How to create command line arguments
-
I'm trying to make a relatively simple program for Linux, and I need to have one possible command line argument. Let's say the executable name/command is program, I want to be able to launch it with a command line parameter, m. So program -m and i will have it start with a second window open which will be closed by default if no command line parameter/argument was passed.
How do I make the program look for and understand command line arguments?
-
Hi,
One possibility is "QCommandLineParser":http://doc.qt.io/qt-5/qcommandlineparser.html
Hope it helps
-
Yes that looks like exactly what I was looking for, but I can't seem to figure out how to use it.
I added private: bool showMR; in mainwindow.h, then in main.cpp (main class)
@ QApplication a(argc, argv);
QCommandLineParser parser;
QCommandLineOption showMROption("m", QCoreApplication::translate("main", "Shows the MR Buffer file on startup."));
parser.addOption(showMROption);
bool showMR = parser.isSet(showMROption);@and finally in mainwindow.cpp
@ if (showMR)
ui->MR_Buffer->setText("MR SHOW");@i went to run options and added to the argument line m (I also tried -m) but the test case I put in the if(showMR) never occurs ("MR SHOW" is not printed to MR_Buffer) where did I go wrong?
-
Didn't you forgot
@
// Process the actual command line arguments given by the user
parser.process(app);
@?
-
Yes I indeed did forget that one. I added it in but my results did not change.
I think it has to do with my bool showMR. If I change my line in main.cpp from
@bool showMR = parser.isSet(showMROption);@
to
@showMR = parser.isSet(showMROption);@
it tells me Use of undeclared identifier 'showMR' (which means main.cpp, or at least the main class in it is unable to read/write the showMR bool from mainwindow.h, whereas mainwindow.cpp reads it just fine; but reads it as false since main.cpp doesn't seem to be able to interact with it. (And yes mainwindow.h is included in the main.cpp file)
How do I pass the variable/argument/bool from main.cpp to mainwindow.cpp?
-
Add a setter to your MainWindow class where you update the value of showMR and proceed with the update of your UI
-
"Here":http://stackoverflow.com/questions/15383167/how-to-write-setter-for-class-member-variable you have an example
-
I'm still running into problems with setting showMR... under public in mainwindow.h MainWindow class:
@ bool showMR;
bool m_showMR;
void setshowMR(bool showMR){m_showMR = showMR;}@in main.cpp
@ MainWindow::showMR = parser.isSet(showMROption);@
Debugger:
@main.cpp:11: error: invalid use of non-static data member 'showMR'
MainWindow::showMR = true;
~~~~~~~~^ -
showMR and m_showMR are not a static variables (nor should they be)
@
MainWindow mw;
mw.setShowMR(parser.isSet(showMROption));
@ -
Allright, I saw some progress. (As in it actually compiled this time and ran through my if/switch)
mainwindow.h
@public:
bool showMR;
bool m_showMR;
void setshowMR(bool showMR) {m_showMR = showMR;}private:
bool getshowMR() {return m_showMR;}@main.cpp (main class)
@ QApplication a(argc, argv);
QCommandLineParser parser;
QCommandLineOption showMROption("m", QCoreApplication::translate("main", "Shows the MR Buffer file on startup."));
parser.addOption(showMROption);
parser.process(a);
MainWindow w;
w.setshowMR(parser.isSet(showMROption));
w.show();return a.exec();@mainwindow.cpp
@ ui->setupUi(this);
loadFiles();
switch (getshowMR()){
case true:
ui->MR_Buffer->setText("MR SHOW");
break;
case false:
ui->MR_Buffer->setText("MR HIDE");
break;@Right now the switch is always returning "false". If I do what (i think) you said
main.cpp
@ QApplication a(argc, argv);
QCommandLineParser parser;
QCommandLineOption showMROption("m", QCoreApplication::translate("main", "Shows the MR Buffer file on startup."));
parser.addOption(showMROption);
MainWindow mw;
parser.process(a);
mw.setshowMR(parser.isSet(showMROption));
MainWindow w;
w.show();return a.exec();@The switch always returns "true" (I checked if it made any difference to add the "m" or "-m" or remove the argument in the project settings, it had no effect) but at least it's compiling by now.
What seems to be happening is that if I initialize two instances of the MainWindow class, the getter will return True, if I initialize only one instance the getter will return False, which is completely beyond my understanding, and of course is completely ignoring my command line arguments.
