我使用的是Corona SDK。我基本上试图这样做，当你点击箭头时，你被引导到另一个场景。出于某种原因，它引发了一个我无法理解的错误。
首先，它说我实施的暂停按钮有问题，所以我删除它以查看问题是否仍然存在。现在它表示该功能存在问题＆＃39;取消＆＃39;？！
错误：
?:0: attempt to index a nil value
stack trackback:
?: in function 'cancel'
scene3.lua:377: in function <scene3.lua.368>
?: in function DispatchEvent
?: in function ?
?: in function GoToScene
scene3.lua:74 in fuction <scene3.lua:63>
?: in function <?:221>
这是我的scene3.lua：
---------------------------------------------------------------------------------
--
-- scene3.lua
--
---------------------------------------------------------------------------------
local storyboard = require( "storyboard" )
local scene = storyboard.newScene()
system.activate("multitouch")
local physics = require ("physics")
physics.start()
local sound_pickup = audio.loadSound ("pickup.mp3")
local sound_drop = audio.loadSound ("drop.mp3")
local sound_pause = audio.loadSound ("pausebutton.mp3")
--local backgroundMusic = audio.loadStream("Backgroundmusic.mp3")
--local backgroundMusicChannel = audio.play( backgroundMusic, { channel=-1, loops=-100, fadein=5000 } )
---------------------------------------------------------------------------------
-- BEGINNING OF YOUR IMPLEMENTATION
---------------------------------------------------------------------------------
local image, text1, text2, text3, memTimer, pause, BedInfo
local function restarto( self, event )
if event.phase == "began" then
print("restarted")
audio.play(sound_click)
physics.pause()
return true
end
end
-- Called when the scene's view does not exist:
function scene:createScene( event )
--audio.play(backgroundMusic)
audio.play(backgroundMusic)
print( "3: createScene event" )
local screenGroup = self.view
image = display.newImage( screenGroup, "gamebackground.png" )
image.x = _W * 0.5
image.y = _H * 0.5
local function Gooutside( self, event )
if event.phase == "began" then
print( "Move outside mate" )
return true
end
end
local function ArrowMove( self, event )
if event.phase == "began" then
outside = display.newImage( screenGroup, "Gooutside.png" )
local group1 = display.newGroup()
group1:insert(outside)
outside.x = _W * 0.5
outside.y = _H * 0.9
outside.touch = Gooutside
outside:addEventListener( "touch", outside )
storyboard.gotoScene( "scene1", "fade", 1000 )
print( "Button Pressed to leave house" )
return true
end
end
-- Bounding walls, So player cannot walk off screen
local TopWall = display.newRect(_W * 0.5, 0, _W, 5)
local BottomWall = display.newRect(_W * 01, _H * 0, _W, 5)
local LeftWall = display.newRect(0, _H * 0.5, 5, _H)
local RightWall = display.newRect(_W, _H * 0.5, 5, _H)
local OutsideWall = display.newRect(_W * 0.5, _H * 0.8, _W, 5)
OutsideWall.rotation = 25
OutsideWall:setFillColor( 1,1,1,0)
local SideWall = display.newRect(_W * 0.8, _H * 0.8, _W, 5)
SideWall.rotation = -25
SideWall:setFillColor( 1,1,1,0)
local BackWall = display.newRect(_W * 0.8, _H * 0.5, _W, 5)
BackWall.rotation = 26
BackWall:setFillColor( 1,1,1,0)
local RightFloor = display.newRect(_W * 0.4, _H * 0.3, _W, 5)
RightFloor.rotation = -25
RightFloor:setFillColor( 1,1,1,0)
local Bed = display.newRect(_W * 0.3, _H * 0.3, 150, 100)
Bed.rotation = -35
Bed:setFillColor( 1,1,1,0)
--WALL/PLATFORM PHYSICS, STAT
physics.addBody(TopWall, "static",{density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} }) --binary 1
physics.addBody(BottomWall, "static", {density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} })
physics.addBody(LeftWall, "static", {density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} })
physics.addBody(RightWall, "static", {density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} })
physics.addBody(SideWall, "static", {density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} })
physics.addBody(OutsideWall, "static", {density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} })
physics.addBody(BackWall, "static", {density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} })
physics.addBody(RightFloor, "static", {density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} })
