Run slots in order with function in between

Tiago M.Pinto

Hi!

I am trying to emit a signal (which should trigger its slot immediately) at the beginning of a function, then I wait for another function to return and then I emit another signal whose slot should be the last thing to run. Here is the example:

void mainFun(void)
{
   emit signal1();

   subFun();

   emit signal2();
}

I already tried different types of connections (Qt::DirectConnection and Qt::QueuedConnection) but both slots seem to run at the end of mainFun() after subFun() has returned.

Is there any way I could solve this?

Thanks!

jsulm

@Tiago-M-Pinto said in Run slots in order with function in between:

is not providing it, but I didn't figure out yet how to enable/disable buttons using state machines

You can use lambdas:

QObject::connect(state1, &QState::entered, [this](){ button2->setEnabled(false); });

SGaist

Hi,

Where exactly is that code run in your application ?

Tiago M.Pinto

Hi @SGaist,

This mainFun() is actually another slot from an object and it is called after a signal is emitted when I click in a button of that object. What I want is to disable some buttons when I click in that button, then run subFun() and finally enable the buttons again.

SGaist

Sounds like you should handle these things whith a small QStateMachine. On entering the state, disable what you want and on leaving the state change stuff back again.

Tiago M.Pinto

Thank you @SGaist

I tried to implement a simple machine consisting in switching two buttons on and off but it is not working. This is the code in my object's constructor:

m_machine = new QStateMachine(this);
QState *state1 = new QState();
QState *state2 = new QState();

state1->addTransition(button1,&QPushButton::clicked,state2);
state2->addTransition(button2,&QPushButton::clicked,state1);

QObject::connect(state1,&QState::entered,button2,&QPushtButton::setDisabled);
QObject::connect(state1,&QState::entered,button1,&QPushtButton::setEnabled);
QObject::connect(state2,&QState::entered,button2,&QPushtButton::setEnabled);
QObject::connect(state2,&QState::entered,button1,&QPushtButton::setDisabled);

m_machine->addState(state1);
m_machine->addState(state2);
m_machine->setInitialState(state1);
m_machine->start();

I know that the slot QPushtButton::setDisabled expects a boolean and the signal QState::entered is not providing it, but I didn't figure out yet how to enable/disable buttons using state machines. Is there another way?

jsulm

@Tiago-M-Pinto said in Run slots in order with function in between:

is not providing it, but I didn't figure out yet how to enable/disable buttons using state machines

You can use lambdas:

QObject::connect(state1, &QState::entered, [this](){ button2->setEnabled(false); });

Tiago M.Pinto

Hi @jsulm, thanks!

I didn't think of that. It works but I needed to capture my button2 to the lambda function instead of this pointer.
In the meanwhile I figured out how to solve this the other way. I found the signal &QState::activeChanged that emits the boolean as I wanted.

Thank you all. I will mark this topic as solved.

gracieanderson

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