Problems writing to file

[DiamonDogX]

I have a logging class that I wish to use to append messages to a file. Naturally, I wrote a write(QString msg) for my class that I wish clients to be able to call in order to append a message to the current log file. But I can't seem to successfully write to the file... it seems to have a problem with how I am using my member variables. I have successfully written to a file like this, but only when I open it and write to it in one block of code (like how you see here: http://www.digitalfanatics.org/proje...chapter08.html). Here's my code that isn't working (_fileTextStream is a member variable of type QTextStream):

Logger::Logger()
{
	QFile file( "log.txt" );
	if ( !file.open( QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text ) ) 
	{
        QMessageBox::critical( NULL,
                               tr("Error opening log file for writing."),
                               tr("Couldn't open file: %1").arg( file.errorString() ) );
    }
 
	QTextStream _fileTextStream( &file );
}
 
 
void Logger::write( QString message )
{
	_fileTextStream << message << endl;
}

Logger::Logger()
{
	QFile file( "log.txt" );
	if ( !file.open( QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text ) ) 
	{
        QMessageBox::critical( NULL,
                               tr("Error opening log file for writing."),
                               tr("Couldn't open file: %1").arg( file.errorString() ) );
    }
	
	QTextStream _fileTextStream( &file );
}


void Logger::write( QString message )
{
	_fileTextStream << message << endl;
}

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[Lykurg]

Logger::Logger()
{
	QFile file( "log.txt" );
	if ( !file.open( QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text ) ) 
	{
        QMessageBox::critical( NULL,
                               tr("Error opening log file for writing."),
                               tr("Couldn't open file: %1").arg( file.errorString() ) );
    }
 
	QTextStream _fileTextStream( &file );
}
 
 
void Logger::write( QString message )
{
	_fileTextStream << message << endl;
}

Logger::Logger()
{
	QFile file( "log.txt" );
	if ( !file.open( QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text ) ) 
	{
        QMessageBox::critical( NULL,
                               tr("Error opening log file for writing."),
                               tr("Couldn't open file: %1").arg( file.errorString() ) );
    }
	
	QTextStream _fileTextStream( &file );
}


void Logger::write( QString message )
{
	_fileTextStream << message << endl;
}

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In that code _fileTextStream is only a local variable and therefore your code is not working. Make _fileTextStream a real member variable and use QTextStream::setDevice().

Edit:

class Logger
{
  //....
  private:
    QTextStream _fileTextStream;
}
 
Logger::Logger()
{
  //..
  _fileTextStream.setDevice(&file);
}

class Logger
{
  //....
  private:
    QTextStream _fileTextStream;
}

Logger::Logger()
{
  //..
  _fileTextStream.setDevice(&file);
}

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[DiamonDogX]

That did not seem to fix the problem... the file is still not written to.

[mcosta]

The problem is QFile is destroyed when constructor terminate.
QFile automatically close the file controlled when the object is destroyed