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    Qt World Summit: Early-Bird Tickets

    Solved Problem with saving function (overwrite file which saved by dialog)

    General and Desktop
    save qtextedit file function
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    • ?
      A Former User last edited by

      Hi.

      I have a save function, which open a Dialog for selecting Directory.

      QString fileName = QFileDialog::getSaveFileName(this, tr("Speichern unter..."),
                                                         QString("Unbenannt.htm"), tr("TextPad 1.0 (*.htm);;"));
         QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation);
      
         QFile file(fileName, this);
      
         if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
         {
            qDebug() << "Fehler beim Speichern der Datei";
         }
      
         QTextStream out(&file);
         out << toHtml();
         file.close();
      

      This works fine. But when i saved a file first time by the Dialog i don't want to open the Dialog for saving every changes in the document...

          QFile file;
          QString path = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation) + '/' + "UnsavedFile.htm";
          file.setFileName(path);
      
      
         if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
            return;
      
         QTextStream out(&file);
         out << toHtml();
         file.close();
      

      This is the function for saving the changes in the file i saved before with the Dialog.

      I don't know why. Thanks
      Henrik

      1 Reply Last reply Reply Quote 0
      • ?
        A Former User last edited by

        Hi! I didn't get it. Could you please elaborate a bit more on what it is you want to achieve and what doesn't work so far?

        ? 1 Reply Last reply Reply Quote 0
        • ?
          A Former User @Guest last edited by

          @Wieland
          Hi!
          The function wth opening the Dialog is the saveUnder function like in word.
          The function whthout opening Dialog is the save function like in word. And this function (second quellcode example) doesn't work...

          I hope you understand now

          1 Reply Last reply Reply Quote 0
          • ?
            A Former User last edited by

            Hmm... works for me. Maybe you're looking for your file in the wrong directory? In your first code snippet you use QStandardPaths::GenericDataLocation and in the second you use QStandardPaths::DocumentsLocation. Also, in the first snippet your (German) filename is Unbenannt.htm and in the second snippet it's (English) UnsavedFile.htm.

            ? 1 Reply Last reply Reply Quote 0
            • ?
              A Former User @Guest last edited by

              @Wieland

                  QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation);
              
                  QFile file;
                  file.setFileName(fileName);
              
                  if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
                  {
                     qDebug() << "Fehler beim Speichern der Datei";
                  }
              
                  QTextStream out(&file);
                  out << toHtml();
                  file.close();
              

              This is my saveFunction without Dialog. This doesn't work. SaveUnder Function is same as i post earlier

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              • ?
                A Former User last edited by A Former User

                Okay, so this is your function:

                void MainWindow::mySaveFunction() const
                {
                    QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation);
                
                    QFile file;
                    file.setFileName(fileName);
                
                    if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
                    {
                        qDebug() << "Fehler beim Speichern der Datei";
                    }
                
                    QTextStream out(&file);
                    out << toHtml();
                    file.close();
                }
                

                I guessed it's a member function of something, let's assume this something is MainWindow. Next guess is toHtml is another member function. So, the following line does nothing:

                QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation);
                

                And what about fileName? Is that a member variable?

                ? 2 Replies Last reply Reply Quote 1
                • ?
                  A Former User @Guest last edited by

                  @Wieland
                  toHtml() is QString
                  fileName is QString

                  And yes, the function is of QMainWindow

                  1 Reply Last reply Reply Quote 0
                  • ?
                    A Former User @Guest last edited by

                    @Wieland
                    void MainWindow::mySaveFunction()

                    without const

                    1 Reply Last reply Reply Quote 0
                    • ?
                      A Former User last edited by

                      Maybe your fileName is wrong? Try this:

                      if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
                      {
                        qDebug() << QString("Fehler beim Speichern der Datei: %1").arg(fileName);
                      }
                      
                      ? 1 Reply Last reply Reply Quote 0
                      • ?
                        A Former User @Guest last edited by

                        @Wieland

                        QFSFileEngine::open: No file name specified
                        "Fehler beim Speichern der Datei: "
                        QIODevice::write (QFile, ""): device not open
                        
                        ? 1 Reply Last reply Reply Quote 0
                        • ?
                          A Former User @Guest last edited by

                          @HenrikSt. Congrats, you just found your problem, fileName is empty :-)

                          1 Reply Last reply Reply Quote 0
                          • ?
                            A Former User last edited by

                            That good, i know..

                            But i don't know how to fix.
                            If you help me I am very happy :-)

                            ? 1 Reply Last reply Reply Quote 0
                            • ?
                              A Former User @Guest last edited by

                              You must assign some useful value to fileName, e.g. like this:

                              void MainWindow::mySaveFunction()
                              {
                                  const QString path = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
                                  QFile file;
                                  fileName = QString("%1/%2").arg(path).arg("unbenannt.html");
                                  file.setFileName(fileName);
                              
                                  if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
                                  {
                                      qDebug() << QString("Fehler beim Speichern der Datei: %1").arg(fileName);
                                  }
                              
                                  QTextStream out(&file);
                                  out << toHtml();
                                  file.close();
                              }
                              
                              ? 1 Reply Last reply Reply Quote 1
                              • ?
                                A Former User @Guest last edited by

                                @Wieland
                                Hi, this works, but the Problem is, that you create a new file ("unbenannt.html")

                                I want to overwrite the file i create with the Dialog before. You understand?

