QCommandLineParser to select gui or non-gui mode

[mcosta]

Hi,

in my project we use this techinque

QSharedPointer<QCoreApplication> app;
if(commandLine) {
    app.reset(new QCoreApplication(argc, argv));
} else {
    app.reset(new QApplication(argc, argv));
}

where commandLine is initialized parsing the command line arguments

[A Former User]

You could also copy the contents of argv[] into a QStringList and then use QCommandLineParser before you create any Q*Application with:
void QCommandLineParser::​process(const QStringList & arguments)

[mcosta]

@Wieland said:

You could also copy the contents of argv[] into a QStringList and then use QCommandLineParser before you create any Q*Application with:
void QCommandLineParser::​process(const QStringList & arguments)

We use QCommandLineParser to parse the arguments

[shavera]

@Wieland
This works... to a degree. 1, it still feels kludgey to construct a stringlist of arguments to parse.
Second, I can't add in help or version options in this way. I have to instantiate the application to get these, I think?

[A Former User]

@mcosta
I think @shavera's biggest concern is, like she said:

If I want to use QCommandLineParser, I must first create an application object.

Her assumption is wrong as there isn't only void QCommandLineParser::​process(const QCoreApplication & app) but also void QCommandLineParser::​process(const QStringList & arguments).

@shavera said

This works... to a degree. 1, it still feels kludgey to construct a stringlist of arguments to parse.
Second, I can't add in help or version options in this way. I have to instantiate the application to get these, I think?

This is all true. Maybe you should file a bug and request some improvement of QCommandLineParser. But honestly I don't think this would be implemented in the near future.

[shavera]

@mcosta I don't precisely understand what you mean in either comment. Using QCommandLineParser seems to either require a Q*Application already created, or to pass in a self-generated list of arguments to the parser, which one could then use to decide which type of application to generate. (but at the loss of some other functionality of QCommandLineParser, it seems to me)

[shavera]

@Wieland

Yeah I was initially thinking along the lines of a bug report/suggested feature, but I wanted to make sure I wasn't overlooking some obvious solution. For instance, my initial attempt, I just used QCoreApplication::arguments() to generate the stringlist, forgetting that isn't a static function, which generated an error.

[A Former User]

@shavera Looks like there is no nice solution by now. I've actually seen multiple people complaining about this. :-(

[mcosta]

Hi,

the complete code is this

    CommandFactory factory;
    bool foundParams = factory.commandLineParamsArePresent(argc, argv, error);
    
    QSharedPointer<QCoreApplication> app;
    if(foundParams) {
        if(!error.isEmpty()) {
            qDebug() << error;
            return 1;
        }
        app = QSharedPointer<QCoreApplication>(new QCoreApplication(argc, argv));
    } else {
        app = QSharedPointer<QCoreApplication>(new CWinAdminApp(argc, argv));
    }

The CommandLineFactory::commandLineParamsArePresent() use a QCommandLineParser to parse the argv[] contents before creating any Q*Application instance.

[shavera]

@mcosta I can see how that could work, but it runs into the initial kludge problem, that you have to parse for whether a command line option is present (or more specifically, that a specific command line option is present in the case of multiple options), which you then use to construct the application (and potentially pass this application object through the CommandLineOption stuff itself)

[mcosta]

@shavera I understand what do you mean but honestly I don't think such kind of feature could be useful; you need anyway to do something manually to run in GUI or non-GUI mode.