composer.removeScene() not working, other display objects not disappearing - lua

I'm working on an app in lua using Corona SDK.
I'm trying to go from my buildscene2 to my mainbuildscene, and I am successfully calling the new scene, but the objects from buildscene2 are not being removed. I have added the code to remove the previous scene, in the mainbuildscene.lua file. I've tried adding it in scene:create() and in scene:show(). Neither worked. This exact method has worked for me when transitioning from other scenes in the same application. What I've done here is created a function that uses composer.gotoScene("mainbuildscene") and then called the function when a button is pressed. I have a bunch of random prints in there just to see if the code is being read. It is.
I've looked for other people having this problem. Plenty of people have experienced this, but none of their solutions have worked for me. I've tried moving the event listener for when the next button is pressed to inside the snapTo function and then back out. If the listener is outside, it gives me an error.
Also, I know that the problem is not when I'm calling the new scene, because I put in a random picture to test if the objects from that scene would show up, and they did, except they were overtop of the objects from buildscene2. I even tried adding a function into the second scene that, when called, destroys the first scene. Didn't work.
Unless I did something wrong, all my display objects in buildscene2 are added to the group.
Here's my buildscene2 file. This is the file I'm transitioning away from and trying to destroy.
local composer = require( "composer" )
local scene = composer.newScene()
-- -----------------------------------------------------------------------------------------------------------------
-- All code outside of the listener functions will only be executed ONCE unless "composer.removeScene()" is called.
-- -----------------------------------------------------------------------------------------------------------------
-- local forward references should go here
-- ------------------------------------------------------------------------------
-- "scene:create()"
function scene:create( event )
local sceneGroup = self.view
-- Initialize the scene here.
-- Example: add display objects to "sceneGroup", add touch listeners, etc.
local group = display.newGroup()
composer.removeScene("thirdscene")
----------EMPTY BOXES
local itemFrame1=display.newImageRect("images/selection-box.png", 200,200)
itemFrame1.x=140
itemFrame1.y=130
group:insert(itemFrame1)
local itemFrame2=display.newImageRect("images/selection-box.png", 200,200)
itemFrame2.x=387
itemFrame2.y=130
group:insert(itemFrame2)
local itemFrame3=display.newImageRect("images/selection-box.png", 200,200)
itemFrame3.x=635
itemFrame3.y=130
group:insert(itemFrame3)
---------------HEADS
local robotHead=display.newImageRect("images/robot-head.png", 195,180)
robotHead.x=137
robotHead.y=130
robotHead.rotation = 180
robotHead.headtype=1
local rabbitHead=display.newImageRect("images/rabbit-head.png", 200, 180)
rabbitHead.x=387
rabbitHead.y=130
rabbitHead.rotation = 180
rabbitHead.headtype=2
local dinoHead=display.newImageRect("images/dino-head.png", 210, 190)
dinoHead.x=665
dinoHead.y=140
dinoHead.rotation = 180
dinoHead.headtype=3
-------------------OTHER
local nextButton=display.newImageRect("images/donebutton.png", 130, 130)
nextButton.x=140
nextButton.y=710
group:insert(nextButton)
nextButton.isVisible = false
local nextText=display.newText("NEXT", 100,100, native.systemFontBold, 40)
nextText.x=140
nextText.y=710
nextText:setTextColor (0,0,0)
group:insert(nextText)
function snapTo (event)
function makeVisible (event)
nextButton.isVisible = true
end
if event.phase == "began" then
event.target.markX = event.target.x -- store x location of object
event.target.markY = event.target.y -- store y location of object
torsoPlaced=event.target.torsoName
end
function addHeadsToGroup (event)
group:insert(robotHead)
group:insert(rabbitHead)
group:insert(dinoHead)
end
if event.phase == "moved" then
local x = (event.x - event.xStart) + event.target.markX
local y = (event.y - event.yStart) + event.target.markY
event.target.x, event.target.y = x, y -- move object based on calculations above
function demolish1 (event)
robotHead.x = 1000
robotHead.y = 900
robotHead.width = 10
robotHead.length = 10
robotHead.isVisible = false
group:insert(robotHead)
local staticRobot = display.newImageRect("images/robot-head.png", 195, 180)
