GTween onComplete question

Ghando

I'm having problems trying to get my head around "chaining" tweens one after the other.
I've tried using the onComplete value to call a function *after* the first tween has completed but it looks like it immediately runs when the tween is instantiated.

myShape.lua
-----------

myShape = gideros.class(Shape)   function myShape:init() local bitmap = Bitmap.new(Texture.new("square.png")) bitmap:setAnchorPoint(0.5, 0.5) self:addChild(bitmap) self.isFocus = false end   function myShape:doTween1() print("Inside doTween1") self.tween1 = GTween.new(self, 2, {x = _W /2 + 50, onComplete=self:doTween2()}) print("After GTween new") end   function myShape:doTween2() print("Inside doTween2") self.tween2 = GTween.new(self, 4, {rotation=90}) print("After Gtween 2 new") end

main.lua
-------

_W = application:getDeviceWidth() _H = application:getDeviceHeight()   local shape = myShape.new() stage:addChild(shape) shape:setX(_W/2) shape:setY(_H/2) shape:doTween1()

In the player the square immediately starts moving AND rotating and In the console I'm seeing:
Inside doTween1
Inside doTween2
After Gtween 2 new
After GTween new

So what am I doing wrong?

atilim

You've made a little mistake:
onComplete=self:doTween2()
should be
onComplete=self.doTween2

Ghando

Well spotted!
Comparing my code to MikeHart's Basic Shooter code I noticed I'd put the onComplete in the values rather than the params so now the function looks like:

function myShape:doTween1() print("Inside doTween1") self.tween1 = GTween.new(self, 2, {x = _W /2 + 50}, {onComplete=self.doTween2}) print("After GTween new") end

Ok, I'm almost there except now I get an error message and the console shows:

Inside doTween1
After GTween new
Inside doTween2
After Gtween 2 new
gtween.lua:386: attempt to call method 'get' (a nil value)
stack traceback:
gtween.lua:386: in function 'init2'
gtween.lua:212: in function 'setPosition'
gtween.lua:81: in function

atilim

oh yes, onComplete doesn't transfer the variable self to the function doTween2. This should work:

self.tween1 = GTween.new(self, 2, {x = _W /2 + 50}, {}) self.tween1:addEventListener("complete", self.doTween2, self) self.tween1.dispatchEvents = true

Edit: added dispatchEvents for future reference

Caroline

We've been discussing tweens here:
www.giderosmobile.com/forum/discussion/328/movie-clips-vs-gtween

atilim suggested this way of chaining:

And here is the correct way to chain tweens:

local tween1 = GTween.new(sprite, 1, {x = 240}, {}) local tween2 = GTween.new(sprite, 1, {y = 100}, {autoPlay = false}) local tween3 = GTween.new(sprite, 1, {alpha = 0}, {autoPlay = false}) tween1.nextTween = tween2 tween2.nextTween = tween3

Also this is same:

local tween3 = GTween.new(sprite, 1, {alpha = 0}, {autoPlay = false}) local tween2 = GTween.new(sprite, 1, {y = 100}, {autoPlay = false, nextTween = tween3}) local tween1 = GTween.new(sprite, 1, {x = 240}, {nextTween = tween2})

Ghando

Yup, that's it! So for anyone having a similar problem (eg, they also didn't read all the docs it's:

self.tween = GTween.new(...)
self.tween:addEventListener("complete", callback, parameter)
self.tween.dispatchEvents = true

Thanks atilim!

Ghando

Thanks Caroline,
I'm implementing a "pause tween on mouse_up" and so was trying to work out the best way to chain tweens but still make it easy to pause the currently running tween.

Turns out (at least in the 5 mins of testing I've just done) that if I throw each tween in a function I can just re-use the same self.tween variable which allows me to then do:

if (self.tween:isPaused() == false) then self.tween:setPaused(true) else self.tween:setPaused(false) end

and pause my animation regardless of what tween is running.