                                ? 1 Reply Last reply Reply Quote 0
                                • ?
                                  A Former User @Guest last edited by

                                  @HenrikSt. In this case the name you assign to fileName here must exactly match the name of the existing file.

                                  ? 1 Reply Last reply Reply Quote 0
                                  • ?
                                    A Former User @Guest last edited by

                                    @Wieland
                                    I know... But every user enter another fileName so "unbenannt.htm" will not work..

                                    Do you have another idea?

                                    Thanks :)

                                    ? 1 Reply Last reply Reply Quote 0
                                    • ?
                                      A Former User @Guest last edited by

                                      @HenrikSt. After the user entered the file name the first time, just save the name then and use it again later.

                                      ? 1 Reply Last reply Reply Quote 0
                                      • ?
                                        A Former User @Guest last edited by

                                        @Wieland
                                        Ah ok. I'm new in Qt. Can you write an example for this case that i can use it?

                                        I have Problems with writing Code. Reading is no Problem. Do you have any tips for me?

                                        ? 1 Reply Last reply Reply Quote 0
                                        • ?
                                          A Former User @Guest last edited by

                                          The following code isn't very elegant but I think it's good enough to serve as an example.

                                          mainwindow.h

                                          #ifndef MAINWINDOW_H
                                          #define MAINWINDOW_H
                                          
                                          #include <QMainWindow>
                                          
                                          namespace Ui {
                                          class MainWindow;
                                          }
                                          
                                          class MainWindow : public QMainWindow
                                          {
                                              Q_OBJECT
                                          
                                          public:
                                              explicit MainWindow(QWidget *parent = 0);
                                              ~MainWindow();
                                              bool mySaveFunction();
                                              QString toHtml() const;
                                          
                                          private slots:
                                              void saveFile();
                                          
                                          private:
                                              Ui::MainWindow *ui;
                                              QString m_fileName;
                                          
                                          };
                                          
                                          #endif // MAINWINDOW_H
                                          

                                          mainwindow.cpp

                                          #include "mainwindow.h"
                                          #include "ui_mainwindow.h"
                                          
                                          #include <QFile>
                                          #include <QTextStream>
                                          #include <QDebug>
                                          #include <QStandardPaths>
                                          #include <QFileDialog>
                                          #include <QMessageBox>
                                          
                                          bool MainWindow::mySaveFunction()
                                          {
                                              // if this happens we have a bug in our code
                                              Q_ASSERT_X(!m_fileName.isEmpty(), "mySaveFunction", "m_fileName is empty");
                                          
                                              QFile file(m_fileName);
                                              if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
                                              {
                                                  QMessageBox::critical(this, "Fehler", QString("Fehler beim Speichern der Datei: %1").arg(m_fileName) );
                                                  return false;
                                              }
                                              QTextStream out(&file);
                                              out << toHtml();
                                              file.close();
                                              QMessageBox::information(this, "Information", QString("Die Datei wurde gespeichert: %1").arg(m_fileName) );
                                              return true;
                                          }
                                          
                                          
                                          MainWindow::MainWindow(QWidget *parent) :
                                              QMainWindow(parent),
                                              ui(new Ui::MainWindow)
                                          {
                                              ui->setupUi(this);
                                              connect(ui->pushButton, SIGNAL(clicked(bool)), this, SLOT(saveFile()));
                                          }
                                          
                                          MainWindow::~MainWindow()
                                          {
                                              delete ui;
                                          }
                                          
                                          QString MainWindow::toHtml() const
                                          {
                                              return "<html></html>\n";
                                          }
                                          
                                          void MainWindow::saveFile()
                                          {
                                              if (m_fileName.isEmpty()) {
                                                  // first attempt to save the file
                                                  m_fileName = QFileDialog::getSaveFileName(this, tr("Speichern unter..."),
                                                                                  QString("Unbenannt.htm"), tr("TextPad 1.0 (*.htm);;"));
                                                  if (m_fileName.isEmpty()) {
                                                      return; // dialog was canceled
                                                  }
                                              }
                                              if (!mySaveFunction()) {
                                                  m_fileName.clear(); // saving failed. clear m_fileName so the QFileDialog will come up again next time
                                              }
                                          }
                                          
                                          ? 1 Reply Last reply Reply Quote 1
                                          • ?
                                            A Former User @Guest last edited by

                                            @Wieland
                                            Hi, thank you for the example

                                            if (!mySaveFunction()) {
                                                    m_fileName.clear(); // saving failed. clear m_fileName so the QFileDialog will come up again next time
                                                }
                                            
                                            

                                            This Code is not working...

                                            C:\Users\Henrik\Documents\TextPad\pagestextedit.cpp:557: Fehler: could not convert 'PagesTextEdit::saveUnderDocument()' from 'void' to 'bool'
                                                         if (!saveUnderDocument()) {
                                                                                ^
                                            

                                            I have void MainWindow::save....
                                            and not bool

                                            How can i Change it?

                                            One Problem is existing..
                                            When i open a file e.g. from Desktop and i write something in and want to save it with mySaveFunction i get an runtime error...
                                            Do you know why?

                                            Thanks a lot

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