Like as3-signals? Try signal.lua

This is my port of the core parts of Robert Penner's as3-signals to Lua for Corona:

https://github.com/joshtynjala/signal.lua

Nice!

Here's another implementation using the SimpleLuaClasses class.lua method

require "class"
--local mySignal = Signal()
--mySignal:add( myListener )
--mySignal:dispatch( 'something' )
Signal = class(function( self )
 
        self.callbacks = {}
end)
 
function Signal:dispatch( ... )
 
        if #self.callbacks > 0 then
                for i=1, #self.callbacks do
                        if self.callbacks[i] then
                                self.callbacks[i]( unpack( arg ))
                        end
                end
        end
end
 
function Signal:add( callback )
 
        table.insert( self.callbacks, callback )
end
 
function Signal:remove( callback )
 
        local i = #self.callbacks
        while i > 0 do
                if self.callbacks[i] == callback then
                        table.remove( self.callbacks, i )
                end
                i = i-1
    end
end
 
function Signal:removeAt( i )
 
        if i <= #self.callbacks then
                table.remove( self.callbacks, i )
        end
end
 
function Signal:removeAll()
 
        self.callbacks = {}
end
 
function Signal:dispose()
        
        self.callbacks = nil
end

And an implementation for native signals.

require "class"
--local mySignal = SignalNative( someDisplayObject, 'touch' )
--mySignal:add( myListener )
SignalNative = class(function( self, target, type, ... )
 
        self.target = target
        self.type = type
        self.arg = arg
        self.stopPropagation = false
        self.focus = true
        self[ self.type ] = SignalNative.Handler
        self.callbacks = {}
        self.active = false
end)
 
function SignalNative.Handler( self, event )
 
        if self.callbacks then
                if #self.callbacks > 0 then
                        self:dispatch( event, unpack( self.arg ) )
                end
                if self.type == 'touch' then
                        if self.focus and self.target ~= Runtime then
                                if 'began' == event.phase then
                                        display.getCurrentStage():setFocus( self.target )
                                elseif 'ended' == event.phase then
                                        display.getCurrentStage():setFocus( nil )
                                end
                        end
                end
        end
        return self.stopPropagation
end
 
function SignalNative:dispatch( ... )
 
        local callback
        if #self.callbacks > 0 then
                for i=1, #self.callbacks do
                        callback = self.callbacks[i]
                        if callback then
                                callback( unpack( arg ) )
                        end
                end
        end
end
 
function SignalNative:add( callback )
 
        table.insert( self.callbacks, callback )
        self:_addEventListener()
end
 
function SignalNative:remove( callback )
    
        local i = #self.callbacks
        while i > 0 do
                if self.callbacks[i] == callback then
                        table.remove( self.callbacks, i )
                end
                i = i-1
    end
        if #self.callbacks == 0 then
                self:_removeEventListener()
        end    
end
 
function SignalNative:removeAt( i )
 
        if i <= #self.callbacks then
                table.remove( self.callbacks, i )
        end
        if #self.callbacks == 0 then
                self:_removeEventListener()
        end 
end
 
function SignalNative:removeAll()
 
        self:_removeEventListener()
        self.callbacks = {}
end
 
function SignalNative:dispose()
        
        self[ self.type ] = nil
        self:removeAll()
        self.callbacks = nil
        self.target = nil
        self.type = nil
        self.arg = nil
end
 
function SignalNative:_removeEventListener()
 
        if self.active then
                self.active = false
                self.target:removeEventListener( self.type, self )
        end
end
 
function SignalNative:_addEventListener()
 
        if self.active == false then
                self.active = true
                self.target:addEventListener( self.type, self )
        end
end

What does this do exactly? I have not AS3 experience so some descriptive info will help a lot for pure LUA users like me.

A different approach to events.

http://johnlindquist.com/2010/01/21/as3-signals-tutorial/

It's an alternative to events. Basically, instead of subscribing to an event by passing a string to addEventListener, you subscribe to a signal, which is a first-class member of the object. You can also pass multiple arguments, instead of a single event object.

Instead of this:

local function eventHandler(event)
    print(event.arg1, event.arg2)
end
 
object:addEventListener("myEvent", eventHandler)

views:2026 update：2011/10/10 15:46:04


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