staticRobot.x=137
staticRobot.y=130
staticRobot.rotation = 180
group:insert(staticRobot)
end
function demolish2 (event)
rabbitHead.x = 1000
rabbitHead.y = 900
rabbitHead.width = 10
rabbitHead.length = 10
rabbitHead.isVisible = false
group:insert(rabbitHead)
local staticRabbit = display.newImageRect("images/rabbit-head.png", 200, 180)
staticRabbit.x=387
staticRabbit.y=130
staticRabbit.rotation = 180
group:insert(staticRabbit)
end
function demolish3 (event)
dinoHead.x = 1000
dinoHead.y = 900
dinoHead.width = 10
dinoHead.length = 10
dinoHead.isVisible = false
group:insert(dinoHead)
local staticDino = display.newImageRect("images/dino-head.png", 210, 190)
staticDino.x=665
staticDino.y=140
staticDino.rotation = 180
group:insert(staticDino)
end
if (event.target.headtype == 1) then
event.target.width = 220
event.target.height = 200
if event.target.y > 400 then
event.target.isVisible = false
local newHead1 = display.newImageRect("images/robot-head.png",220, 200)
newHead1.x=150
newHead1.y=500
newHead1.rotation = 270
end
addHeadsToGroup()
makeVisible()
demolish2()
demolish3()
end
if (event.target.headtype == 2) then
event.target.width = 340
event.target.height = 240
if event.target.y > 400 then
event.target.isVisible = false
local newHead2 = display.newImageRect("images/rabbit-head.png",340, 240)
newHead2.x=140
newHead2.y=500
newHead2.rotation = 270
end
addHeadsToGroup()
makeVisible()
demolish1()
demolish3()
end
if (event.target.headtype == 3) then
event.target.width = 280
event.target.height = 250
if event.target.y > 400 then
event.target.isVisible = false
local newHead3 = display.newImageRect("images/dino-head.png",280, 250)
newHead3.x=140
newHead3.y=540
newHead3.rotation = 270
end
addHeadsToGroup()
makeVisible()
demolish1()
demolish2()
end
local function nextButtonClicked2 (event)
if event.phase=="ended" then
function sceneChange (event)
composer.gotoScene("mainbuildscene")
print("jererefs")
end
print("egsijegij")
sceneChange()
end
end
nextButton:addEventListener("touch", nextButtonClicked2)
end
end--end of snapTo
robotHead:addEventListener( "touch", snapTo)
rabbitHead:addEventListener( "touch", snapTo)
dinoHead:addEventListener("touch", snapTo)
end -- end
-- "scene:show()"
function scene:show( event )
local sceneGroup = self.view
local phase = event.phase
if ( phase == "will" ) then
-- Called when the scene is still off screen (but is about to come on screen).
elseif ( phase == "did" ) then
-- Called when the scene is now on screen.
-- Insert code here to make the scene come alive.
-- Example: start timers, begin animation, play audio, etc.
end
end
-- "scene:hide()"
function scene:hide( event )
local sceneGroup = self.view
local phase = event.phase
if ( phase == "will" ) then
-- Called when the scene is on screen (but is about to go off screen).
-- Insert code here to "pause" the scene.
-- Example: stop timers, stop animation, stop audio, etc.
elseif ( phase == "did" ) then
-- Called immediately after scene goes off screen.
end
end
-- "scene:destroy()"
function scene:destroy( event )
local sceneGroup = self.view
-- Called prior to the removal of scene's view ("sceneGroup").
-- Insert code here to clean up the scene.
-- Example: remove display objects, save state, etc.
end
---------------------------------------------------------------------------------
-- Listener setup
scene:addEventListener( "create", scene )
scene:addEventListener( "show", scene )
scene:addEventListener( "hide", scene )
scene:addEventListener( "destroy", scene )
-- ------------------------------------------------------------------ -------------
return scene
Here's my mainbuildscene file, the file I'm trying to load. It's loading in but the previous scene isn't going away.
local composer = require( "composer" )
local scene = composer.newScene()
-- -----------------------------------------------------------------------------------------------------------------
-- All code outside of the listener functions will only be executed ONCE unless "composer.removeScene()" is called.
-- -----------------------------------------------------------------------------------------------------------------
-- local forward references should go here
-- -------------------------------------------------------------------------------
-- "scene:create()"
function scene:create( event )
local sceneGroup = self.view
function removeTheScene (event)
print("this is not working, unless it is...?")
composer.removeScene("buildscene2")
end
removeTheScene()
-- Initialize the scene here.
