I'm having some troubles when I try to reload a scene.
In my program, users are able to draw a line with their finger (it's an iOS/Android app), and it works pretty good, but, when I try to reload the scene, the console returns
"Attempt to index field 'parent' (a nil value)"
at line 78
The code I've used to perform the "drawline" and the reload (replay in this case) features is
local lines = {}
local lineGroup = display.newGroup()
local prevX,prevY
local isDrawing = true
local i = 1
local function distanceBetween(x1, y1, x2, y2)
local dist_x = x2 - x1
local dist_y = y2 - y1
local distanceBetween = math.sqrt((dist_x*dist_x) + (dist_y*dist_y))
return distanceBetween
end
local function drawLine(e)
if(e.phase == "began") then
for i = #lines, 1, -1 do
if (lines[i]) then
if (lines[i].parent) then
lines[i].parent:remove(lines[i])
end
lines[i] = nil
end
end
lines = {}
line_number = 100
prevX = e.x
prevY = e.y
isDrawing = true
elseif(e.phase == "moved") then
local distance = distanceBetween(prevX, prevY, e.x, e.y)
if(isDrawing and distance < 100) then
if(lines[i]) then lineGroup:remove(i) end
lines[i] = display.newLine(prevX, prevY, e.x, e.y)
lines[i]:setColor(255, 255, 0)
lines[i].width = 3
lines[i].myName = "lines"
if(lines[i].y < 400) then
for i = #lines, 1, -1 do
if (lines[i]) then
if (lines[i].parent) then
lines[i].parent:remove(lines[i])
end
lines[i] = nil
end
end
end
local dist_x = e.x - prevX
local dist_y = e.y - prevY
physics.addBody(lines[i], "static",
{ density = 1, friction = 0.5, bounce =
-0.8, shape = {0, 0, dist_x, dist_y, 0, 0} } )
lineGroup:insert(lines[i])
end
elseif(e.phase == "ended") then
isDrawing = true
end
return lineGroup
end
Runtime:addEventListener("touch",drawLine)
where line 78 is:
lineGroup:insert(lines[i])
I restart my game using
local replayBTN = display.newImageRect("images/replay.png", 25, 25)
replayBTN.alpha = 1
replayBTN.x = _W/2
replayBTN.y = _H/2
localGroup:insert( replayBTN)
function replay(event)
director:changeScene("game")
return true
end
replayBTN:addEventListener("touch", replay)
How can I fix my problem? THANKS ;)
the moment you try to go to another scene don't reset all the values because you set it to nil so when you go back to your scene again you get an error and i see your using director class to change scene and go to the same scene have you try using storyboard i don't know if it will be much convenient to you because i'm thinking that your just trying to reset the value of the line
storyboard can recreate and reset all the value as you remove the scene and go to another scene. you can visit this link to compare director class and storyboard. http://www.coronalabs.com/blog/2012/04/17/director-to-storyboard-transition-guide/
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.