1;
          
          for(int i = 0; i < newlist.size(); ++i){
              int count = 0;
              for(int j = 0; (j < list.size() && count == 0); ++j){
                  if(newlist.at(i).fileName() == list.at(j).fileName())
                      ++count;
              }
              if(count == 0)
                  index_new = i;
          }
          
          if(index_new != -1){
              ui->tableWidget->insertRow(ui->tableWidget->rowCount());
              QTableWidgetItem *itm = new QTableWidgetItem("");
              itm->setBackground(QColor(148, 195, 123));
              ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 0, itm);
              ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 1, new QTableWidgetItem(newlist.at(index_new).fileName()));
              ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 2, new QTableWidgetItem("Created"));
              ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 3, new QTableWidgetItem(newlist.at(index_new).lastModified().toString()));
              list.append(newlist.at(index_new));
          }
          }
          void MainWindow::on_pushButton_2_clicked()
          {
          QFile csv(f_name);
          
          if(!csv.open(QFile::WriteOnly))
              return;
          
          QTextStream out(&csv);
          
          for(int i = 0; i < ui->tableWidget->rowCount(); ++i)
              for (int j = 1; j < ui->tableWidget->columnCount(); j++){
                  QString txt(ui->tableWidget->item(i, j)->text());
                  out<<txt;
              }
          out.flush();
          csv.close();
          }
          

          Sorry for the indentation.
          This is the declaration of the global variables in mainwindow.h

          QString path, f_name;
          QFileInfoList list;
          
          jsulmJ Offline
          jsulmJ Offline
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #14

          @Daesos Start your app with debugger (F5) and when it crashes check the stack trace to see where it crashes (use debug build of your app).

          https://forum.qt.io/topic/113070/qt-code-of-conduct

          1 Reply Last reply
          0
          • D Daesos

            @jsulm I checked and there is no other instance opened. Also, I used another path. The program created the file.csv (empty), then quitted. Application Output: "The program has unexpectedly finished."

            Since I don't know if I have mistaken something I will post all the mainwindow.cpp code:

            #include "mainwindow.h"
            #include "ui_mainwindow.h"
            #include <QFileDialog>
            #include <QFileInfo>
            #include <QTimer>
            #include <QDateTime>
            #include <QFile>
            #include <QTextStream>
            
            MainWindow::MainWindow(QWidget *parent) :
                QMainWindow(parent),
                ui(new Ui::MainWindow)
            {
                ui->setupUi(this);
            
                setWindowTitle("DirectoryMonitor");
                ui->tableWidget->setColumnCount(4);
                ui->tableWidget->setHorizontalHeaderLabels(QStringList() << "" << "Filename" << "Event" << "Time");
            
                f_name = "log_activity.csv";
            }
            
            MainWindow::~MainWindow()
            {
                delete ui;
            }
            
            void MainWindow::on_pushButton_clicked()
            {
                ui->tableWidget->clearContents();
                path = QFileDialog::getExistingDirectory(this, tr("Open Directory"), ".", QFileDialog::ShowDirsOnly | QFileDialog::DontResolveSymlinks);
                ui->lineEdit->setText(path);
            
            QDir dir(path);
            
            dir.setFilter(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot);
            dir.setSorting(QDir::Time);
            list = dir.entryInfoList();
            
            for(int i = 0; i < list.size(); ++i){
                    ui->tableWidget->insertRow(ui->tableWidget->rowCount());
                    ui->tableWidget->setItem(i, 1, new QTableWidgetItem(list.at(i).fileName()));
                    ui->tableWidget->setItem(i, 3, new QTableWidgetItem(list.at(i).lastModified().toString()));
            }
            
            int count = 0;
            
            for(int i = 0; i < ui->tableWidget->rowCount(); ++i){
                QTableWidgetItem *itm = ui->tableWidget->item(i, 1);
                if(itm != 0)
                   ++count;
            }
            //rimuovi righe vuote
            ui->tableWidget->setRowCount(count);
            
