Python实现Event回调机制的方法

public delegate void NewToolGotEvent();

public class ToolBag
{
 event NewToolGotEvent newToolGotHandler;

 void Start()
 {
  newToolGotHandler += renderRedPoint;
  newToolGotHandler += renderNewTool;
  newToolGotHandler += renderAvaliableUseBtn;
 }

 void renderRedPoint()
 {
  //TODO
 }

 void renderNewTool()
 {
  //TODO
 }

 void renderAvaliableUseBtn()
 {
  //TODO
 }

 void EventHappened()
 {
  newToolGotHandler(); // usage, fill args if necessary
 }
}

def register_callback(self, cb):
 self.callbacks.append(cb)

# -*- coding: utf-8 -*-
from UIDataNotifier import UIDataEvent
import inspect

class UIBase(object):

 def __init__(self, in_scene_id):
  self.id = in_scene_id
  self.init_data_listeners()

 def init_data_listeners(self):
  """为所有标有@data_listener的成员函数注册事件监听器"""
  for listener_name, listener in inspect.getmembers(self, lambda f: hasattr(f, 'events')):
   for event in listener.events:
    event += listener

 def destroy(self):
  print '%s.destroy' % self.__class__.__name__
  UIDataEvent.clear()

def getmembers(object, predicate=None):
 """Return all members of an object as (name, value) pairs sorted by name.
 Optionally, only return members that satisfy a given predicate."""
 results = []
 for key in dir(object):
  try:
   value = getattr(object, key)
  except AttributeError:
   continue
  if not predicate or predicate(value):
   results.append((key, value))
 results.sort()
 return results

  for listener_name, listener in inspect.getmembers(self, lambda f: hasattr(f, 'events')):
   for event in listener.events:
    event += listener

# -*- coding: utf-8 -*-
from UIDataNotifier import *
from UIBase import UIBase

class UIScene(UIBase):

 def __init__(self, in_scene_id):
  super(UIScene, self).__init__(in_scene_id)

 @data_listener(OnItemAdded)
 def ui_render_red_point(self, item):
  print 'ui_render_red_point'

 @data_listener(OnItemAdded)
 def ui_render_new_tool(self, item):
  print 'ui_render_new_tool: ' + item

 @data_listener(OnItemAdded)
 def ui_render_avaliable_use_btn(self, item):
  print 'ui_render_avaliable_use_btn'

bag_ui_scene = UIScene(123)

# -*- coding: utf-8 -*-
import sys

def data_listener(*events):
 def wrapped_f(f):
  f.events = events
  return f
 return wrapped_f

class UIDataEvent(object):
 _events = []
 def __init__(self, name):
  self._name = name
  self._callbacks = []
  UIDataEvent._events.append(self)

 def __iadd__(self, cb):
  self._callbacks.append(cb)
  return self

 def __call__(self, *args, **kwargs):
  for cb in self._callbacks:
   try:
    cb(*args, **kwargs)
   except:
    ex = sys.exc_info()
    print "UIDataNotifier cb error, function:", cb.__name__, ex

 def __repr__(self):
  return 'UIDataEvent %s' % self._name

 @classmethod
 def clear(cls):
  """清空所有事件上的所有监听器，在销毁一个界面的时候调用"""
  for event in cls._events:
   event._cb = []

OnItemAdded = UIDataEvent('OnItemAdded')

# -*- coding: utf-8 -*-
from UIScene import UIScene
from UIDataNotifier import *

OnItemAdded('liu_xin_biao') #新道具流星镖获得事件发生了

ui_render_avaliable_use_btn
ui_render_new_tool: liu_xin_biao
ui_render_red_point

@data_listener(OnEventA, OnEventB)
def my_listener_method(arg1):
 ...