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Save object to a file

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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #24

    You have to use a picture hosting service or a public dropbox folder etc...

    Interested in AI ? www.idiap.ch
    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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    • D Offline
      D Offline
      Dmon
      wrote on last edited by
      #25

      https://www.dropbox.com/s/oal5r9sjtsmy42l/Qt stack.jpg

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      • D Offline
        D Offline
        Dmon
        wrote on last edited by
        #26

        https://www.dropbox.com/s/mosnz8o23elipn5/Qtstack.jpg

        doesn't work with a space in the name

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #27

          Looks strange... Just to be on the safe side, delete the build directory completely and re-run your application.

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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          • D Offline
            D Offline
            Dmon
            wrote on last edited by
            #28

            ok now it doesn't run again with a bunch of errors:

            Running build steps for project Ass1Q1...
            Configuration unchanged, skipping qmake step.
            Starting: "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" -w
            mingw32-make: Entering directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop' C:/Qt/2010.04/mingw/bin/mingw32-make -f Makefile.Debug mingw32-make[1]: Entering directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
            g++ -c -g -frtti -fexceptions -mthreads -Wall -DUNICODE -DQT_LARGEFILE_SUPPORT -DQT_DLL -DQT_GUI_LIB -DQT_CORE_LIB -DQT_THREAD_SUPPORT -DQT_NEEDS_QMAIN -I"........\Qt\2010.04\qt\include\QtCore" -I"........\Qt\2010.04\qt\include\QtGui" -I"........\Qt\2010.04\qt\include" -I"........\Qt\2010.04\qt\include\ActiveQt" -I"debug" -I"." -I"..\Ass1Q1" -I"." -I"........\Qt\2010.04\qt\mkspecs\win32-g++" -o debug\FilmWriter.o ..\Ass1Q1\FilmWriter.cpp
            ..\Ass1Q1\FilmWriter.cpp: In member function 'void FilmWriter::saveFilm(Film&)':
            ..\Ass1Q1\FilmWriter.cpp:10: error: no matching function for call to 'QFileDialog::getSaveFileName(FilmWriter* const, const char [10])'
            ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qfiledialog.h:216: note: candidates are: static QString QFileDialog::getSaveFileName(QWidget*, const QString&, const QString&, const QString&, QString*, QFlagsQFileDialog::Option)
            ..\Ass1Q1\FilmWriter.cpp:14: error: no matching function for call to 'QMessageBox::critical(FilmWriter* const, const char [6], const char [20])'
            ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qmessagebox.h:202: note: candidates are: static QMessageBox::StandardButton QMessageBox::critical(QWidget*, const QString&, const QString&, QFlagsQMessageBox::StandardButton, QMessageBox::StandardButton)
            ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qmessagebox.h:262: note: static int QMessageBox::critical(QWidget*, const QString&, const QString&, int, int, int)
            ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qmessagebox.h:265: note: static int QMessageBox::critical(QWidget*, const QString&, const QString&, const QString&, const QString&, const QString&, int, int)
            ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qmessagebox.h:272: note: static int QMessageBox::critical(QWidget*, const QString&, const QString&, QMessageBox::StandardButton, QMessageBox::StandardButton)
            mingw32-make[1]: Leaving directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop' mingw32-make: Leaving directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
            mingw32-make[1]: *** [debug/FilmWriter.o] Error 1
            mingw32-make: *** [debug] Error 2
            The process "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" exited with code %2.
            Error while building project Ass1Q1 (target: Desktop)
            When executing build step 'Make'

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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #29

              FilmWriter is not a QWidget, you can't pass it as a parent when you call QFileDialog::getSaveFileName

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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              • D Offline
                D Offline
                Dmon
                wrote on last edited by
                #30

                If I make FilmWriter a QWidget the program runs but when I click on the save film button it crashes with: "this application has requested the runtime to terminate it in an unusual way. Please contact the application's support team for more information."

                Despite the crash, the program runs without any errors as you can see:
                Running build steps for project Ass1Q1...
                Configuration unchanged, skipping qmake step.
                Starting: "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" -w
                mingw32-make: Entering directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop' C:/Qt/2010.04/mingw/bin/mingw32-make -f Makefile.Debug mingw32-make[1]: Entering directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
                mingw32-make[1]: Nothing to be done for first'. mingw32-make[1]: Leaving directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
                mingw32-make: Leaving directory `C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
                The process "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" exited normally.

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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #31

                  Because you don't initialize it properly.

                  Don't make FilmWriter inherit QWidget and don't make it a parent of the QFileDialog, it doesn't make any sense.

                  For your tests just call QFileDialog::getSaveFileName().

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                  • D Offline
                    D Offline
                    Dmon
                    wrote on last edited by
                    #32

                    ok now I'm confused!?! I am calling getSaveFileNAme

                    void FilmWriter::saveFilm(Film& f){
                    QString fileName = QFileDialog::getSaveFileName(this,("Save File"));
                    if (fileName != "") {
                    QFile file(fileName);
                    if (!file.open(QIODevice::WriteOnly)) {
                    QMessageBox::critical(this, ("Error"),("Could not open file"));// error message
                    } else {
                    QTextStream stream(&file);
                    stream << f.toString();
                    stream.flush();
                    file.close();
                    }
                    }

                    }

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                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #33

                      change "this" by 0,

                      FilmWriter is not a QWidget and should not be just for the purpose of giving QFileDialog::getSaveFileName a parent.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                      • D Offline
                        D Offline
                        Dmon
                        wrote on last edited by
                        #34

                        ca you give me the line QString fileName = QFileDialog::getSaveFileName();
                        because I don't know what's wrong here?

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                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #35

                          Just call

                          @
                          QString fileName = QFileDialog()::getSaveFileName(0, tr("Save File..."));
                          @

                          Please, check the documentation

                          Interested in AI ? www.idiap.ch
                          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                          • D Offline
                            D Offline
                            Dmon
                            wrote on last edited by
                            #36

                            thank you very much I did try that but it also didn't work...Needed to change the 'this' for the QMessageBox also. Can I just ask why would pointing to this(itself) be the wrong thing to do?

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                            • SGaistS Offline
                              SGaistS Offline
                              SGaist
                              Lifetime Qt Champion
                              wrote on last edited by
                              #37

                              Because FilmWriter is not a widget.

                              And while you where inheriting QWidget, you never initialized it properly

                              Interested in AI ? www.idiap.ch
                              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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