Main.lua：131尝试索引本地'up'（nil值）
嗨，希望您过得愉快。如果我犯的错误真的很简单，我表示歉意。我是lua的新手，现在仍在弄清楚。如果您有空余时间，请看一下代码。我得到的错误是：Main.lua：131尝试索引本地“ up”（一个nil值）我在第131行加上了我认为会引起星号错误的行，因此您不必计算每一行。我认为controls.displayGroup尚未正确初始化，但不确定如何修复。
local screenWidth = display.contentWidth
local screenHeight = display.contentHeight
local controllerWidth = screenWidth / 6
local rightMargin = 30
local maze = {
{ 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
{ 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1 },
{ 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1 },
{ 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1 },
{ 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1 },
{ 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0 },
{ 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1 },
{ 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1 },
{ 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1 },
{ 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1 },
}
maze.rows = table.getn(maze)
maze.columns = table.getn(maze[1])
maze.xStart, maze.yStart = 1, 1
maze.xFinish, maze.yFinish = 24, 7
local grid = {}
grid.xSquares = maze.columns
grid.ySquares = maze.rows
grid.totalWidth = screenWidth - controllerWidth - rightMargin
grid.squareSize = grid.totalWidth / grid.xSquares
grid.xStart = controllerWidth
grid.yStart = 60
grid.displayGroup = display.newGroup()
grid.displayGroup.x = grid.xStart
grid.displayGroup.y = grid.yStart
grid.functions = {
left = function(gridSquare)
if gridSquare.x == 0 then
return gridSquare
else
return grid[gridSquare.y][gridSquare.x - 1]
end
end,
right = function(gridSquare)
if gridSquare.x + 1 == grid.xSquares then
return gridSquare
else
return grid[gridSquare.y][gridSquare.x + 1]
end
end,
above = function(gridSquare)
if gridSquare.y == 0 then
return gridSquare
else
return grid[gridSquare.y - 1][gridSquare.x]
end
end,
below = function(gridSquare)
if gridSquare.y + 1 == grid.ySquares then
return gridSquare
else
return grid[gridSquare.y + 1][gridSquare.x]
end
end,
}
for y = 0, grid.ySquares - 1 do
grid[y] = {y = y}
for x = 0, grid.xSquares - 1 do
grid[y][x] = {x = x, y = y}
local rect = display.newRect(grid.displayGroup,
grid.squareSize * x, grid.squareSize * y,
grid.squareSize, grid.squareSize)
if maze[y + 1][x + 1] == 0 then
rect:setFillColor(245, 215, 98)
else
grid[y][x].wall = true
rect:setFillColor(32, 96, 32, 255)
end
grid[y][x].displayObject = rect
grid[y][x].left = grid.functions.left
grid[y][x].right = grid.functions.right
grid[y][x].above = grid.functions.above
grid[y][x].below = grid.functions.below
end
end
grid[maze.yStart - 1][maze.xStart - 1].start = true
grid[maze.yStart - 1][maze.xStart - 1].displayObject:setFillColor(192, 192, 255)
grid[maze.yFinish - 1][maze.xFinish - 1].displayObject:setFillColor(192, 128, 128)
grid[maze.yStart - 1][maze.xStart - 1].start = true
grid[maze.yFinish - 1][maze.xFinish - 1].finish = true
local runner = { image = "runner.png" }
function runner:enter(gridSquare)
if self.displayObject == nil then
self.displayObject = display.newImageRect(grid.displayGroup,
self.image, grid.squareSize, grid.squareSize)
self.displayObject:setFillColor(92, 92, 92)
end
self.displayObject.x = gridSquare.displayObject.x
self.displayObject.y = gridSquare.displayObject.y
self.gridSquare = gridSquare
self.x = gridSquare.x
self.y = gridSquare.y
if self.gridSquare.finish then
finish()
end
end
function runner:canEnter(gridSquare)
return gridSquare.wall == nil
end
local controlCenterX = controllerWidth / 2
local controlCenterY = screenHeight - screenHeight / 5
local controlCenterRadius = controllerWidth / 2 - rightMargin
local upDownWidth = 27
local upDownHeight = 60
local leftRightWidth = 60
local leftRightHeight = 27
local controls = {
up = {},
down = {},
right = {},
left = {},
}
****
controls.displayGroup = display.newGroup()
****
local circlePad = display.newCircle(controls.displayGroup,
controlCenterX, controlCenterY, controlCenterRadius)
