Attempt to index upvalue 'item1' (a nil value)

Solar2D General Questions/Discussion
#1

In my game, I am pulling two of the same item from a matchimgs{} table and placing them into separate objects (item1 and item2) in order to display one of each on opposite sides of the screen. The reason I created two separate ones is because item1 affects Player1’s score; item2 affects Player2’s score.

My problem is that for whatever reason, item1 sometimes becomes nil, even though I am just telling it to pull any one of the 12 items from my matchimgs{} table. Sometimes I have no problems many times in a row, other times it gets to the line saying “item1:scale(.5, .5)” and throws this exception:

Attempt to index upvalue ‘item1’ (a nil value)

local matchimgs = {     "images/items/beachball.png",     "images/items/bread.png",      "images/items/carrot.png",      "images/items/cheese.png",     "images/items/diamond.png",     "images/items/eggs.png",     "images/items/flower\_red.png",     "images/items/lettuce.png",     "images/items/pineapple.png",     "images/items/star.png",     "images/items/sunglasses.png",     "images/items/watermelon.png" };

if gameIsActive == true then             -- Add matching pair to the screen               randomMatchImage = matchimgs[math.random(#matchimgs)] --pick one item from matchimgs table above             math.randomseed(os.time())                          local function getItem1()                 if randomMatchImage == nil then                     randomMatchImage = matchimgs[math.random(#matchimgs)] --pick one item from matchimgs table above                 end                 file1 = randomMatchImage                                  item1 = display.newImage(file1)                 item1:scale(.5, .5)                 item1.x = math.random(100, centerX - 50)                 item1.y = math.random(75, display.contentHeight - 180)                 item1.name = "item1"                 item1:rotate(math.random(-45,315))                 item1.postCollision = onOverlap                 item1:addEventListener("tap", buttonListener)                  physics.addBody(item1, "static", {radius = 80, density = 1.0, friction = 50, bounce = 100, isSensor = false})                 group:insert(item1)             end                                      local function getItem2()                 file2 = file1 --make a copy of file1                                  item2 = display.newImage(file2)                 item2:scale(.5, .5)                 item2.x = math.random(centerX + 50, display.contentWidth - 100)                 item2.y = math.random(75, display.contentHeight - 180)                 item2.name = "item2"                 item2:rotate(math.random(-270,270))                 item2.postCollision = onOverlap                 item2:addEventListener("tap", buttonListener)                  physics.addBody(item2, "static", {radius = 80, density = 1.0, friction = 50, bounce = 100, isSensor = false})                 group:insert(item2)             end                                      getItem1()

Any clue why?

           

#2

Well, if item1:scale(.5,.5) fails, it suggests that item1 itself is nil (this is what the message means I think !), logically, this means the newImage() is failing. There are various possible reasons for this. file1 might not point to a legit filename, for example ; on the face of it this looks unlikely. The other thing is resources, you could be running out of memory. Are you removing the objects, are you removing the event listeners ?

What does the console log say ? IME if something like display.newImage() barfs you get lots of shout messages from Corona explaining why.  If it doesn’t come  up with anything, put some judicious asserts and prints in there, something like.

if item1 == nil then print(fileName1) end 

immediately before your scaling line.

#3

You da man, Paul! That was it. I looked at the Console window and it couldn’t find “beachball.png” because it was spelled “beachBall.png”. Now, no more crashing :slight_smile:

Thanks a million. BTW earlier it had me logged in as someone named “rafmab”. I have no idea why.

#4

No probs - I would always use lower case filenames in Corona for everything, some things work in the sim fine but not on a device if you don’t. Found this one the hard way :wink:

#5

Good to know! 

Thx again

#6

Well, if item1:scale(.5,.5) fails, it suggests that item1 itself is nil (this is what the message means I think !), logically, this means the newImage() is failing. There are various possible reasons for this. file1 might not point to a legit filename, for example ; on the face of it this looks unlikely. The other thing is resources, you could be running out of memory. Are you removing the objects, are you removing the event listeners ?

What does the console log say ? IME if something like display.newImage() barfs you get lots of shout messages from Corona explaining why.  If it doesn’t come  up with anything, put some judicious asserts and prints in there, something like.

if item1 == nil then print(fileName1) end 

immediately before your scaling line.

#7

You da man, Paul! That was it. I looked at the Console window and it couldn’t find “beachball.png” because it was spelled “beachBall.png”. Now, no more crashing :slight_smile:

Thanks a million. BTW earlier it had me logged in as someone named “rafmab”. I have no idea why.

#8

No probs - I would always use lower case filenames in Corona for everything, some things work in the sim fine but not on a device if you don’t. Found this one the hard way :wink:

#9

Good to know! 

Thx again