Lifecycle method called when binding the object.
Important : Make sure you call your parent class
#onBind(). Also, do
not call directly, call
#bind() instead.
Any event handler should be
initialised here rather than in the constructor. Also, it is good practice to
perform any costly initialisation here.
Handlers registered by calling
#registerHandler(HandlerRegistration) will be removed
when unbinding. Any other initialisation that takes place here (or as a
side-effect of what is done here) should be taken down in
#onUnbind().
This method will never be invoked more then once, or if it is, the second
time will necessarily be preceded by an invocation of
#onUnbind().