circlePad:setFillColor(128, 128, 128)
*****
local up = display.newImageRect(controls.displayGroup, "arrow_up.png",
upDownWidth, upDownHeight)
up.x = controlCenterX
up.y = controlCenterY - upDownHeight / 2
controls.up.displayObject = up
*****
local down = display.newImageRect(controls.displayGroup, "arrow_down.png",
upDownWidth, upDownHeight)
down.x = controlCenterX
down.y = controlCenterY + upDownHeight / 2
controls.down.displayObject = down
local right = display.newImageRect(controls.displayGroup, "arrow_right.png",
leftRightWidth, leftRightHeight)
right.x = controlCenterX + leftRightWidth / 2
right.y = controlCenterY
controls.right.displayObject = right
local left = display.newImageRect(controls.displayGroup, "arrow_left.png",
leftRightWidth, leftRightHeight)
left.x = controlCenterX - leftRightWidth / 2
left.y = controlCenterY
controls.left.displayObject = left
controls.hide = function(controls)
controls.displayGroup.isVisible = false
end
controls.show = function(controls)
controls.displayGroup.isVisible = true
end
local function pressLeft(event)
if event.phase == "began" then
local nextSquare = runner.gridSquare:left()
if runner:canEnter(nextSquare) then
runner:enter(nextSquare)
end
end
end
local function pressRight(event)
if event.phase == "began" then
local nextSquare = runner.gridSquare:right()
if runner:canEnter(nextSquare) then
runner:enter(nextSquare)
end
end
end
local function pressUp(event)
if event.phase == "began" then
local nextSquare = runner.gridSquare:above()
if runner:canEnter(nextSquare) then
runner:enter(nextSquare)
end
end
end
local function pressDown(event)
if event.phase == "began" then
local nextSquare = runner.gridSquare:below()
if runner:canEnter(nextSquare) then
runner:enter(nextSquare)
end
end
end
controls.left.displayObject:addEventListener("touch", pressLeft)
controls.right.displayObject:addEventListener("touch", pressRight)
controls.up.displayObject:addEventListener("touch", pressUp)
controls.down.displayObject:addEventListener("touch", pressDown)
local startButton = {}
startButton.displayGroup = display.newGroup()
startButton.displayObject = display.newCircle(startButton.displayGroup,
controlCenterX, controlCenterY, controlCenterRadius)
startButton.displayObject.strokeWidth = 6
startButton.displayObject:setStrokeColor(244, 244, 64)
startButton.text = display.newText(startButton.displayGroup,
"Start", controlCenterX - controlCenterRadius + 20, controlCenterY - 18,
native.systemFont, 24)
startButton.text:setTextColor(0, 0, 0)
startButton.touch = function(event)
if event.phase == "began" then
startButton:hide()
start()
end
end
startButton.displayGroup:addEventListener("touch", startButton.touch)
startButton.show = function(button)
button.displayGroup.isVisible = true
end
startButton.hide = function(button)
button.displayGroup.isVisible = false
end
local playAgainButton = {}
playAgainButton.displayGroup = display.newGroup()
playAgainButton.displayObject = display.newCircle(playAgainButton.displayGroup,
controlCenterX, controlCenterY, controlCenterRadius)
playAgainButton.displayObject.strokeWidth = 6
playAgainButton.displayObject:setStrokeColor(244, 244, 64)
playAgainButton.text = display.newText(playAgainButton.displayGroup,
"Again", controlCenterX - controlCenterRadius + 20, controlCenterY - 18,
native.systemFont, 24)
playAgainButton.text:setTextColor(0, 0, 0)
playAgainButton.touch = function(event)
if event.phase == "began" then
playAgainButton:hide()
play()
end
end
playAgainButton.displayGroup:addEventListener("touch", playAgainButton.touch)
playAgainButton.show = startButton.show
playAgainButton.hide = startButton.hide
function play()
runner:enter(grid[maze.yStart - 1][maze.xStart - 1])
playAgainButton:hide()
controls:hide()
startButton:show()
end
function start()
controls:show()
end
function finish()
controls:hide()
playAgainButton:show()
end
play()
display.newImageRect将不返回任何内容，即变量nil，如果图像文件不存在，您可能已经通过检查控制台注意到了这一点，以解决此问题，就像将缺少的资产添加到项目文件夹！
欢迎使用堆栈溢出〜