-- Example: add display objects to "sceneGroup", add touch listeners, etc.
local group=display.newGroup()
--
--
local picture=display.newImageRect("images/bee-torso.png", 100, 100)
picture.x=display.contentCenterX
picture.y=display.contentCenterY
group:insert(picture)
end
-- "scene:show()"
function scene:show( event )
local sceneGroup = self.view
local phase = event.phase
if ( phase == "will" ) then
-- Called when the scene is still off screen (but is about to come on screen).
elseif ( phase == "did" ) then
-- Called when the scene is now on screen.
-- Insert code here to make the scene come alive.
-- Example: start timers, begin animation, play audio, etc.
end
end
-- "scene:hide()"
function scene:hide( event )
local sceneGroup = self.view
local phase = event.phase
if ( phase == "will" ) then
-- Called when the scene is on screen (but is about to go off screen).
-- Insert code here to "pause" the scene.
-- Example: stop timers, stop animation, stop audio, etc.
elseif ( phase == "did" ) then
-- Called immediately after scene goes off screen.
end
end
-- "scene:destroy()"
function scene:destroy( event )
local sceneGroup = self.view
-- Called prior to the removal of scene's view ("sceneGroup").
-- Insert code here to clean up the scene.
-- Example: remove display objects, save state, etc.
end
-- -------------------------------------------------------------------------------
-- Listener setup
scene:addEventListener( "create", scene )
scene:addEventListener( "show", scene )
scene:addEventListener( "hide", scene )
scene:addEventListener( "destroy", scene )
-- -------------------------------------------------------------------------------
return scene
Please let me know what I did wrong or give me any advice you can. Thanks for reading.

You must add them to "sceneGroup". You are adding all the object into your own group but they should be added to the "sceneGroup".
In buildscene2.lua remove these lines:
local group = display.newGroup()
composer.removeScene("thirdscene")
And make sure you add all your display object into the sceneGroup, and not the group:
Change this group:insert(itemFrame1) to this sceneGroup:insert(itemFrame1) but for all your display objects and on all your scenes.
If you're planning to reuse the scene (i.e. being able to go back and forth) you don't need to use the removeScene because Corona handles all the display objects belonging to the scenes i.e. when you go from Scene A to Scene B Corona will automatically move away the display objects belonging to Scene A from the screen and move the display objects belonging to Scene B to the screen.

Related

Corona SDK composer - changing scenes doesn't work

I have a little problem with corona SDK composer API. I got 3 .lua files- main.lua, character.lua and job.lua. The problem is, when I run the game, it automatically transits to character.lua and everything's fine. Then I'm transiting to job.lua and it works as well, but when I'm trying to come back to character.lua- nothing happens (the background doesn't change).That's how it look like:
main.lua:
local composer = require("composer")
composer.gotoScene("character")
character.lua:
local composer = require( "composer" )
local scene = composer.newScene()
-- -----------------------------------------------------------------------------------------------------------------
-- All code outside of the listener functions will only be executed ONCE unless "composer.removeScene()" is called.
-- -----------------------------------------------------------------------------------------------------------------
-- local forward references should go here
-- -------------------------------------------------------------------------------
-- "scene:create()"
function scene:create( event )
local sceneGroup = self.view
-- Initialize the scene here.
-- Example: add display objects to "sceneGroup", add touch listeners, etc.
local widget = require("widget")
local bottomTabButtons ={
{ width=32, height=32, defaultFile="character.png", overFile="character_active.png", selected="true"},
{ width=32, height=32, defaultFile="job.png", overFile="job_active.png", onPress=function() composer.gotoScene( "job" )end},
}
local bottomBar = widget.newTabBar{
top = display.contentHeight-40,
buttons = bottomTabButtons
}
end
-- "scene:show()"
function scene:show( event )
local sceneGroup = self.view
local phase = event.phase
if ( phase == "will" ) then
-- Called when the scene is still off screen (but is about to come on screen).
elseif ( phase == "did" ) then
-- Called when the scene is now on screen.
-- Insert code here to make the scene come alive.
