destroying joints

I'm facing a problem with removing joints.

When clicking on the background, a ball collides with a rectangle shape. On collision a distance joint is created. Then when the ball is tapped the joint should be destroyed, but when I use myJoint:removeSelf() I get an error. I tried almost everything but I can't figure it out.

I also was trying the same with a weld joint, but i get even more errors when i try to destroy it.

would greatly appreciate any help with correcting the following code

thanks

-- remove status bar
display.setStatusBar( display.HiddenStatusBar )
 
-- start physics
local physics = require( "physics" )
physics.start()
physics.setDrawMode( "hybrid" )
local ball
local other
local myJoint
 
local bg = display.newRect( 0, 0, display.contentWidth, display.contentHeight )
          bg:setFillColor( 0, 0, 0 )
        
-- creates a wall to bounce things off
local function addWall( x, y, width, height )
        local wall = display.newRect( 0, 0, width, height )
        wall.myName = "wall"
        wall:setFillColor( 255, 255, 255 )
        physics.addBody( wall, "static", { friction=1, bounce=.5, density=1 } )
        wall.x, wall.y = x, y
end
 
-- create the walls round the edge of the screen
addWall( display.contentWidth/2, 0, display.contentWidth, 10 )
addWall( display.contentWidth, display.contentHeight/2, 10, display.contentHeight )
addWall( display.contentWidth/2, display.contentHeight, display.contentWidth, 10 )
addWall( 0, display.contentHeight/2, 10, display.contentHeight )
 
local rect = display.newRect(display.contentWidth * 0.4, (display.contentHeight * 0.5) - 30, 64, 30 )
          physics.addBody( rect, "static", { friction=0.5 } )     
          rect:setFillColor( 188, 143, 4 )
          rect.myName = "rect"
 
                ball = display.newCircle( display.contentWidth * 0.5, (display.contentHeight * 0.9) - 30, 20 )
                ball.myName = "ball"
                ball:setFillColor( math.random(150, 255), math.random(150, 255), math.random(150, 255) )
                physics.addBody( ball, "dynamic", { friction=1, bounce=.7, density=1, radius=radius } )
                
                
local function weld()
                myJoint = physics.newJoint( "distance", ball, other, ball.x, ball.y, other.x, other.y )
                end     
 
local function collide (event)
                other = event.other
                ball:removeEventListener("collision", collide)
                timer.performWithDelay( 0, weld, 1 )
                end
 
 
local function bounce (event)
            ball:setLinearVelocity( 0, -450)
                ball:addEventListener("collision", collide)
                end
 
 
                local function removeJoint (event)
                        myJoint:removeSelf()
                end
 
                local function removeJ (event)
                        local phase = event.phase
 
                        if "began" == phase then
                        removeJoint()
                        end
                        
                        return true                     
                                end
 
                                ball:addEventListener("touch", removeJ)
                                bg:addEventListener("touch", bounce)

The code seems to work ok for me. The joint gets removed the first time I click on the ball. The second I click on it I do get an error about removeSelf() being a nil value, but that's because the joint was removed on the prior touch. For instance, I don't get any error after adding a nil check.

local function removeJoint (event)
    if myJoint ~= nil then
        myJoint:removeSelf()
        myJoint = nil
    end
end

views:1374 update：2011/10/6 9:28:12


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