Storyboard.gotoScene() Runtime error on key listener

Solar2D Composer
#1

Hello everyone.

I am building a game using Storyboard that has 3 scenes (titleScene, selectLevelScene and playScene).

I can navigate between them without a problem tapping on the on-screen buttons.

I am trying to handle the Android hardware “back” and “menu” buttons to go back to the previous scene as the on-screen buttons do. When I try to do this i get this error and the screen turns black and accepts no other input:

Runtime error ?:0: attempt to index field 'contentBounds' (a nil value) main.lua:191: in function 'toScene' main.lua:215: in function '\_listener'

At line 191 there is a storyboard.gotoScene function call.

At line 215 is the function call from the onKeyEvent listener function that eventually calls the gotoScene function (code below).

I personally did not used the ‘contentBounds’ in this game. I am thinking maybe a build-in function uses is.

Here is the function that I use to navigate between scenes located in main.lua:

[lua]

function toScene(sceneName)      storyboard.purgeScene(storyboard.getCurrentSceneName())     storyboard.gotoScene( sceneName, "crossFade", 600) -- this is line 191 end

[/lua]

I always make sure that sceneName parameter is not equal to storyboard.getCurrentSceneName().

Here is the code that I use to handle key events located in main.lua:

[lua]

local function onKeyEvent( event )     local returnValue = false     local keyPhase = event.phase     local keyName = event.keyName     if storyboard.getCurrentSceneName() ~= nil and keyName ~= nil and keyPhase ~= nil then         if "back" == keyName or "menu" == keyName then             if "up" == keyPhase then                 returnValue = true                 if "titleScene" == storyboard.getCurrentSceneName() and "back" == keyName then                     local alert = native.showAlert( "Confirmation", "Are you sure you want to exit?", { "Yes", "No" }, onExitAlertAction )                 elseif "selectLevelScene" == storyboard.getCurrentSceneName() then                     toScene("titleScene") -- this is line 215                 elseif "playScene" == storyboard.getCurrentSceneName() then                     toScene("selectLevelScene")                 end             end         end     end     return returnValue end Runtime:addEventListener( "key", onKeyEvent )

[/lua]

The onKeyEvent function works great, in that I print()ed the key’s name, phase and the current scene the game finds itself successfully. The alert and exit works as well. Just the changing of the scene when I press the “back” or “menu” button (gotoScene()) doesn’t work.

I searched the Corona forums and on google for a few days to find solution but couldn’t.

I tried to add the runtime event listener in every scene on the enterScene() and remove it on the exitScene(), same error.

I tried to remove all the object event listeners on the exitScene() even though I heard that they will automatically be removed, same error.

There are a few others having this problem and I am not sure how they fixed it.

Here are a few links I read:

http://forums.coronalabs.com/index.php?app=core&module=search&section=search&do=search&fromsearch=1

http://forums.coronalabs.com/topic/26256-bug-with-storyboard-when-using-gotoscene/?hl=%2Bruntime+%2Berror+%2Bcontentbounds

After I find an answer, from here or elsewhere I will post it here, maybe it would be of some help for someone.

Thank you.

#2

Can you put in some print statements and see if what the results of your call to .getCurrentSceneName() is?  You also probably should not try and purge the scene you are currently in.  It’s a little hard to transition it off screen when it doesn’t exist.  I found it best to purge the scene you are going to to make sure it’s createScene fires.

#3

Thank you for your answer Rob. You were right, I removed the purgeScene(), and the gotoScene() works now. It is strange since the same code worked fine when pressing on a on-screen button, but when I handled the hardware buttons it gave me an error. For anyone interested the toScene() function became:

[lua]

function toScene(sceneName)     storyboard.gotoScene( sceneName, "crossFade", 600) end

[/lua]

And I handled the scene purging by enabling purgeOnSceneChange:

[lua]

storyboard.purgeOnSceneChange = true

[/lua]

This works great for me. Thank you again Rob.

#4

Can you put in some print statements and see if what the results of your call to .getCurrentSceneName() is?  You also probably should not try and purge the scene you are currently in.  It’s a little hard to transition it off screen when it doesn’t exist.  I found it best to purge the scene you are going to to make sure it’s createScene fires.

#5

Thank you for your answer Rob. You were right, I removed the purgeScene(), and the gotoScene() works now. It is strange since the same code worked fine when pressing on a on-screen button, but when I handled the hardware buttons it gave me an error. For anyone interested the toScene() function became:

[lua]

function toScene(sceneName)     storyboard.gotoScene( sceneName, "crossFade", 600) end

[/lua]

And I handled the scene purging by enabling purgeOnSceneChange:

[lua]

storyboard.purgeOnSceneChange = true

[/lua]

This works great for me. Thank you again Rob.