-- Example: start timers, begin animation, play audio, etc.
end
end
-- "scene:hide()"
function scene:hide( event )
local sceneGroup = self.view
local phase = event.phase
if ( phase == "will" ) then
-- Called when the scene is on screen (but is about to go off screen).
-- Insert code here to "pause" the scene.
-- Example: stop timers, stop animation, stop audio, etc.
elseif ( phase == "did" ) then
-- Called immediately after scene goes off screen.
end
end
-- "scene:destroy()"
function scene:destroy( event )
local sceneGroup = self.view
-- Called prior to the removal of scene's view ("sceneGroup").
-- Insert code here to clean up the scene.
-- Example: remove display objects, save state, etc.
end
-- -------------------------------------------------------------------------------
-- Listener setup
scene:addEventListener( "create", scene )
scene:addEventListener( "show", scene )
scene:addEventListener( "hide", scene )
scene:addEventListener( "destroy", scene )
-- -------------------------------------------------------------------------------
return scene
job.lua:
local composer = require( "composer" )
local widget = require("widget")
local scene = composer.newScene()
-- -----------------------------------------------------------------------------------------------------------------
-- All code outside of the listener functions will only be executed ONCE unless "composer.removeScene()" is called.
-- -----------------------------------------------------------------------------------------------------------------
-- local forward references should go here
-- -------------------------------------------------------------------------------
-- "scene:create()"
function scene:create( event )
local sceneGroup = self.view
-- Initialize the scene here.
-- Example: add display objects to "sceneGroup", add touch listeners, etc.
local background = display.newImage("background.png")
background.x=display.contentCenterX
background.y=display.contentCenterY
background.height=display.contentHeight
background.width=display.contentWidth
local function gotoCharacter(event)
composer.gotoScene("character")
print('asd')
end
local bottomTabButtons ={
{ width=32, height=32, defaultFile="character.png", overFile="character_active.png", onPress=function() composer.gotoScene( "character" ) end},
{ width=32, height=32, defaultFile="job.png", overFile="job_active.png", selected="true"},
}
local bottomBar = widget.newTabBar{
top = display.contentHeight-40,
buttons = bottomTabButtons
}
end
-- "scene:show()"
function scene:show( event )
local sceneGroup = self.view
local phase = event.phase
if ( phase == "will" ) then
-- Called when the scene is still off screen (but is about to come on screen).
elseif ( phase == "did" ) then
-- Called when the scene is now on screen.
-- Insert code here to make the scene come alive.
-- Example: start timers, begin animation, play audio, etc.
end
end
-- "scene:hide()"
function scene:hide( event )
local sceneGroup = self.view
local phase = event.phase
if ( phase == "will" ) then
-- Called when the scene is on screen (but is about to go off screen).
-- Insert code here to "pause" the scene.
-- Example: stop timers, stop animation, stop audio, etc.
elseif ( phase == "did" ) then
-- Called immediately after scene goes off screen.
end
end
-- "scene:destroy()"
function scene:destroy( event )
local sceneGroup = self.view
-- Called prior to the removal of scene's view ("sceneGroup").
-- Insert code here to clean up the scene.
-- Example: remove display objects, save state, etc.
end
-- -------------------------------------------------------------------------------
-- Listener setup
scene:addEventListener( "create", scene )
scene:addEventListener( "show", scene )
scene:addEventListener( "hide", scene )
scene:addEventListener( "destroy", scene )
-- -------------------------------------------------------------------------------
return scene
Thanks in advance!
The problem is your not inserting your display objects in to the scenegroup. Thats why its not getting deleted. Insert all your objects in to the scenegroup.
For example,
local background = display.newImage("background.png")
background.x=display.contentCenterX
background.y=display.contentCenterY
background.height=display.contentHeight
background.width=display.contentWidth
sceneGroup:insert(background)
--- This is the change. Same way insert all the objects in to this group.

corona composer background next scene not showing

I have a lot of difficulties with composer...it's not so easy!
My previous scene is "game" (game.lua) everything is ok
When i go to my scene "recolt" with this snippet inside my game lua :
local function goTo()
print("gotoscene")
composer.gotoScene( "recolt", { time = 1000, effect = "fromRight", params = params } )
end
timer.performWithDelay( 1000, goTo )
:The problem is that i see my previous scene behind my recolt scene and i can't see my background but i see my circle who's moving ??? however my sceneGroup is correct :
sceneGroup:insert(background,circle)
When i do :
sceneGroup:insert(circle,background)
I see my background who hide my previous scene and my circle. > behavior expected
What's wrong? i would like to see my background and my circle in y "recolt" scene. Could you help me ? Thanks a lot...Below the snippet "recolt.lua".
