QStateMachine animation with QFinalState, bug?

nen777w

I need to make a some geometry animation and catch the moment when we get to final state.

m_slide_mashine = new QStateMachine();
m_pSS = new QState();
m_pFS = new QState();
QFinalState *fs = new QFinalState();
m_slide_mashine->addState(m_pSS);
m_slide_mashine->addState(m_pFS);
m_slide_mashine->addState(fs);
m_pSS->addTransition(m_pFS);
m_pFS->addTransition(fs);

QPropertyAnimation *pAni = new QPropertyAnimation(panel->widget(), "geometry");
pAni->setEasingCurve(QEasingCurve::InOutCubic);
pAni->setDuration(DRAG_AND_DROP_CONSTANTS::library_panel_slide_speed);
m_slide_mashine->addDefaultAnimation(pAni);

connect(m_slide_mashine, &QStateMachine::finished, []() 
{
    //here we get to final state!
    int n = 0;
    n++;
});

Remark:
For m_pSS and m_pFS — I assigned the start and final geometry with a assignProperty() call.

Now the problem:
If I use the code above, the animation is not working :-(
But if I remove QFianl state from code i.e.:

m_slide_mashine = new QStateMachine();
m_pSS = new QState();
m_pFS = new QState();
m_slide_mashine->addState(m_pSS);
m_slide_mashine->addState(m_pFS);
m_pSS->addTransition(m_pFS);

QPropertyAnimation *pAni = new QPropertyAnimation(panel->widget(), "geometry");
pAni->setEasingCurve(QEasingCurve::InOutCubic);
pAni->setDuration(DRAG_AND_DROP_CONSTANTS::library_panel_slide_speed);
m_slide_mashine->addDefaultAnimation(pAni);

, animation work fine, but now I can't catch the moment when it finished.

SGaist

Hi,

There seems to be no condition at all to manage the transition to the final state. When should it go there ?

nen777w

Sorry I don't understand your question.
What "condition" you mean?

m_pSS - it's initial state (m_slide_mashine->setInitialState(m_pSS);)
then after assignProperty() I do m_slide_mashine->start();

SGaist

I mean that with that line for example: m_pSS->addTransition(m_pFS); as soon as your state machine enters the m_pSS state it will go to the m_pFSstate hence your animation not working as you expect. Thus my question, shouldn't you have a condition to transition from m_pSS to m_pFS ? For example a mouse click, number of animation repetition etc.

nen777w

Oh, understand! :-)
No condition is not required.
And sorry for my mistake in first post, when i said "animation is not working" I mean that after call m_slide_mashine->start() we immediately go from m_pSS -> m_pFS -> QFinalState (i.e. without duration) , but when I do not use QFinalState animation work as expected (with duration as I set in pAni->setDuration() ).

SGaist

It happens precisely because you didn't put any condition for the transition between the two states. If you take a look at the Simple State Machine example, the condition to change state is a mouse click.

So you have to determine what should trigger the transition between m_pSS and m_pFS and use the adequate QAbstractTransition subclass.

nen777w

Sorry but I don't understand again.
Why I need "condition" when API allow do that without it?
And why animation is broken only when I try to use QFinalState?

SGaist

The animation is not broken.

Like I already wrote: m_pSS->addTransition(m_pFS); means that as soon as your state machine enters the m_pSS state it will transition to m_pFSthus the state machine will stop since it's a final state.

nen777w

I understand.
Thank you!

SGaist

You're welcome !

So you could make it work the way you wanted ?

nen777w

Yes. Thank you!

SGaist

Great !

You'r welcome !

Since you have it working now, please mark the thread as solved using the "Topic Tools" button so that other forum users may know a solution has been found :)