电晕：在调用onComplete事件之前检查nil值

Question

I need to check if "regalo" is nil or not, before call the onComplete, because sometimes is deleted by a Collision event and when I call onComplete=removeRegalo it return error nil value.

error: Attempt to call method 'removeSelf' (a nil value)

Any idea?

    local function removeRegalo(event)
        event:removeSelf()
        event = nil
    end
    local function tiraregalo()
        regalo = display.newImageRect("images/regalo.png", 30, 30)
        regalo.x = ship.x
        regalo.y = ship.y
        regalo:toFront()
        regalo.name = "regalo"
        physics.addBody( regalo, {isSensor = true } )
        grupoCasas:insert(regalo)
        local wind = 10 
        transition.to(regalo,{time=1500, y = screenH + 30, x = regalo.x + wind,rotation= math.random(-20,60), onComplete=removeRegalo})
    end
function onCollision( event )
    if(event.object1.name == "casa" and event.object2.name == "regalo") then
        display.remove( event.object2 )
    end
end

Answer 1

local function removeRegalo(event)
        if event == nil then return end
        event:removeSelf()
        -- event = nil Not really needed, but okay if you want it here.
    end

Answer 2

Would something like this work?

if regalo ~= nil then
  -- object exists so do some code
end

Hope it helps :)

Answer 3

Maybe this would do the job.

local function removeRegalo(event)
    -- Check if event:removeSelf exists
    if event:removeSelf then
        event:removeSelf()
        event = nil
    end
end

Answer 4

Here is the solution:

       local function removeRegalo(event)

            display.remove( event )
            event = nil
        end

event = nil --This is optional as @111WARLOCK111 said. Thanks!

Answer 5

   local function removeRegalo(event)
         local tempObject=event.target
         if tempObject  then         
              tempObject:removeSelf()
              tempObject = nil
        end
   end