--recolt.lua
local composer = require( "composer" )
local scene = composer.newScene()
function scene:create( event )
local sceneGroup = self.view
params = event.params
local background=display.newImageRect("back02.png",display.contentWidth*.5,d isplay.contentHeight*.5,320,480)
background.x,background.y=display.contentWidth*.5,display.contentHeight*.5
background.xScale,background.yScale=2,2
background.alpha=1
local circle = display.newCircle(120,100,100)
sceneGroup:insert(background,circle)
timeT=150
local function tr4()
transition.to(circle,{time=timeT,x=200,y=300,alpha=1,transition=easing.linear, xScale=1,yScale=1})
end
local function tr3()
transition.to(circle,{time=200,x=100,y=300,transition=easing.linear, xScale=.2 ,yScale=.5,onComplete=tr4})
end
local function tr2()
transition.to(circle,{time=200,x=200,y=295,transition=easing.linear, xScale=.2 ,yScale=.2,alpha=.2,onComplete=tr3})
end
local function tr1()
transition.to(circle,{time=timeT,x=300,y=300,transition=easing.linear, xScale= .5,yScale=.5,onComplete=tr2})
end
timer.performWithDelay(700,tr1,-1)
end
function scene:show( event )
local sceneGroup = self.view
params = event.params
if event.phase == "did" then
--physics.start()
end
end
function scene:hide( event )
local sceneGroup = self.view
if event.phase == "will" then
--
-- Remove enterFrame listeners here
--
--physics.stop()
end
end
function scene:destroy( event )
local sceneGroup = self.view
end
---------------------------------------------------------------------------------
-- END OF YOUR IMPLEMENTATION
---------------------------------------------------------------------------------
scene:addEventListener( "create", scene )
scene:addEventListener( "show", scene )
scene:addEventListener( "hide", scene )
scene:addEventListener( "destroy", scene )
return scene
You need to check the docs: object:insert()
The problem is you can only add 1 object into the scene with insert() function, so you only need to change
sceneGroup:insert(background,circle)
to
sceneGroup:insert(background)
sceneGroup:insert(circle)
The order matters, the first object you create go back in the scene.

My buttons wont appear on the screen for some reason in Corona SDK

My buttons wont appear on the screen for some reason in Corona SDK here is my code what am I missing?
local composer = require( "composer" )
local scene = composer.newScene()
-- include Corona's "widget" library
local widget = require "widget"
-- Function to handle button events
local function handleButtonEvent( event )
if ( "ended" == event.phase ) then
print( "Button was pressed and released" )
end
end
-- forward declarations and other locals
local playBtn
-- 'onRelease' event listener for playBtn
local function onPlayBtnRelease()
-- go to levelSelect.lua scene
composer.gotoScene( "levelSelect", "fade", 500 )
return true -- indicates successful touch
end
-- Background
local sky = display.newImage ("startScreen/sky.png")
sky.x = display.contentWidth/2; sky.y = display.contentHeight/2;
-- Picture
local preston = display.newImage ("startScreen/PrestonArt.png")
preston:scale( 0.4, 0.4 )
preston.x = display.contentWidth/2; preston.y = display.contentHeight/2;
-- Labels
local learningLabel = display.newImage ("startScreen/Learning.png")
learningLabel:scale( 0.3, 0.3 )
learningLabel.x = 506; learningLabel.y = 170;
local centerLabel = display.newImage ("startScreen/Center.png")
centerLabel:scale( 0.3, 0.3 )
centerLabel.x = 506; centerLabel.y = 600;
function scene:create( event )
local sceneGroup = self.view
-- Called when the scene's view does not exist.
--
-- INSERT code here to initialize the scene
-- e.g. add display objects to 'sceneGroup', add touch listeners, etc.