            QTimer *time = new QTimer(this);
            
            connect(time, SIGNAL(timeout()), this, SLOT(changes()));
            time->start(3000);
            }
            
            void MainWindow::changes()
            {
            QDir dir(path);
            dir.setFilter(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot);
            dir.setSorting(QDir::Time);
            
            QFileInfoList newlist = dir.entryInfoList();
            
            int index_delete = -1;
            
            //caso modified e delete file
            for(int i = 0; i < list.size(); ++i){
                int count = 0;
                for(int j = 0; j < newlist.size(); ++j){
                    if(list.at(i).fileName() == newlist.at(j).fileName()){
                        ++count;
                        if(list.at(i).lastModified() != newlist.at(j).lastModified()){
                            QTableWidgetItem *itm = new QTableWidgetItem("");
                            itm->setBackground(QColor(109, 158, 235));
                            ui->tableWidget->setItem(i, 0, itm);
                            ui->tableWidget->setItem(i, 2, new QTableWidgetItem("Modified"));
                            ui->tableWidget->setItem(i, 3, new QTableWidgetItem(newlist.at(j).lastModified().toString()));
                        }
                    }
                }
                if(count == 0){
                    index_delete = i;
                }
            }
            
            if(index_delete != -1){
                QTableWidgetItem *itm = new QTableWidgetItem("");
                itm->setBackground(QColor(224, 102, 99));
                ui->tableWidget->setItem(index_delete, 0, itm);
                if(ui->tableWidget->item(index_delete, 2)->text() != "Deleted")
                    ui->tableWidget->setItem(index_delete, 3, new QTableWidgetItem(QDateTime::currentDateTime().toString()));
                ui->tableWidget->setItem(index_delete, 2, new QTableWidgetItem("Deleted"));
            }
            
            //caso new file
            int index_new = -1;
            
            for(int i = 0; i < newlist.size(); ++i){
                int count = 0;
                for(int j = 0; (j < list.size() && count == 0); ++j){
                    if(newlist.at(i).fileName() == list.at(j).fileName())
                        ++count;
                }
                if(count == 0)
                    index_new = i;
            }
            
            if(index_new != -1){
                ui->tableWidget->insertRow(ui->tableWidget->rowCount());
                QTableWidgetItem *itm = new QTableWidgetItem("");
                itm->setBackground(QColor(148, 195, 123));
                ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 0, itm);
                ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 1, new QTableWidgetItem(newlist.at(index_new).fileName()));
                ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 2, new QTableWidgetItem("Created"));
                ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 3, new QTableWidgetItem(newlist.at(index_new).lastModified().toString()));
                list.append(newlist.at(index_new));
            }
            }
            void MainWindow::on_pushButton_2_clicked()
            {
            QFile csv(f_name);
            
            if(!csv.open(QFile::WriteOnly))
                return;
            
            QTextStream out(&csv);
            
            for(int i = 0; i < ui->tableWidget->rowCount(); ++i)
                for (int j = 1; j < ui->tableWidget->columnCount(); j++){
                    QString txt(ui->tableWidget->item(i, j)->text());
                    out<<txt;
                }
            out.flush();
            csv.close();
            }
            

            Sorry for the indentation.
            This is the declaration of the global variables in mainwindow.h

            QString path, f_name;
            QFileInfoList list;
            
            J.HilkJ Offline
            J.HilkJ Offline
            J.Hilk
            Moderators
            wrote on last edited by
            #15

            @Daesos
            Going through your code, I noticed, you're mixing postfix, prefix in your nested loop to access the Tablewidget Item. I would search there for an out of bounds error.


            Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


            Q: What's that?
            A: It's blue light.
            Q: What does it do?
            A: It turns blue.

            1 Reply Last reply
            1
            • D Daesos

              @jsulm I checked and there is no other instance opened. Also, I used another path. The program created the file.csv (empty), then quitted. Application Output: "The program has unexpectedly finished."