physics.addBody(Bed, "static", {density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} })
-- THE ON SPEAKER BECOMES THE OFF SPEAKER. DELETES THE ON SPEAKER AND
-- REPLACES IT WITH THE OFF SPEAKER
local function musicswitch( self, event )
if event.phase == "began" then
print("musicoff")
audio.play(sound_pause)
audio.pause("backgroundMusic", 1)
music:removeSelf()
music = nil
music2 = display.newImage( screenGroup, "speaker2.png" )
music2.x = _W * 0.9
music2.y = _H * 0.1
music2.xScale = 0.5
music2.yScale = 0.5
music2.touch = musicon
music2:addEventListener( "touch", music2 )
return true
end
end
-- THE ON SPEAKER BECOMES THE OFF SPEAKER. DELETES THE ON SPEAKER AND
-- REPLACES IT WITH THE OFF SPEAKER
local function musicson( self, event )
if event.phase == "began" then
print("musicon")
audio.play(sound_pause)
music2:removeSelf()
return true
end
end
-- kill music spawn
music = display.newImage( screenGroup, "speaker.png" )
music.x = _W * 0.9
music.y = _H * 0.1
music.xScale = 0.5
music.yScale = 0.5
music.touch = musicswitch
music:addEventListener( "touch", music )
-- Flag spawn
flag = display.newImage( screenGroup, "flag.png" )
flag.x = _W * 0.7
flag.y = _H * 0.14
flag.myName = "flag"
physics.addBody(flag, "static", {density = 90, friction = 900, bounce = 0.1,
filter = {categoryBits = 2, maskBits = 3} })
local function onCollision( event )
if ( event.phase == "began" ) then
win = display.newImage( screenGroup, "WINNER.png" )
win.x = _W * 0.55
win.y = _H * 0.5
win.xScale = 0.9
win.yScale = 1
print("Flag Hit")
physics.pause()
elseif ( event.phase == "ended" ) then
--print( "ended: " .. event.object1.flag .. " & " .. event.object2.spriteAsh )
end
end
flag:addEventListener( "collision", onCollision )
function reset(event)
if event.phase == "began" then
if paused == false then
timer.performWithDelay( 5000, function()
storyboard.reloadScene()
end, 1 )
audio.play(sound_pause)
elseif paused == true then
paused = false
end
end
end
--Add Bedroom
local Arrow = display.newImage( screenGroup, "Arrow.png" )
Arrow.x = _W * 0.4
Arrow.y = _H * 0.7
Arrow.yScale = 0.1
Arrow.xScale = 0.1
Arrow.rotation = -130
local group = display.newGroup()
group:insert(Arrow)
Arrow.touch = ArrowMove
Arrow:addEventListener("touch", Arrow)
Bedroom = display.newImage( screenGroup, "Bedroom.png" )
Bedroom.x = _W * 0.5
Bedroom.y = _H * 0.5
Bedroom.xScale = 1
Bedroom.yScale = 1
local
-- Restart Function
restart = display.newImage( screenGroup, "restartbutton.png" )
restart.x = _W * 0.5
restart.y = _H * 0.06
restart.xScale = 0.2
restart.yScale = 0.2
restart.touch = restartscene
restart:addEventListener("touch", reset)
text1 = display.newText( screenGroup, " ", _W * 0.5, 50, native.systemFontBold, 24 )
text2 = display.newText( screenGroup, " ", _W * 0.5, _H * 0.5, native.systemFont, 16 )
text3 = display.newText( screenGroup, " ", _W * 0.5, _H - 100, native.systemFontBold, 18 )
text3.isVisible = false
end
---------------------------------------------------------------------------------
-- CHARACTER PROPERTIES
---------------------------------------------------------------------------------
display.setDefault("magTextureFilter", "nearest")
local options =
{ --required parameters
width = 32,
height = 32,
numFrames = 20,
--optional parameters; used for dynamic resolution support
sheetContentWidth = 160, -- width of original 1x size of entire sheet
sheetContentHeight = 128 -- height of original 1x size of entire sheet
}
local sheetAsh = graphics.newImageSheet( "boy.png", options )
local sequenceData =
{
{ name="down_stand", start=1, count=1},
{ name="down_run", frames={2, 3, 4, 5}, time=400, loopCount=0, loopDirection = "bounce"},
{ name="left_stand", start=6, count=1},
{ name="left_run", frames={7, 8, 9, 10}, time=800, loopCount=0, loopDirection = "bounce"},
{ name="up_stand", start=11, count=1},
{ name="up_run", frames={12, 13, 14, 15}, time=1000, loopCount=0, loopDirection = "bounce"},
{ name="right_stand", start=16, count=1},
