android - 电晕 : Check nil value before call onComplete event

Question

在调用 onComplete 之前，我需要检查“regalo”是否为 nil，因为有时会被 Collision 事件删除，当我调用 onComplete=removeRegalo 时它会返回错误 nil 值。

错误:尝试调用方法“removeSelf”(零值)

有什么想法吗？

    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