Save object to a file

SGaist

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

Dmon

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'

SGaist

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

Dmon

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.

SGaist

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().

Dmon

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();
}
}

}

SGaist

change "this" by 0,

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

Dmon

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

SGaist

Just call

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

Please, check the documentation

Dmon

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?

SGaist

Because FilmWriter is not a widget.

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