Using QApplication with command line arguments

Question

QApplication::QApplication ( int & argc, char ** argv )

Initializes the window system and constructs an application object

Answer 1

The arguments passed in the constructor are later accessible through the static method
QStringList QCoreApplication::arguments(). By this, command line arguments can be handled everywhere in your code.

Answer 2

Continue reading that documentation. The set of flags QApplication acts on is listed there.

Try for example:

./qt -style=windows

The arguments that QApplication doesn't deal with are simply left alone. The ones it does process are removed (which is why that function takes non-const arguments).

Answer 3

The suggestion about using QCoreApplication is only recommended of you have a console application. If you are using a QApplication instead, and want to access command-line arguments from inside a QWidget, you can do it with the global pointer qApp:

Here you can find the documentation from Nokia, or here from qt-project.org . In the documentation browser of Qt Creator I couldn't find it, so it is at best not that easily accessible.

so you can find:

int my_argc = qApp->arguments().count();

QString my_argv_0 = qApp->arguments.at(0);

...

and so on.

I know this question is old, but took me some time to find a way to do it from within my Main Window, so hope this helps someone else.