CODEWITHSUNDEEP
luacoronasdk
TheNotMe
TheNotMe

Reputation: 1058

Corona Storyboard, declaring an object then making it moveable, nil value attempt

I am creating a game, and in level 1 I want to load a few images that represent letters, and I want to add functionalities to them. One of them is the ability to move them.

So inside my enterScene is

function scene:enterScene(event)
...
    letA = display.newImage("media/letters/A.png", display.contentWidth/4 - 20, display.contentHeight/5 - 18)

    letC = display.newImage("media/letters/C.png", display.contentWidth/4 + 35, display.contentHeight/5 - 18)
    letR= display.newImage("media/letters/R.png", display.contentWidth/4 + 90, display.contentHeight/5 - 18)
    letE=display.newImage("media/letters/E.png", display.contentWidth/4 + 145, display.contentHeight/5 - 18)

    screenGroup:insert(letA)
    screenGroup:insert(letC)
    screenGroup:insert(letR)
    screenGroup:insert(letE)

    letA:addEventListener("touch", letA)
    letC:addEventListener("touch", letC)
    letR:addEventListener("touch", letR)
    letE:addEventListener("touch", letE)

now I added the moving function for letA, which is

function letA:touch(event)

    if event.phase=="began" then
        display.getCurrentStage():setFocus(self, event.id)
        self.isFocus = true

        self.markX = self.x
        self.markY = self.y

        elseif self.isFocus then
            if event.phase=="moved" then
                self.x = event.x - event.xStart + self.markX
                self.y = event.y - event.yStart + self.markY
            elseif event.phase=="ended" or event.phase == "cancelled" then
                display.getCurrentStage():setFocus(self,nil)
                self.isFocus = false
            end
        end

        return true
end

Then when I try to get into the scene it gives me an error to the line of function letA:touch(event), it says "attempt to index global 'letA'.

What do I do then? I designed it like that because I want it when the user clicks Play, it would load the letters, and if he presses back, it will unload them from screen.

Upvotes: 0

Views: 194

Answers (1)

NaviRamyle
NaviRamyle

Reputation: 4007

You can do this instead, you declare the touch function via ":" (colon) which letA or the other objects are not tables.

local letA = display.newImage("media/letters/A.png", display.contentWidth/4 - 20, display.contentHeight/5 - 18)

letA.touch = function(self,event)

    if event.phase=="began" then
        display.getCurrentStage():setFocus(self, event.id)
        self.isFocus = true

        self.markX = self.x
        self.markY = self.y

    elseif self.isFocus then
        if event.phase=="moved" then
            self.x = event.x - event.xStart + self.markX
            self.y = event.y - event.yStart + self.markY
        elseif event.phase=="ended" or event.phase == "cancelled" then
            display.getCurrentStage():setFocus(self,nil)
            self.isFocus = false
        end
    end

    return true
end


letA:addEventListener("touch")

Upvotes: 1

Related Questions