我有C#背景,刚刚开始用Ruby语言编程。问题是,我需要知道如何在我的类中引发事件,以便在需要发生事情时触发各种观察器。
问题是我写的关于Ruby的书甚至没有提到事件,更不用说提供例子了。有人能帮我吗?
发布于 2009-03-03 05:25:28
我试着用Ruby编写了一个GUI库,只用了一点C,主要是Ruby。它最终变得如此缓慢,我放弃了,从来没有发布过它。但是我为它写了一个事件系统,我试着让它比C#的更容易。我重写了几次,使它更容易使用。我希望它能有所帮助。
class EventHandlerArray < Array
def add_handler(code=nil, &block)
if(code)
push(code)
else
push(block)
end
end
def add
raise "error"
end
def remove_handler(code)
delete(code)
end
def fire(e)
reverse_each { |handler| handler.call(e) }
end
end
# with this, you can do:
# event.add_handler
# event.remove_handler
# event.fire (usually never used)
# fire_event
# when_event
# You just need to call the events method and call super to initialize the events:
# class MyControl
# events :mouse_down, :mouse_up,
# :mouse_enter, :mouse_leave
# def initialize
# super
# end
# def when_mouse_up(e)
# # do something
# end
# end
# control = MyControl.new
# control.mouse_down.add_handler {
# puts "Mouse down"
# }
# As you can see, you can redefine when_event in a class to handle the event.
# The handlers are called first, and then the when_event method if a handler didn't
# set e.handled to true. If you need when_event to be called before the handlers,
# override fire_event and call when_event before event.fire. This is what painting
# does, for handlers should paint after the control.
# class SubControl < MyControl
# def when_mouse_down(e)
# super
# # do something
# end
# end
def events(*symbols)
# NOTE: Module#method_added
# create a module and 'include' it
modName = name+"Events"
initStr = Array.new
readerStr = Array.new
methodsStr = Array.new
symbols.each { |sym|
name = sym.to_s
initStr << %Q{
@#{name} = EventHandlerArray.new
}
readerStr << ":#{name}"
methodsStr << %Q{
def fire_#{name}(e)
@#{name}.fire(e)
when_#{name}(e) if(!e.handled?)
end
def when_#{name}(e)
end
}
}
eval %Q{
module #{modName}
def initialize(*args)
begin
super(*args)
rescue NoMethodError; end
#{initStr.join}
end
#{"attr_reader "+readerStr.join(', ')}
#{methodsStr.join}
end
include #{modName}
}
end
class Event
attr_writer :handled
def initialize(sender)
@sender = @sender
@handled = false
end
def handled?; @handled; end
end
发布于 2009-03-03 08:22:32
这个问题已经得到了回答,但是如果你想看一下,标准库中有一个内置的observer。我过去曾在一个小游戏项目中使用过它,它运行得非常好。
发布于 2013-08-03 03:23:18
非常简单的Ruby监听器。这并不完全是.NET事件的替代品,但这是一个非常简单的侦听器的一个非常简单的示例。
module Listenable
def listeners() @listeners ||= [] end
def add_listener(listener)
listeners << listener
end
def remove_listener(listener)
listeners.delete listener
end
def notify_listeners(event_name, *args)
listeners.each do |listener|
if listener.respond_to? event_name
listener.__send__ event_name, *args
end
end
end
end
要使用以下命令:
class CowListenable
include Listenable
def speak
notify_listeners :spoken, 'moooo!'
end
end
class CowListener
def initialize(cow_listenable)
cow_listenable.add_listener self
end
def spoken(message)
puts "The cow said '#{message}'"
end
end
cow_listenable = CowListenable.new
CowListener.new(cow_listenable)
cow_listenable.speak
输出:
The cow said 'moooo!'
https://stackoverflow.com/questions/605169
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