-- create a widget button (which will loads levelSelect.lua on release)
playBtn = widget.newButton{
defaultFile = "startScreen/Play.png", --the "default" image file
overFile = "startScreen/Play-Over.png", --the "over" image file
width=240, height=120,
onRelease = onPlayBtnRelease -- event listener function
}
playBtn.x = 300; playBtn.y = 695;
-- all display objects must be inserted into group
sceneGroup:insert( playBtn )
end
function scene:show( event )
local sceneGroup = self.view
local phase = event.phase
if phase == "will" then
-- Called when the scene is still off screen and is about to move on screen
elseif phase == "did" then
-- Called when the scene is now on screen
--
-- INSERT code here to make the scene come alive
-- e.g. start timers, begin animation, play audio, etc.
end
end
function scene:hide( event )
local sceneGroup = self.view
local phase = event.phase
if event.phase == "will" then
-- Called when the scene is on screen and is about to move off screen
--
-- INSERT code here to pause the scene
-- e.g. stop timers, stop animation, unload sounds, etc.)
elseif phase == "did" then
-- Called when the scene is now off screen
end
end
function scene:destroy( event )
local sceneGroup = self.view
-- Called prior to the removal of scene's "view" (sceneGroup)
--
-- INSERT code here to cleanup the scene
-- e.g. remove display objects, remove touch listeners, save state, etc.
if playBtn then
playBtn:removeSelf() -- widgets must be manually removed
playBtn = nil
end
end
-- Listener setup
scene:addEventListener( "create", scene )
scene:addEventListener( "show", scene )
scene:addEventListener( "hide", scene )
scene:addEventListener( "destroy", scene )
return scene
My guesses are
Comment says go to level1.lua but it tries to go to levelSelect
Don't use upper case in file names (in general)
try removing "fade", 500 to see it it works
in levelselect.lua you did not return scene or did not handle scene:create
More code and info please

attempt to index global 'group' (a nil value) - lua

I am new to lua and corona sdk, and i am using the storyboard api to create an app. i have a main.lua which just sends the user to menu.lua. menu.lua code looks like this:
local storyboard = require( "storyboard" )
local scene = storyboard.newScene()
-- include Corona's "widget" library
local widget = require "widget"
-- forward declarations and other locals
local playBtn
-- 'onRelease' event listener for playBtn
local function onPlayBtnRelease()
-- go to level1.lua scene
storyboard.gotoScene( "level1", "fade", 500 )
return true -- indicates successful touch
end
-- Called when the scene's view does not exist:
function scene:createScene( event )
local group = self.view
-- display a background image
local background = display.newImageRect( "background.png", display.contentWidth, display.contentHeight )
background:setReferencePoint( display.TopLeftReferencePoint )
background.x, background.y = 0, 0
-- create/position logo/title image on upper-half of the screen
local titleLogo = display.newImageRect( "logo.png", 264, 42 )
titleLogo:setReferencePoint( display.CenterReferencePoint )
titleLogo.x = display.contentWidth * 0.5
titleLogo.y = 100
-- create a widget button (which will loads level1.lua on release)
playBtn = widget.newButton{
label="Play Now",
labelColor = { default={255}, over={128} },
fontSize = "40",
defaultFile="button.png",
overFile="button-over.png",
width=250, height=80,
onRelease = onPlayBtnRelease -- event listener function
}
playBtn:setReferencePoint( display.CenterReferencePoint )
playBtn.x = display.contentWidth*0.5
playBtn.y = display.contentHeight - 125
-- all display objects must be inserted into group
group:insert( background )
group:insert( titleLogo )
group:insert( playBtn )
end
-- Called immediately after scene has moved onscreen:
function scene:enterScene( event )
local group = self.view
-- INSERT code here (e.g. start timers, load audio, start listeners, etc.)
end
-- Called when scene is about to move offscreen:
function scene:exitScene( event )
local group = self.view
-- INSERT code here (e.g. stop timers, remove listenets, unload sounds, etc.)
end
-- If scene's view is removed, scene:destroyScene() will be called just prior to:
function scene:destroyScene( event )
local group = self.view
if playBtn then
playBtn:removeSelf() -- widgets must be manually removed
playBtn = nil
end
end
-- "createScene" event is dispatched if scene's view does not exist
scene:addEventListener( "createScene", scene )
-- "enterScene" event is dispatched whenever scene transition has finished
scene:addEventListener( "enterScene", scene )
-- "exitScene" event is dispatched whenever before next scene's transition begins
scene:addEventListener( "exitScene", scene )
-- "destroyScene" event is dispatched before view is unloaded, which can be
-- automatically unloaded in low memory situations, or explicitly via a call to
-- storyboard.purgeScene() or storyboard.removeScene().
