尝试对全局变量'event'进行索引（其为一个空值）。

我对Lua很陌生，试图查看其他帖子以解决类似的错误，但无法解决我的问题。

我试图使用alpha on orientation让我的数字对象消失，并出现适当的数字。 我添加了onOrientationLeft函数以及对它的侦听器。在这样做后，我收到了错误，无法弄清如何使其工作。我的代码中的注释将说明我试图做什么，请找到onOrientationLeft函数和链接到它的最后一个运行时。

pZeroButton = display.newImage ("0.png",100, 470 )
llZeroButton = display.newImage ("0.png", 200,200)
llZeroButton.alpha = 0

pOneButton = display.newImage ("1.png",56,420)

pTwoButton = display.newImage ("2.png",123.5, 420)

pThreeButton = display.newImage ("3.png",191,420)

pFourButton = display.newImage ("4.png",56,370)

pFiveButton = display.newImage ("5.png",123.5, 370)

pSixButton = display.newImage ("6.png",191,370)

pSevenButton = display.newImage ("7.png",56,320 )

pEightButton = display.newImage ("8.png",123.5,320)

pNineButton = display.newImage ("9.png", 191, 320)

function onOrientationLeft ()
if (event.type == "landscapeRight") then
    print ("Test if this function onOrientationLeft is working properly")
end
end

• [[我添加了这个函数，试图使函数打印字符串，但是每次我在coronaSDK模拟器中旋转电话时，我都会得到错误尝试将全局‘event’（一个空值）索引]

function calculateZero(number)
local pZeroButton = display.newText (0, 300,30,nil,38)
pZeroButton: setFillColor (0,0,0)
return
end

function calculateOne(number)
local pOneButton = display.newText (1, 300,30,nil,38)
pOneButton: setFillColor (0,0,0)
return
end

function calculateTwo(number)
local pTwoButton = display.newText (2, 300,30,nil,38)
pTwoButton: setFillColor (0,0,0)
return
end

function calculateThree(number)
local pThreeButton = display.newText (3, 300,30,nil,38)
pThreeButton: setFillColor (0,0,0)
return
end

function calculateFour(number)
local pFourButton = display.newText (4, 300,30,nil,38)
pFourButton: setFillColor (0,0,0)
return
end

function calculateFive(number)
local pFiveButton = display.newText (5, 300,30,nil,38)
pFiveButton: setFillColor (0,0,0)
return
end

function calculateSix(number)
local pSixButton = display.newText (6, 300,30,nil,38)
pSixButton: setFillColor (0,0,0)
return
end

function calculateSeven(number)
local pSevenButton = display.newText (7, 300,30,nil,38)
pSevenButton: setFillColor (0,0,0)
return
end

function calculateEight(number)
local pEightButton = display.newText (8, 300,30,nil,38)
pEightButton: setFillColor (0,0,0)
return
end

function calculateNine(number)
local pNineButton = display.newText (9, 300,30,nil,38)
pNineButton: setFillColor (0,0,0)
return
end

pZeroButton : addEventListener ("tap", calculateZero)

pOneButton : addEventListener ("tap", calculateOne)

pTwoButton : addEventListener ("tap", calculateTwo)

pThreeButton : addEventListener ("tap", calculateThree)

pFourButton : addEventListener ("tap", calculateFour)

pFiveButton : addEventListener ("tap", calculateFive)

pSixButton : addEventListener ("tap", calculateSix)

pSevenButton : addEventListener ("tap", calculateSeven)

pEightButton : addEventListener ("tap", calculateEight)

pNineButton : addEventListener ("tap", calculateNine)

Runtime : addEventListener ("orientation", onOrientationLeft)