On Wed, 2011-07-27 at 19:17 +0200, Daniel Cámpora wrote:
> Hello again, Jeremy,
>
> I'm digging into this topic of the EventHandlers for the Widgets. Before
> implementing my own EventHandler for what I'm trying to do, I'm looking at
> how does MouseHandler works to see if I can use it.
>
> In an effort to track down what happens when the MouseHandler enters into
> action after a mouse action, I can see the responsibility is passed to the
> WindowManager. For instance, by looking at _handleMouseReleased:
>
>
> Code:
> bool WindowManager::_handleMouseReleased(float x, float y, bool& down) {
> down = false;
> if(!_lastPush) return false;
> Event ev(this, EVENT_MOUSE_RELEASE);
> setEventFromInterface(ev, _lastPush);
> bool handled = _lastPush->callMethodAndCallbacks(ev);
> _lastPush = 0;
> return handled;
> }
>
>
>
> An object of type EventInterface is in charge of executing
> callMethodAndCallbacks, which at last calls a virtual method mouseRelease,
> that can be overriden.
>
> I'm confused about the use of the term "callback" in the EventInterface. Is
> this a callback or an event triggered from the event handler? Or maybe it's
> used for both?
All are possible. You can either create a standalone callback object
totally independent of any Window or Widget, you can use a special
overridden method, or you can combine the two. This is what I meant when
I said earlier I tried to support too much at once. :) The method is
always called first, then all callbacks (until one returns true, at
which point they stop).
There are examples of both kinds of event handling in the source.
> I want to develop an EventHandler separate from the widget itself. Can I
> extend your code in some manner to achieve this, or should I go for a totally
> custom EventHandler?
>
> Thank you!
>
> Daniel
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=41671#41671
>
>
>
>
>
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