scene:addEventListener( "destroyScene", scene )
-----------------------------------------------------------------------------------------
return scene
and this is my level1.lua:
-----------------------------------------------------------------------------------------
--
-- level1.lua
--
-----------------------------------------------------------------------------------------
local storyboard = require( "storyboard" )
local scene = storyboard.newScene()
-- include Corona's "physics" library
local physics = require "physics"
physics.start(); physics.pause()
--------------------------------------------
-- forward declarations and other locals
local screenW, screenH, halfW = display.contentWidth, display.contentHeight, display.contentWidth*0.5
-----------------------------------------------------------------------------------------
-- BEGINNING OF YOUR IMPLEMENTATION
--
-- NOTE: Code outside of listener functions (below) will only be executed once,
-- unless storyboard.removeScene() is called.
--
-----------------------------------------------------------------------------------------
-- Called when the scene's view does not exist:
function scene:createScene( event )
local group = self.view
-- create a grass object
local bar= display.newImage( "bar.png", 0, 398)
local function update( event )
local group = self.view
updateBackgrounds()
end
local background1 = display.newImage("images/bg.png")
background1.x = 240
background1.y = 160
local background2 = display.newImage("images/bg.png")
background2.x = 760
background2.y = 160
function updateBackgrounds()
local group = self.view
--near background movement
background1.y = background1.y - (3)
--if the sprite has moved off the screen move it back to the
--other side so it will move back on
if(background1.x < -239) then
background1.x = 760
end
background2.y = background2.y - (3)
if(background2.x < -239) then
background2.x = 760
end
end
--this is how we call the update function, make sure that this line comes after the
--actual function or it will not be able to find it
--timer.performWithDelay(how often it will run in milliseconds, function to call,
--how many times to call(-1 means forever))
timer.performWithDelay(1, update, -1)
end
-- all display objects must be inserted into group
group:insert( background1 )
group:insert( background2 )
group:insert( bar )
-- Called immediately after scene has moved onscreen:
function scene:enterScene( event )
local group = self.view
physics.start()
end
-- Called when scene is about to move offscreen:
function scene:exitScene( event )
local group = self.view
physics.stop()
end
-- If scene's view is removed, scene:destroyScene() will be called just prior to:
function scene:destroyScene( event )
local group = self.view
package.loaded[physics] = nil
physics = nil
end
-----------------------------------------------------------------------------------------
-- END OF YOUR IMPLEMENTATION
-----------------------------------------------------------------------------------------
-- "createScene" event is dispatched if scene's view does not exist
scene:addEventListener( "createScene", scene )
-- "enterScene" event is dispatched whenever scene transition has finished
scene:addEventListener( "enterScene", scene )
-- "exitScene" event is dispatched whenever before next scene's transition begins
scene:addEventListener( "exitScene", scene )
-- "destroyScene" event is dispatched before view is unloaded, which can be
-- automatically unloaded in low memory situations, or explicitly via a call to
-- storyboard.purgeScene() or storyboard.removeScene().
scene:addEventListener( "destroyScene", scene )
-----------------------------------------------------------------------------------------
return scene
And here is my error:
When you create the group variable in the updateBackgrounds() method, self.view is nil because self.view only exists in the methods createScene() and enterScene(). What I recommend to do is create a global variable on the beginning of the script called group and then on your createScene method just do group = self.view without the "local" identifier.
Something like this:
--begining of the script
local group
-- Called when the scene's view does not exist:
function scene:createScene( event )
group = self.view
end
this creates a variable called group that has the reference of the self.view variable through all the script.
Another good option is to create a new global group and add it to the self.view on the createScene() method, this keeps things clean.
local globalGroup
function scene:createScene(event)
local group = self.view
globalGroup = display.newGroup()
group:insert(globalGroup)
end
Hope this helps.
This might because functions are not ending properly. Check if you are ending each function in level1.lua.
