CODEWITHSUNDEEP
c++qttimerqtimer
gloomikon
gloomikon

Reputation: 19

Use QTimer outside QObject

So, I've written my own class Personages. It has a function kill(), that makes Personage to be "dead". 

void Personages::kill()
{
    this->alive = false;
}

What I want to do is after it has been killed, call a timer to make Personage alive again in 1 second. To call a function like this: 

void Personages::reincarnate()
{
    this->alive = true;
}

I make this project in Qt and I've tried to use a QTimer, but, as I understood, it can be used only with QObject (my class isn't QObject). So my question is how can I achieve this?

 void Personages::kill()
    {
        this->alive = false;
        ????
    }

Okey, I've tried just to make it to be Q_OBJECT. class Personages is child-class of other class:

class Personages : public Objects

So, in Objects.h I've done the following:

class Objects: public QObject
{
    Q_OBJECT
...
}

Now Personages is Q_OBJECT too, am I right? Personages has these functions (.h):

    void            kill();
private slots:
    void            reincarnate();

And here is the code:

void Personages::kill()
{
    this->alive = false;
    this->timer = new QTimer(this);
    connect(this->timer, SIGNAL(timeout()), this, SLOT(reincarnate()));
    this->timer->start(1000);
}

void Personages::reincarnate()
{
    this->alive = true;
    this->timer->stop();
    delete this->timer;
}

It compiles but still the dead personage doesn't become alive. What is the problem? I have this error: QObject::connect: No such slot Objects::reincarnate() in ..\AndenturesOfLolo\personages.cpp:1074

Okey, I don't need to do any class to be a Q_OBJECT. Ali's answer worked exactly as I wanted

void Personages::kill()
{
    this->alive = false;
    QTimer::singleShot(5000, [=]() { reincarnate(); });
}

void Personages::reincarnate()
{
    this->alive = true;
}

Upvotes: 0

Views: 1516

Answers (2)

user10737101
user10737101

Reputation:

Now Personages is Q_OBJECT too, am I right?

No, Personages does not inherit Q_OBJECT from Objects but needs to be Q_OBJECT as well for the slot reincarnate to be recognized. Making the super class of Personages a Q_OBJECT does not make Personages a Q_OBJECT class - if it did then you would never have to declare a QObject-derived class as Q_OBJECT, and similarly you would never be able to make a QObject subclass that wasn't a Q_OBJECT class.

Try adding the Q_OBJECT line to your definition for Personages and see if that works.

Upvotes: 0

Ali Tavakol
Ali Tavakol

Reputation: 439

Does this help?

QTimer::singleShot(2000, [=]() { foo(); });

Upvotes: 1

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