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对于让我发疯的错误,我会向您寻求帮助。
哦...我正在使用带有 Corona SDK 的 LUA 顺便说一句...
我正在创建一个船的实例。船正在被实例化,我可以访问它的属性,但我无法访问任何方法!!按照代码,我不知道该怎么做:
spaceship .lua:
require('gameConf')
spaceShip = {}
spaceShip.__index = spaceShip
function spaceShip:New(posX, posY, width, height)
local _spaceShip = nil
_spaceShip = {}
setmetatable(_spaceShip, spaceShip)
_spaceShip = display.newRect(posX - width/2, posY - height/2, width, height)
_spaceShip:setFillColor(140, 140, 140, 0)
_spaceShip.width = width
_spaceShip.height = height
local shipShape = { -width/2, -height/2, width/2, -height/2, width/2, height/2, -width/2, height/2 }
local shipShapeMaterial = { density = 1.0, friction = 1.0, bounce = 0.0 , shape = shipShape}
local shipMotor = { -width/2, height/3, width/2, height/3, width/2, height/2, -width/2, height/2 }
local shipMotorMaterial = { density = 1.0, friction = 1.0, bounce = 0.0 , shape = shipMotor}
physics.addBody( _spaceShip, shipShapeMaterial, shipMotorMaterial )
return _spaceShip
end
function spaceShip:log()
print("ship")
end
function spaceShip:applyFrontImpulse()
local angle = math.rad(self.rotation)
local xComp, yComp = math.cos(angle), -math.sin(angle)
local forceMag = 2
self:applyLinearImpulse(forceMag * xComp, forceMag * yComp, self.x, self.y)
end
require('camera')
require('gameConf')
require('meteor')
require('spaceShip')
-- Add Physics
local physics = require( "physics" )
physics.start()
physics.setDrawMode( "hybrid" )
physics.setGravity( 0, 0 )
-- Load camera
local camera = camera:New()
-- Containers
meteorManager = {}
shipManager = {}
-- Load Vector class
vector = require "vector"
-- Create one ship
local myShip = nil;
myShip = {}
myShip = spaceShip:New(600, 200, 30, 60)
table.insert(shipManager, myShip)
camera:insert(myShip)
myShip:log() <----- HERE IS THE ERROR
rest of the code...
2013-03-21 19:18:15.736 Corona Simulator[48347:707] Runtime error:
2013-03-21 19:18:15.737 Corona Simulator[48347:707] ...t/iOS/Deep Space Harvest/Deep Space Harvest/main.lua:28: attempt to call method 'log' (a nil value)
stack traceback:
[C]: in function 'log'
...t/iOS/Deep Space Harvest/Deep Space Harvest/main.lua:28: in main chunk
最佳答案
我怀疑这个问题是因为这个片段:
_spaceShip = {}
setmetatable(_spaceShip, spaceShip)
_spaceShip = display.newRect(posX - width/2, posY - height/2, width, height)
_spaceShip
上设置了元表,但随后为其分配了一个新值。此时,您分配的新值不具有您建立的元表关联,因为它是在值上(不是变量)。
setmetatable
之后
_spaceShip = display.newRect...
.
关于LUA 和电晕错误 : Attempt To Call Method ' ' (A Nil Value) - Driving Me Crazy,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/15560813/
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