              Since I don't know if I have mistaken something I will post all the mainwindow.cpp code:

              #include "mainwindow.h"
              #include "ui_mainwindow.h"
              #include <QFileDialog>
              #include <QFileInfo>
              #include <QTimer>
              #include <QDateTime>
              #include <QFile>
              #include <QTextStream>
              
              MainWindow::MainWindow(QWidget *parent) :
                  QMainWindow(parent),
                  ui(new Ui::MainWindow)
              {
                  ui->setupUi(this);
              
                  setWindowTitle("DirectoryMonitor");
                  ui->tableWidget->setColumnCount(4);
                  ui->tableWidget->setHorizontalHeaderLabels(QStringList() << "" << "Filename" << "Event" << "Time");
              
                  f_name = "log_activity.csv";
              }
              
              MainWindow::~MainWindow()
              {
                  delete ui;
              }
              
              void MainWindow::on_pushButton_clicked()
              {
                  ui->tableWidget->clearContents();
                  path = QFileDialog::getExistingDirectory(this, tr("Open Directory"), ".", QFileDialog::ShowDirsOnly | QFileDialog::DontResolveSymlinks);
                  ui->lineEdit->setText(path);
              
              QDir dir(path);
              
              dir.setFilter(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot);
              dir.setSorting(QDir::Time);
              list = dir.entryInfoList();
              
              for(int i = 0; i < list.size(); ++i){
                      ui->tableWidget->insertRow(ui->tableWidget->rowCount());
                      ui->tableWidget->setItem(i, 1, new QTableWidgetItem(list.at(i).fileName()));
                      ui->tableWidget->setItem(i, 3, new QTableWidgetItem(list.at(i).lastModified().toString()));
              }
              
              int count = 0;
              
              for(int i = 0; i < ui->tableWidget->rowCount(); ++i){
                  QTableWidgetItem *itm = ui->tableWidget->item(i, 1);
                  if(itm != 0)
                     ++count;
              }
              //rimuovi righe vuote
              ui->tableWidget->setRowCount(count);
              
              QTimer *time = new QTimer(this);
              
              connect(time, SIGNAL(timeout()), this, SLOT(changes()));
              time->start(3000);
              }
              
              void MainWindow::changes()
              {
              QDir dir(path);
              dir.setFilter(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot);
              dir.setSorting(QDir::Time);
              
              QFileInfoList newlist = dir.entryInfoList();
              
              int index_delete = -1;
              
              //caso modified e delete file
              for(int i = 0; i < list.size(); ++i){
                  int count = 0;
                  for(int j = 0; j < newlist.size(); ++j){
                      if(list.at(i).fileName() == newlist.at(j).fileName()){
                          ++count;
                          if(list.at(i).lastModified() != newlist.at(j).lastModified()){
                              QTableWidgetItem *itm = new QTableWidgetItem("");
                              itm->setBackground(QColor(109, 158, 235));
                              ui->tableWidget->setItem(i, 0, itm);
                              ui->tableWidget->setItem(i, 2, new QTableWidgetItem("Modified"));
                              ui->tableWidget->setItem(i, 3, new QTableWidgetItem(newlist.at(j).lastModified().toString()));
                          }
                      }
                  }
                  if(count == 0){
                      index_delete = i;
                  }
              }
              
              if(index_delete != -1){
                  QTableWidgetItem *itm = new QTableWidgetItem("");
                  itm->setBackground(QColor(224, 102, 99));
                  ui->tableWidget->setItem(index_delete, 0, itm);
                  if(ui->tableWidget->item(index_delete, 2)->text() != "Deleted")
                      ui->tableWidget->setItem(index_delete, 3, new QTableWidgetItem(QDateTime::currentDateTime().toString()));
                  ui->tableWidget->setItem(index_delete, 2, new QTableWidgetItem("Deleted"));
              }
              
              //caso new file
              int index_new = -1;
              
              for(int i = 0; i < newlist.size(); ++i){
                  int count = 0;
                  for(int j = 0; (j < list.size() && count == 0); ++j){
                      if(newlist.at(i).fileName() == list.at(j).fileName())
                          ++count;
                  }
                  if(count == 0)
                      index_new = i;
              }
              
              if(index_new != -1){
                  ui->tableWidget->insertRow(ui->tableWidget->rowCount());
                  QTableWidgetItem *itm = new QTableWidgetItem("");
                  itm->setBackground(QColor(148, 195, 123));
                  ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 0, itm);
                  ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 1, new QTableWidgetItem(newlist.at(index_new).fileName()));
                  ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 2, new QTableWidgetItem("Created"));
                  ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 3, new QTableWidgetItem(newlist.at(index_new).lastModified().toString()));
                  list.append(newlist.at(index_new));
              }
              }
              void MainWindow::on_pushButton_2_clicked()
              {
              QFile csv(f_name);
              
              if(!csv.open(QFile::WriteOnly))
                  return;
              
              QTextStream out(&csv);
              
              for(int i = 0; i < ui->tableWidget->rowCount(); ++i)
                  for (int j = 1; j < ui->tableWidget->columnCount(); j++){
                      QString txt(ui->tableWidget->item(i, j)->text());
                      out<<txt;
                  }
              out.flush();
              csv.close();
              }
              

              Sorry for the indentation.
              This is the declaration of the global variables in mainwindow.h

              QString path, f_name;
              QFileInfoList list;
              
              JonBJ Offline
              JonBJ Offline
              JonB
              wrote on last edited by JonB
              #16

              @Daesos
              If you're still having problems with the file (once you've solved the "crash"), try replacing your QFile with a QString, and use https://doc.qt.io/Qt-5/qtextstream.html#QTextStream-3. You should be successfully building up the string of the file content. If that doesn't work, nor will write to file.

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              • D Offline
                D Offline
                Daesos
                wrote on last edited by Daesos
                #17

                I used debugger and when i click on pushButton_2 (save on interface) it returns a Segmentation Fault at "QTableWidgetItem::text".
                @J.Hilk, I didn't even notice. I edited the increment.

                Segmentation Fault occurs when I try to access to a NULL pointer, right? So, it might be out of bound.

                JonBJ 1 Reply Last reply
                0
                • D Daesos

                  I used debugger and when i click on pushButton_2 (save on interface) it returns a Segmentation Fault at "QTableWidgetItem::text".
                  @J.Hilk, I didn't even notice. I edited the increment.

                  Segmentation Fault occurs when I try to access to a NULL pointer, right? So, it might be out of bound.

                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by JonB
                  #18

                  @Daesos
                  I don't see save_button in the code you've posted?

                  I notice you have:

                                  ui->tableWidget->setItem(i, 0, itm);
                                  ui->tableWidget->setItem(i, 2, new QTableWidgetItem("Modified"));
                                  ui->tableWidget->setItem(i, 3, new QTableWidgetItem(newlist.at(j).lastModified().toString()));
                  

                  Where do you setItem() on i, 1 ?

                  for(int i = 0; i < ui->tableWidget->rowCount(); ++i)
                      for (int j = 1; j < ui->tableWidget->columnCount(); j++){
                          QString txt(ui->tableWidget->item(i, j)->text());
                          out<<txt;
                      }
                  

                  Check your accesses on every i, j here. Somewhere you do not have an item at item(i, j)!

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                  • D Offline
                    D Offline
                    Daesos
                    wrote on last edited by Daesos
                    #19

                    I've edited the increment:

                       for(int i = 0; i < ui->tableWidget->rowCount(); ++i)
                           for (int j = 1; j < ui->tableWidget->columnCount(); ++j)
                               out<<ui->tableWidget->item(i, j)->text();
                    

                    @JonB said in How to save a table in a file:

                    @Daesos

                    I notice you have:

                                    ui->tableWidget->setItem(i, 0, itm);
                                    ui->tableWidget->setItem(i, 2, new QTableWidgetItem("Modified"));
                                    ui->tableWidget->setItem(i, 3, new QTableWidgetItem(newlist.at(j).lastModified().toString()));
                    

                    Where do you setItem() on i, 1 ?

                    I've inizialized item at (i, 1) before. Once inizialized the name of the file must not be modified. So I didn't use setItem on i, 1 again.

