Delete lines with button not working

Hello,

I have a button that you press to make a line disappear, which you can see on the below code. It works fine the first time you swipe over the simulator and it produces a line, once you press the button the line vanishes. The only problem is that it only works once, if you try it again it has some sort of "bug" a line out of know where appears with no physic body. But the real problem is that you can't delete the line the second time and i can't figure out why. It is really weird, if you try it out you will see that the second time everything goes wrong. I just want to be able to draw a line constantly and press the button and the line deletes it self. Can anyone help me by giving advice or please an example of what is wrong. Thanks so much!

- All you need to have to test it out is one image for the UI button.
Thanks!

The code:

local ui = require("ui")
 
-- THE LINE IS A PHYSIC BODY, YOU CAN SEE IF YOU TURN ON DRAW MODE. THANKS.
 
 physics = require ("physics")
physics.start()
--physics.setDrawMode "hybrid"
 
-- Draw a line, swipe the simulator.
 
 
local i = 1
local tempLine
local rectangle_hit = {}
local prevX , prevY
local function runTouch(event)
if(event.phase=="began") then
if(tempLine==nil) then
tempLine=display.newLine(event.x, event.y, event.x, event.y)
 
 
prevX = event.x
prevY = event.y
end
elseif(event.phase=="moved") then
tempLine:append(event.x,event.y-2)
tempLine.width=tempLine.width+0.9
rectangle_hit[i] = display.newLine(prevX, prevY, event.x, event.y)
rectangle_hit[i]:setColor(105, 105, 105)
rectangle_hit[i].width = 5
tempLine.alpha = 0
 
 
-- Creates physic joints for line (Turn on draw mode to see the effects) 
 
local Width = rectangle_hit[i].width * 0.6
local Height = rectangle_hit[i].height * 0.2
 
-- Physic body for the line shape
 
local lineShape = {-Width,-Height,Width,-Height,Width,Height,-Width,Height}
 
physics.addBody(rectangle_hit[i], "static", { bounce = -1, density=0.3, friction=0.7, shape = lineShape})
prevX = event.x
prevY = event.y
i = i + 1
elseif(event.phase=="ended") then
tempLine.parent.remove(tempLine)
tempLine=nil
end
end
Runtime:addEventListener("touch", runTouch)
 
 
 
 
local button1Press = function( event )
-- Delete the line code:
 
for i = 1, #rectangle_hit, 1 do
              rectangle_hit[i]:removeSelf()
              rectangle_hit[i] = nil
 
end
end
 
-- UI button, change the image to yours.
 
local hi = ui.newButton{
        default = "drop.png",
        over = "drop.png",
        onPress = button1Press,
        emboss = true
}
 
hi.x = display.contentWidth/14
hi.y = display.contentHeight/12

every time you draw a line its handler is rectangle_hit itself. rectangle_hit is a table which actually stores many small lines which make the line you draw. so once you delete it in a loop it will delete the lines inside the table. so next time when u draw u use the same handle. so deleting is not that easy unless you have some means to identify the drawn lines separately.
look at the following code to see how you can create a handle for each line you draw.

local lines = {}
local myLines = {}      
local prevX,prevY
 
local function removeLine(myLine)
        for i=1,#myLine do
                        myLine[i]:removeSelf()
                        myLine[i] = nil
        end
end     
 
local i = 1
local function drawLine(e)
      if "began" == e.phase then
                        myLines[i] = {}
                        prevX = e.x
                    prevY = e.y
                elseif "moved" == e.phase then
                        if prevX then
                                        myLines[i][#myLines[i] + 1] = display.newLine(prevX,prevY,e.x,e.y)
                                        myLines[i][#myLines[i]].width = 3
                        end
                        prevX = e.x
                        prevY = e.y
                elseif "ended" == e.phase then
                                prevX = nil
                                prevY = nil
                i = i + 1
               --you can get to individual lines using this.
                                removeLine(myLines[#myLines-1])
                end
end
Runtime:addEventListener("touch",drawLine)

Hey,

Thanks a lot! I don't have that much time to look over it but it I scanned through it and sounds familiar to what i was thinking. Thanks for it! Another thing i was wondering about very similar to the deleting the lines is to just undo a bit of it, basically deleting very small bits of the line by pressing the button. Instead of removing each one, just deleting little bits of it until theres none left. Thanks a lot for the code that you gave me.

Michael

views:1530 update：2011/9/27 8:54:05


Label: corona android iphone ipad building error inmobi problem display screen View image tableView failed object physics touch button game lua config event listener