QTimer to execute method every second - c++

Question

I'm learning Qt and I was reading about Threads, Events and QObjects from Qt wiki, and followed the wiki recommendations on how to handle some work in a while condition but its not working for my specific case. Here's a simple example of what I'm currently trying to achieve.
class FooEvents : public FooWrapper {
public virtual serverTime(..) { std::cout << "Server time event\n"; }
public virtual connected(..) { std::cout << "Connected event\n"; }
}
class Foo : public QObject {
private:
FooAPI *client;
public:
Foo(FooEvents *ev, QObject *parent = 0) : client(new FooApi(ev)) { .. }
private slots:
void processMessages() {
if (state is IDLE)
reqFooAPiServerTime();
select(client->fd()+1, ...);
if (socket is ready for read)
client.onReceive();
}
public:
void connect(...) {
if (connection) {
QObject::connect(&timer, SIGNAL(timeout()), this, SLOT(processMessages()));
timer.start(1000); // I don't get the output from FooEvents
}
}
}
This is a very simple but I think it illustrates my case. Why is this not working and what other alternatives to I have to handle this case? Thanks.s
Edit: The processMessages is being called every second but I don't get any output from the events

Answer 1

Where is timer declared and defined?
If it's local to Foo::connect() it'll be destroyed before it ever has a chance to fire. Presumably it just needs to be a member object of the Foo class.
Also keep in mind that QObject provides it's own simple interface to a timer - just override the protected virtual timerEvent() function and call QObject's startTimer() to start getting those timer events. In this case instead of having a slot to receive the timer events, they will just end up at the overridden timerEvent() function:
protected:
void timerEvent(QTimerEvent *event) {
processMessages();
}
public:
void connect( /* ... */ ) {
// ...
startTimer(1000);
}

Answer 2

This won't work, because processMessages() is not a SLOT.
So Declare processMessages() as a private slot and then try.

Answer 3

You don't declare the timer neither the slot. In the header you must declare:
class ... {
QTimer timer;
...
private slots:
void processMessages();
...
};
Then remember to make the SIGNAL-SLOT connection and configure the timer:
connect(&timer, SIGNAL(timeout()), this, SLOT(processMessages()));
timer.setInterval(1000);
timer.start();
Also timer.start(1000); would be valid...
ANOTHER POSSIBILITY
Other possibility would be to use the timer associated with each Q_OBJECT and overload the timerEvent:
class ... {
Q_OBJECT
...
protected:
void timerEvent(QTimerEvent *event);
...
};
Then you must implement the timer event as this:
void MyClass::timerEvent(QTimerEvent *event) {
processMessages();
}
And you can configure the timer with a simple call to startTimer(1000);