Emitter.lua

local Emitter = class("Emitter")

function Emitter:ctor()
    self._callbacks = {}
end

-- 调整为只有一个事件回调
function Emitter:on(event, fn)
    -- if not self._callbacks[event] then
    self._callbacks[event] = {}
    -- end
    table.insert(self._callbacks[event],fn)
end
Emitter.addListener = Emitter.on

function Emitter:once(event, fn, args)
    function on()
        self:off(event,on)
        fn(args)
    end
    fn._off = on
    self:on(event,on)
    return self
end

function Emitter:off(event, fn)
    return self:removeListener(event,fn)
end

function Emitter:removeAllListener()
    self._callbacks = {}
    return self
end

function Emitter:removeListener(event, fn)
    local callbacks = self._callbacks[event]
    if not callbacks then
        return self
    end

    if not fn then
        self._callbacks[event] = nil
        return self
    end

    local i = table.indexOf(callbacks,fn._off or fn)
    if i then
        table.remove(callbacks,i)
    end

    return self
end

function Emitter:emit(event, args)
    printInfo("Emitter:emit event=%s",event)
    if type(args) ~= "table"  then
        args = {}
    end
    args.__event__ = event
    local callbacks = self._callbacks[event]
    if callbacks then
        for i=1,#callbacks do
            callbacks[i](args)
        end
    end

    return self
end

function Emitter:listeners(event)
    return self._callbacks[event] or {}
end

function Emitter:hasListeners(event)
    return #self.listeners(event) > 0
end

return Emitter