我对阅读newstyle vs oldstyle属性的差异感到困惑。在这个例子中:
此代码是否使用旧式方法修改属性?
Event()
self.__dict__.update(kw)
我是否使用getattr, getattr 或 getattribute ?
for Dispatcher.dispatch_to_parent()
class Event(object):
def __init__(self, name, kw={}):
self.name = name
self.__dict__.update(kw)
self.dict = dict(kw)
self.method_name = 'EVT_%s' % self.name
def __repr__(self):
return "<event>" % (self.name, self.dict)
class Dispatcher(object):
def add(self, other):
if isinstance(other, Dispatcher):
other.parent = self
else:
raise ValueError("%s is not a Dispatcher" % other)
def remove(self, other):
if isinstance(other, Dispatcher):
if other.parent is self:
del other.parent
else:
raise ValueError("%s is not my child." % other)
else:
raise ValueError("%s is not a Dispatcher" % other)
def dispatch(self, event):
method = getattr(self, event.method_name, None)
if method is not None:
return method(event)
else:
self.dispatch_to_parent(event)
def dispatch_to_parent(self, event):
parent = getattr(self, 'parent', None)
if parent is not None:
dispatch = getattr(parent, 'dispatch', None)
if dispatch is not None:
return dispatch(event)
class Root(Dispatcher):
def __init__(self):
Dispatcher.__init__(self)
self.focused_node = self
def focus(self, node):
if node is self.focused_node: return
print 'focusing on', node
self.focused_node.dispatch(Event('BLUR'))
self.focused_node = node
node.dispatch(Event('FOCUS'))
def blur(self, node):
self.focused_node = self
node.dispatch(Event('BLUR'))
def post(self, event_name, kw):
event = Event(event_name, kw)
return self.focused_node.dispatch(event)
if __name__ == "__main__":
class Button(Dispatcher):
def EVT_KeyDown(self, event):
return self
#create the root node, which is the receiver of all events.
r = Root()
#create a button node
b = Button()
#add the button node to the application
r.add(b)
#give the button node focus, it will now receive events
r.focus(b)
#post a KeyDown event, which the button will receive
print r.post('KeyDown')
#post a Quit event, which the button will not receive.
#this event will be passed onto the button parent
print r.post('Quit')
#the return value of the post method is the node which handled the event
答案 0 :(得分:3)
您不应直接更新实例字典,您将绕过自定义设置器。循环键并执行setattr。
答案 1 :(得分:0)
def post(self, event_name, kw):
行
由于使您能够接收dict作为参数,您需要在变量名称之前添加**:
def post(self, event_name, **kw):
event = Event(event_name, kw)
return self.focused_node.dispatch(event)