Basic question about signal slot
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[quote author="Andre" date="1375445688"]Of course not: if you want slots, you need Q_OBJECT.
Re-insert Q_OBJECT, re-run qmake (as you were told to do by raven-worx), and re-compile.[/quote]
Yes but then I get the error that I mentioned in
"Link to the post...":http://qt-project.org/forums/viewthread/30800/#136159 -
Hi, you should connect SIGNAL to SLOT, but you are connecting a SLOT to SIGNAL now.
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[quote author="1+1=2" date="1375446251"]Hi, you should connect SIGNAL to SLOT, but you are connecting a SLOT to SIGNAL now.[/quote]
I have tried that as well. Now in my actual code it is running like:
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connect(this,SIGNAL(sgSetTheThreshold(float)), this, SLOT(SetTheThreshold(float)));
@I think it should work in both ways.
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[quote author="dolevo" date="1375446069"]
[quote author="Andre" date="1375445688"]Of course not: if you want slots, you need Q_OBJECT.Re-insert Q_OBJECT, re-run qmake (as you were told to do by raven-worx), and re-compile.[/quote]
Yes but then I get the error that I mentioned in
"Link to the post...":http://qt-project.org/forums/viewthread/30800/#136159[/quote]
Ah... your problem is that you are using multiple inheritance of QObject. You have the dreaded diamond-shaped inheritance diagram. Don't do that. It is not supported.[quote author="dolevo" date="1375446385"]
[quote author="1+1=2" date="1375446251"]Hi, you should connect SIGNAL to SLOT, but you are connecting a SLOT to SIGNAL now.[/quote]I have tried that as well. Now in my actual code it is running like:
@
connect(this,SIGNAL(sgSetTheThreshold(float)), this, SLOT(SetTheThreshold(float)));
@I think it should work in both ways.[/quote]
No, it will not work both ways. You can connect a signal to a slot, or to
another signal, or with Qt 5 even to a normal member function or a functor or a lambda function. But you cannot connect a slot to anything. -
No. The error you give us, suggests to me that you are using multiple inheritance, and that class B is already descendant from QObject. Your class currently inherits from QObject and B. If B also directly or indirectly inherits QObject, you have the diamond-shaped multiple inheritance, and QObject will not function properly if you do that. In your case, the solution is simple: only inherit from B.
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[quote author="raven-worx" date="1375444124"]let the highest class derive from QObject and rerun qmake.[/quote]
i think i was unclear with that post... thats what i meant with "highest" class. (hierarchical highest class, the most basic class, and only this one) .. sry -
[quote author="dolevo" date="1375446799"]I didn't get what I should not do?
[/quote]
As Andre said, you should not use multiple inheritance of QObject.The Qt documentation says that:
If you are using multiple inheritance, moc assumes that the first inherited class is a subclass of QObject. Also, be sure that only the first inherited class is a QObject.
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// correct
class SomeClass : public QObject, public OtherClass
{
...
};
@
