Question

我正在开发一个程序，该程序将创建一堆克隆，并且在克隆克隆后将其删除。我只希望它删除粘贴在磁带上的克隆。我在触摸事件监听器上遇到了问题。它说我正在尝试索引一个nil变量，但是我在程序的前面定义了它。

我尝试将变量更改为全局变量。

display.setDefault("background", 0, 0, 200)
math.randomseed(os.time())

local boat = display.newImage( "boatt.png" )
boat.x = 163
boat.y = 225

local score = 0
local spawnCnt = 0
local spawnTable = {}
local startTime = os.time()
local startTime2 = os.time()
local fish_tapped


local function spawn ()
    local obj = display.newImageRect("fishpic.png",70,70)
    obj.x = math.random(1, 300)
    obj.y = (0 - math.random(30, 400))
    obj.isDone = false
    -- Note: Second argument is function name without brakets
    obj:addEventListener("touch", touched()) --i added brackets to this
    return obj
end

local function onSpawn ()
spawnCnt = spawnCnt + 1
spawnTable[spawnCnt] = spawn()
end

local function movement (event)
-- SPAWN OBJECT USING TIMER
if os.time() - startTime >= 1 then 
onSpawn()
startTime = os.time()
end



-- MOVE OBJECT
if spawnCnt > 0 then
for i = 1, spawnCnt do 
if spawnTable[i].isDone == false then 
if spawnTable[i].y > 600 or spawnTable[i].fish_tapped == true then
spawnTable[i].y = 700
spawnTable[i].isDone = true
display.remove(self)
self = nil
else 
spawnTable[i].y = spawnTable[i].y + 4
end
end
end
end 
end

Runtime:addEventListener ("enterFrame",movement)



--when i tried to have touched() in the event listener for touch it said that i was calling a 
--nill value, so I made the funciton global. 
function touched( event )
    local obj = event.target
    obj.fish_tapped = true
end

Answer 1

尝试（未测试）

local function movement (event)
  ...
  -- Replace 
  -- if spawnTable[i].y > 600 or fish_tapped == true then
  -- with
  if spawnTable[i].y > 600 or spawnTable[i].fish_tapped == true then
  ...
end

local function touched( event )
    local obj = event.target
    obj.fish_tapped = true
end

local function spawn ()
    local obj = display.newImageRect("fishpic.png",70,70)
    obj.x = math.random(1, 300)
    obj.y = (0 - math.random(30, 400))
    obj.isDone = false
    -- Note: Second argument is function name without brakets
    obj:addEventListener("touch", touched) 
    return obj
end

了解更多：

触摸时如何删除克隆

1 个答案: