錯誤：試圖指數全局對象一個零值：電暈SDK

Question

，我發現了錯誤：

運行時錯誤 ......正stylr \文件\電暈項目\ happy_day \ game.lau：50 ：試圖指數全球 'city1'（一個零值）

我的代碼如下：

function scene:createScene(event) 

local screenGroup = self.view 

local background = display.newImage("background1.jpg") 

local city1 = display.newImage("bild.png") 
city1:setReferencePoint(display.BottomLeftReferencePoint) 
city1.x = 0 
city1.y = 640 
city1.speed = 1 

local city2 = display.newImage("bild.png") 
city2:setReferencePoint(display.BottomLeftReferencePoint) 
city2.x = 1136 
city2.y = 640 
city2.speed = 1 

local city3 = display.newImage("build2.png") 
city3:setReferencePoint(display.BottomLeftReferencePoint) 
city3.x = 0 
city3.y = 640 
city3.speed = 2 

local city4 = display.newImage("build2.png") 
city4:setReferencePoint(display.BottomLeftReferencePoint) 
city4.x = 1136 
city4.y = 640 
city4.speed = 2 
end 

function scene:enterScene(event) 

Runtime:addEventListener("touch", touchScreen) 
print(city1) 
city1.enterFrame = scrollCity 
Runtime:addEventListener("enterFrame", city1) 

city2.enterFrame = scrollCity 
Runtime:addEventListener("enterFrame", city2) 

city3.enterFrame = scrollCity 
Runtime:addEventListener("enterFrame", city3) 

city4.enterFrame = scrollCity 
Runtime:addEventListener("enterFrame", city4) 

end 

Answer 1

只是聲明local city1的createScene功能外，並創建city1爲：

local city1; 

function scene:createScene(event) 
    -- your code for localGroup and bg 

    city1 = display.newImage("bild.png") -- just create city1 as this 

    -- do the rest of your code 
end 

如果錯誤發生時要重新考慮其他城市（city2，3或4），請對所有這些方法執行相同的方法。

保留編碼................ :)