                    @Daesos
                    ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 1, new QTableWidgetItem(newlist.at(index_new).fileName()));

                    J.HilkJ 1 Reply Last reply
                    0
                    • D Daesos

                      I've edited the increment:

                         for(int i = 0; i < ui->tableWidget->rowCount(); ++i)
                             for (int j = 1; j < ui->tableWidget->columnCount(); ++j)
                                 out<<ui->tableWidget->item(i, j)->text();
                      

                      @JonB said in How to save a table in a file:

                      @Daesos

                      I notice you have:

                                      ui->tableWidget->setItem(i, 0, itm);
                                      ui->tableWidget->setItem(i, 2, new QTableWidgetItem("Modified"));
                                      ui->tableWidget->setItem(i, 3, new QTableWidgetItem(newlist.at(j).lastModified().toString()));
                      

                      Where do you setItem() on i, 1 ?

                      I've inizialized item at (i, 1) before. Once inizialized the name of the file must not be modified. So I didn't use setItem on i, 1 again.

                      @Daesos
                      ui->tableWidget->setItem(ui->tableWidget->rowCount() - 1, 1, new QTableWidgetItem(newlist.at(index_new).fileName()));

                      J.HilkJ Offline
                      J.HilkJ Offline
                      J.Hilk
                      Moderators
                      wrote on last edited by
                      #20

                      @Daesos said in How to save a table in a file:

                      for(int i = 0; i < ui->tableWidget->rowCount(); ++i)
                      for (int j = 1; j < ui->tableWidget->columnCount(); ++j)
                      out<<ui->tableWidget->item(i, j)->text();

                      Maybe it's time to #include good old <QDebug>

                      for(int i = 0; i < ui->tableWidget->rowCount(); ++i)
                             for (int j = 1; j < ui->tableWidget->columnCount(); ++j){
                                 qDebug() << i << "of" << ui->tableWidget->rowCount() << endl
                                                   << j << "of" << ui->tableWidget->columnCount();
                                 out<<ui->tableWidget->item(i, j)->text();
                                 qDebug() << QString("Found text at %1 | %2").arg(i).arg(j);
                             }
                      

                      Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                      Q: What's that?
                      A: It's blue light.
                      Q: What does it do?
                      A: It turns blue.

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                      • VRoninV Offline
                        VRoninV Offline
                        VRonin
                        wrote on last edited by VRonin
                        #21

                        Replace out<<ui->tableWidget->item(i, j)->text(); with out<<ui->tableWidget->model()->index(i, j).data().tostring(); to prevent segfaults

                        The problems I highlighted are still present though

                        @VRonin said in How to save a table in a file:

                        In your code above you are not:

                        • Writing any new line to separate rows.
                        • Writing any column separator
                        • Escaping column separators inside the data

                        "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                        ~Napoleon Bonaparte

                        On a crusade to banish setIndexWidget() from the holy land of Qt

                        D 1 Reply Last reply
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                        • VRoninV VRonin

                          Replace out<<ui->tableWidget->item(i, j)->text(); with out<<ui->tableWidget->model()->index(i, j).data().tostring(); to prevent segfaults

                          The problems I highlighted are still present though

                          @VRonin said in How to save a table in a file:

                          In your code above you are not:

                          • Writing any new line to separate rows.
                          • Writing any column separator
                          • Escaping column separators inside the data
                          D Offline
                          D Offline
                          Daesos
                          wrote on last edited by Daesos
                          #22

                          @VRonin In a previous version I've added both ";" and "\n", but I forgot to write them again.
                          However I forgot one case: what happen if I did not create/delete/modify any file, folder, or other?
                          The cells (i, 2) might be empty and here is where the program fails.
                          I resolved by editing some code:

                          void MainWindow::on_pushButton_2_clicked()
                          {
                          QFile csv(f_name);
                          
                          if(!csv.open(QFile::WriteOnly))
                              return;
                          
                          QTextStream out(&csv);
                          int tmp_column = 0;
                          
                          for(int i = 0; i < ui->tableWidget->rowCount(); ++i){
                              for (int j = 1; j < ui->tableWidget->columnCount(); ++j){
                                  if(ui->tableWidget->item(i, j) != 0)
                                      out<<ui->tableWidget->item(i, j)->text();
                                      out<<";";
                                      tmp_column = j;
                              }
                              if(ui->tableWidget->item(i, tmp_column) != 0)
                                  out<<"\n";
                          }
                          