You are calling a function with a timer, but that function doesn't have access to self.view. Use the "enterFrame" event on Runtime, this is called at every frame:
function scene:enterFrame(event)
local group = self.view
... stuff from update functions ...
end
Runtime.addEventListener("enterFrame", scene)
If you don't need every frame, but say every second frame, put a counter in scene:enterFrame. Or in scene:enterFrame compute how much time since last call to determine if update needed.
local group
Should become
group
so that it is indeed global. Adding the local makes the 'global' become a part of only the body, not the functions, vice versa. If you need Lua practice, Roblox is a good place to start. The provide libraries already in your scripts so that it is easier to code. Try it. ;)

Corona SDK Using nativ text field in storyboard

So, I have a program that is using the corona storyboard.
There is scene 1 where the user can type something in a textbox at and there is also another scene, scene 2 where I have some text. The problem is that when the user goes away from the scene with the textbox, the textbox still appears on the screen. I've tried using removeSelf() which does delete it. But the problem is that the textbox is gone forever if i use removeSelf(), even when the user goes back to scene 1, it's still gone!
How could I fix this? Here is the code for scene 1:
--
-- view1.lua
--
-----------------------------------------------------------------------------------------
local storyboard = require( "storyboard" )
local scene = storyboard.newScene()
function scene:createScene( event )
local group = self.view
local bg = display.newRect( 0, 0, display.contentWidth, display.contentHeight )
bg:setFillColor(0,255,0 ) -- green
local title = display.newText( "Second View", 0, 0, native.systemFont, 32 )
title:setTextColor( 0 ) -- black
title:setReferencePoint( display.CenterReferencePoint )
title.x = display.contentWidth * 0.5
title.y = 125
local summary = display.newText( "Loaded by the first tab 'onPress' listener\n— specified in the 'tabButtons' table.", 0, 0, 300, 300, native.systemFont, 14 )
summary:setTextColor( 0 ) -- black
summary:setReferencePoint( display.CenterReferencePoint )
summary.x = display.contentWidth * 0.5 + 10
summary.y = title.y + 215
local function textListener( event )
if ( event.phase == "began" ) then
-- user begins editing text field
print( event.text )
elseif ( event.phase == "ended" ) then
-- text field loses focus
elseif ( event.phase == "ended" or event.phase == "submitted" ) then
-- do something with defaulField's text
elseif ( event.phase == "editing" ) then
print( event.newCharacters )
print( event.oldText )
print( event.startPosition )
print( event.text )
end
end
-- Create our Text Field
defaultField = native.newTextField( 150, 150, 180, 30 )
defaultField:addEventListener( "userInput", textListener )
-- all objects must be added to group (e.g. self.view)
group:insert( bg )
group:insert( title )
group:insert( summary )
end
-- Called immediately after scene has moved onscreen:
function scene:enterScene( event )
local group = self.view
-- do nothing
end
-- Called when scene is about to move offscreen:
function scene:exitScene( event )
local group = self.view
-- INSERT code here (e.g. stop timers, remove listenets, unload sounds, etc.)
end
-- If scene's view is removed, scene:destroyScene() will be called just prior to:
function scene:destroyScene( event )
local group = self.view
-- INSERT code here (e.g. remove listeners, remove widgets, save state variables, etc.)
end
-----------------------------------------------------------------------------------------
-- END OF YOUR IMPLEMENTATION
-----------------------------------------------------------------------------------------
-- "createScene" event is dispatched if scene's view does not exist
scene:addEventListener( "createScene", scene )
-- "enterScene" event is dispatched whenever scene transition has finished
scene:addEventListener( "enterScene", scene )
-- "exitScene" event is dispatched whenever before next scene's transition begins
scene:addEventListener( "exitScene", scene )
-- "destroyScene" event is dispatched before view is unloaded, which can be
-- automatically unloaded in low memory situations, or explicitly via a call to
-- storyboard.purgeScene() or storyboard.removeScene().
scene:addEventListener( "destroyScene", scene )
-----------------------------------------------------------------------------------------
return scene
So maybe you could use alpha to hide all elements in group?
group.alpha=0
You need to add the text box on the scene:enterScene method and remove it on the scene:exitScene.
Corona calls createScene only once, when creating the scene, but it calls enterScene and exitScene when the scene moves in or out of the stack. These are the places to create/remove elements.
For more information about screen management in corona you can read this. It's main focus is about cleaning up resources used in a scene and the examples are about sounds, but it applies to what you're trying to do and explains a little the Scene Management in Corona.

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