Timers in Abstract Gui API

Here is the basic idea of what I want to do:

Each widget, when part of the Gui has access to the event manager. The event manager is polymorphic so it contains functions from the underlying graphics / timer api. What I want to do is, allow Widgets to register timers, where they would call a function which would internally call the event manager to register the timer. Here is the problem, when a widget is first created, it is not part of the Gui. Therefore, no one could ever register timers in the widget constructor.

I thought of the fact that I could queue requests and when the widget becomes part of a gui, and can access the event manager, it can then dequeue the requests, but the problem with this is that it doesn't really allow me to do something like:

Timer *timer = registerTimer(0.17);

if(timer == NULL)
{
   //uh ohs
}
else
{
   tim开发者_如何学JAVAer->start();
}

Are there maybe better ways around my problem?

Thanks

Event management and providing timing facilities are 2 very different functionalities, so I would try to decouple event manager into 2 separate classes. Then you could make TimerManager a singleton and register timers from any places you like.

Alternatively if you cannot decouple event manager class as it is now, you can try to make it a singleton and access timing facilities this way.