                          out.flush();
                          csv.close();
                          }
                          

                          It may not be quite good-looking but it works:

                          0_1531227135676_6d7d870f-2968-47b7-8941-b6ffbaac0431-image.png

                          I've also prevented segmentation faults like this for example:

                          ui->tableWidget->setItem(index_delete, 0, itm);
                              if(ui->tableWidget->item(index_delete, 2) != 0 && ui->tableWidget->item(index_delete, 2)->text() != "Deleted")
                                  ui->tableWidget->setItem(index_delete, 3, new QTableWidgetItem(QDateTime::currentDateTime().toString()));
                          
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                          0
                          • VRoninV Offline
                            VRoninV Offline
                            VRonin
                            wrote on last edited by VRonin
                            #23

                            Try naming a folder Ugly; Name and save your model

                            "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                            ~Napoleon Bonaparte

                            On a crusade to banish setIndexWidget() from the holy land of Qt

                            D VRoninV 2 Replies Last reply
                            1
                            • VRoninV VRonin

                              Try naming a folder Ugly; Name and save your model

                              D Offline
                              D Offline
                              Daesos
                              wrote on last edited by
                              #24

                              @VRonin You got me, this is another case to write.

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                              • VRoninV VRonin

                                Try naming a folder Ugly; Name and save your model

                                VRoninV Offline
                                VRoninV Offline
                                VRonin
                                wrote on last edited by VRonin
                                #25

                                P.S.
                                new QTableWidgetItem(QDateTime::currentDateTime().toString()) see https://bugreports.qt.io/browse/QTBUG-65555

                                this should be separated in 3 lines:

                                QTableWidgetItem* tableItem = new QTableWidgetItem;
                                tableItem->setData(Qt::EditRole,QDateTime::currentDateTime());
                                ui->tableWidget->setItem(index_delete, 3,tableItem);
                                

                                "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                                ~Napoleon Bonaparte

                                On a crusade to banish setIndexWidget() from the holy land of Qt

                                1 Reply Last reply
                                2
                                • D Offline
                                  D Offline
                                  Daesos
                                  wrote on last edited by Daesos
                                  #26

                                  Say I want to order the items of the table by name or date once I push Save, but without sorting the table itself (just the output in the file.csv). What can I do? Should I create a temporary table, order it and then store in the file?
                                  Tell me if the question is not clear.

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                                  0
                                  • VRoninV Offline
                                    VRoninV Offline
                                    VRonin
                                    wrote on last edited by VRonin
                                    #27

                                    Not a temporary table, you can use a QSortFilterProxyModel and then serialise the proxy rather than the original model.
                                    Since your current architecture relies on the QStandardItem interface rether than the QAbstractItemModel one you'll need to do some rewriting.

                                    To give you an idea, being QString m_csvSeparator the column separator:

                                    #include <QStringBuilder>
                                    QString escapedCSV(QString unexc) const
                                    {
                                        if (!unexc.contains(m_csvSeparator))
                                            return unexc;
                                        unexc.replace(QLatin1Char('\"'), QStringLiteral("\"\""));
                                        return '\"' % unexc % '\"';
                                    
                                    }
                                    bool writeCsv(QTextStream& writer, const QAbstractItemModel* constModel) const
                                    {
                                        if (!constModel)
                                            return false;
                                        for (int i = 0, maxRow = constModel->rowCount(); i < maxRow ; ++i) {
                                            for (int j = 0, maxCol = constModel->columnCount(); j < maxCol ; ++j) {
                                                const QString roleData = constModel->index(i, j).data().toString();
                                                if (j>0)
                                                    writer << m_csvSeparator;
                                                if (!roleData.isEmpty()) 
                                                    writer << escapedCSV(roleData);
                                            }
                                            writer << '\n';
                                        }
                                        return writer.status() == QTextStream::Ok;
                                    }
                                    

                                    "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                                    ~Napoleon Bonaparte

                                    On a crusade to banish setIndexWidget() from the holy land of Qt

                                    1 Reply Last reply
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