Removing transitions from a QState causes crash

alasdairhatfield

Hi,

I add two transitions to the state and build up a list of states thus:

@ Transitions.append(WelcomeState->addTransition(HelpSignalMapper, SIGNAL(mapped(QString)), HelpState));
Transitions.append(WelcomeState->addTransition(GuiSignalMapper, SIGNAL(mapped(QString)), BasicProdState));
@

This works and on running the code, the transitions occur.
Later I want to remove the states but all attempts cause the application to crash, not at the point I remove the transitions but a couple of lines later. (If I comment out the code removing the states then the rest of the application continues to run ok)

I have tried two methods to remove the transitions but the result is the same:

Either using the list I built up myself:

@ while (!Transitions.isEmpty()) {
WelcomeState->removeTransition(Transitions.takeFirst());
}@

Or using the transitions() method to gain the list of transitions:

@ QList<QAbstractTransition*> transitions = WelcomeState->transitions();
while (!transitions.isEmpty()) {
WelcomeState->removeTransition(transitions.takeFirst());
}@

Any ideas as I can't see what I am doing wrong.

Thanks

codenode

Have you tried to debug this code?
Is WelcomeState still a valid pointer?

alasdairhatfield

Have checked again just to be sure.
WelcomeState gets a value in the constructor

@
WelcomeState = new QState();
@

and this is the same when I reach

@
QList<QAbstractTransition*> transitions = WelcomeState->transitions();
@

niko

Hi,

I just checked that. For me, it works, when I do the remove-thing in the state you are reaching.

For example, when you have 3 transitions in state A and you go from state A to state B, you can remove the transitions from state A in state B.

Hope it helps.