I've read that thing about the signals/slots =
and that was exactly what I was trying to do (at least I thought that was e=
xactly what they said). Here's an example from a Qt Address Book tutorial:<=
br>
connect(nextButton, SIGNAL(clicked()), this, SLOT(next()));
=
As the QMessageBox needs a parent reference, 'this' is fine for the MainWin=
dow. This is my slot:
QObject.Connect(btnAbout, Qt.SIGNAL("clicked()=
"), mainwin, =0AQt.SLOT("ShowAbout(mainwin, page)"));
First, the Qt =
one doesn't have these " ", so I thought it might be a Qyoto thing. 'this' =
is a reference to MainWindow. In my StartWindow, 'mainwin' is a reference t=
o the MainWindow. If I use a slot in MainWindow I pass the slot a 'this' re=
ference as in the example. If I use a slot in the StartWindow I pass it a r=
eference to MainWindow as 'mainwin'.
Are you saying if I declare the=
SecondWindow class as inherited from :QWidget I should then pass the refer=
ence to itself as 'this' rather than a reference to the MainWindow?
=
In the StartWindow the QMessageBox also needs a parent reference, that's wh=
y I pass 'mainwin' - reference to parent MainWindow. What do you mean=
by passing a type rather than a variable? How do you pass a type if you ne=
ed to pass a reference to the parent window? If I pass anything else it com=
plains that that reference doesn't exist in the current context.
=0A
=
Yes. You didn't understan=
d how signals and slots work. This explains it all: http://doc.tro=
lltech.com/4.6/signalsandslots.html . Short summery: This line QObject.Connect(btnAbout, Qt.SIGNAL("clicked()"), mainwin,
Qt.SLOT("S=
howAbout(mainwin, page)"));
connects to a method (slot) ShowAbout() whic=
h takes two arguments: one of type
mainwin, one of type page. There are=
two reasons why this won't work:
1. The signal doesn't provide any =
parameters, but the slot does. How is this
supposed to work?
2. You =
give a method signature to the SLOT method, i.e. mainwin and page are
e=
xpected to be types, not variables. But there is no type called 'mainwin' a=
nd
there is also no type called 'page'. Both are variables. But this
is not how
signals and slots work. SIGNAL and SLOT expect _signatures_=
, not method call
expressions.
Furthermore, you can only define =
slots in QObject subclasses. Otherwise you
have to use delegate connect=
ions. (QObject.Connect(sender, SIGNAL(/*signal*/),
delegate { /* ... */=
});)
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