{ name="right_run", frames={17, 18, 19, 20}, time=800, loopCount=0, loopDirection = "bounce"},
}
local spriteAsh = display.newSprite( sheetAsh, sequenceData )
physics.addBody(spriteAsh, "dynamic", {density =1.5 , bounce = 0.5, radius = 28})
spriteAsh.x = _W * 0.5
spriteAsh.y = _H * 0.5
spriteAsh.xScale = 2
spriteAsh.yScale = 2
spriteAsh.linearDamping = 2
spriteAsh.myname = spriteAsh
spriteAsh.gravityScale = 0
local touchX, touchY
local touchScreen = function(e)
--print(e.phase, e.x, e.y)
if e.phase == "began" then
touchX = e.x
touchY = e.y
elseif e.phase == "moved" then
local difX = e.x - touchX
local difY = e.y - touchY
--spriteAsh:applyForce(difX *50, 0, spriteAsh.x, spriteAsh.y)
spriteAsh.x = spriteAsh.x + (e.x - touchX)
spriteAsh.y = spriteAsh.y + (e.y - touchY)
touchX = e.x
touchY = e.y
elseif e.phase == "ended" then
end
end
spriteAsh:addEventListener("touch", touchScreen)
local updateGame = function(e)
local seq
local velX, velY = spriteAsh:getLinearVelocity()
if math.abs (velX) >= math.abs (velY) then
--horizonal
if velX > 0 then
seq ="right_run"
else
seq = "left_run"
end
else
if velY > 0 then
seq = "down_run"
else
seq = "up_run"
end
end
if spriteAsh.sequence ~= seq then
spriteAsh:setSequence(seq)
spriteAsh:play()
end
end
Runtime:addEventListener("enterFrame", updateGame)
local function onScreenTouch1( event )
if event.phase == "began" then
character:applyForce( 250, -1500, character.x, character.y )
--end
end
return true
end
local function showFPS( event )
print( display.fps )
end
-- Called immediately after scene has moved onscreen:
function scene:enterScene( event )
print( "3: enterScene event" )
-- remove previous scene's view
storyboard.purgeScene( "scene2" )
-- update Lua memory text display
local showMem = function()
image:addEventListener( "touch", image )
text3.isVisible = true
--text2.text = text2.text .. collectgarbage("count")/0 .. " "
text2.x = display.contentWidth * 0.0
end
--memTimer = timer.performWithDelay( 0, showMem, 0 )
end
-- Called when scene is about to move offscreen:
function scene:exitScene()
storyboard.purgeScene( "scene" )
print( "3: exitScene event" )
-- remove touch listener for image
image:removeEventListener( "touch", image )
-- cancel timer
timer.cancel( memTimer ); memTimer = nil;
-- reset label text
text2.text = " "
end
-- Called prior to the removal of scene's "view" (display group)
function scene:destroyScene( event )
print( "3: destroyScene event" )
end
---------------------------------------------------------------------------------
-- END OF YOUR IMPLEMENTATION
---------------------------------------------------------------------------------
-- "createScene" event is dispatched if scene's view does not exist
scene:addEventListener( "createScene", scene )
-- "enterScene" event is dispatched whenever scene transition has finished
scene:addEventListener( "enterScene", scene )
-- "exitScene" event is dispatched before next scene's transition begins
scene:addEventListener( "exitScene", scene )
-- "destroyScene" event is dispatched before view is unloaded, which can be
-- automatically unloaded in low memory situations, or explicitly via a call to
-- storyboard.purgeScene() or storyboard.removeScene().
scene:addEventListener( "destroyScene", scene )
---------------------------------------------------------------------------------
return scene
答案 0 :(得分：1)
您的update功能存在问题。它有else卡在那里看起来不太好。
if math.abs (velX) >= math.abs (velY) then
--horizonal
if velX > 0 then
seq ="right_run"
else
seq = "left_run"
end
else -- <--- THIS SHOULD NOT BE HERE
if velY > 0 then
seq = "down_run"
else
seq = "up_run"
end
end
我也发现了一些带有一些功能的“气味”。在if语句中返回函数中的值时，请确保所有posible路径都返回一个值。例如：
-- THIS IS BAD:
local function restarto( self, event )
if event.phase == "began" then
print("restarted")
audio.play(sound_click)
physics.pause()
return true
end
end
尝试在逻辑的所有可能结果中返回一个值，如下所示：
local function restarto( self, event )
if event.phase == "began" then
print("restarted")
audio.play(sound_click)
physics.pause()
return true
else
return false
end
end