无法在 Lua 中为事件侦听器指定表对象

问：

我正在学习 Solar2d 教程 （https://docs.coronalabs.com/guide/programming/index.html），我正在尝试将前几节课组合成一个气球爆破游戏。我想在表格中放置气球对象，点击会导致气球消失。我添加了事件侦听器，我在其中用气球定义其他所有内容。但是，点击不会执行任何操作。我的问题是：

1. 如何点击删除气球图像？
2. 我应该在哪里添加代码以从表中删除已点击的气球？游戏循环中有一个for循环吗？

提前致谢！

`-----------------------------------------------------------------------------------------
--
-- main.lua
--
-----------------------------------------------------------------------------------------

--prep the physics
local physics = require("physics")
physics.start()
physics.setGravity(0, -20)

--seed the random number generator
math.randomseed( os.time() )

--prep the graphic groups
local backGroup = display.newGroup()
local mainGroup = display.newGroup()
local uiGroup = display.newGroup()

--prep variables
local newBalloon
local tappedBalloon
local balloonTable = {}

--load background
local background = display.newImageRect(backGroup,  "pictures/mainGroup/background.png", 360, 570)
background.x = display.contentCenterX
background.y = display.contentCenterY

--load boundaries
local border = display.newImageRect(mainGroup, "pictures/mainGroup/border.png", 281, 35)
border.x = display.contentCenterX
border.y = display.contentHeight-440
physics.addBody( border, "static" )

local function popBalloon( event )
    local tappedBalloon = event.target
    if event.phase == "began" then
        display.remove(tappedBalloon)
        --removing balloon from table?
    end
end


--creating and storing balloons
local function createBalloon ()
    local newBalloon = display.newImageRect(mainGroup, "pictures/mainGroup/balloon2.png", 118, 118)
    if newBalloon then
        table.insert(balloonTable, newBalloon)
        physics.addBody( newBalloon, "dynamic", { radius=50, bounce=0.2 } )
        --newBalloon.isBullet = true
        newBalloon.alpha = 0.8
        newBalloon.myName = "balloon"
        newBalloon:addEventListener("tap", popBalloon)
    end
    
    local placement = math.random(3)

    if (placement == 1) then
        newBalloon.x = math.random( display.contentWidth )
        newBalloon.y = math.random( 250,500 )
    elseif ( placement == 2 ) then
        newBalloon.x = math.random( display.contentWidth )
        newBalloon.y = math.random( 250,500 )
    elseif ( placement == 3 ) then
        newBalloon.x = math.random( display.contentWidth )
        newBalloon.y = math.random( 250,500 )
    end
end

local function gameLoop()
    createBalloon()
end

gameLoopTimer = timer.performWithDelay( 500, gameLoop)`

我尝试将事件侦听器放在气球创建之外，但导致“nil value”错误代码。