删除所有产生的硬币 [英] remove all spawned coins

问题描述

当游戏结束时，移除所有衍生硬币的最佳方法是什么?

What is the best way to remove all spawned coins when the game is over?

以下是产生硬币的代码:

Here is the code that spawns the coins:

 screenGroup = self.view
 coin = {}
 coinspawn = function()
 i = display.newSprite( imageSheet1, sequenceData1 )

    i.x = display.contentWidth
    i.y = math.random(0, display.contentHeight-50)
    i:play()
    i.collided = true
    i.name = "coin"
    physics.addBody(i, "dynamic", 
        {density=.1, bounce=0.1, friction=.2, shape= shape2 ,filter=playerCollisionFilter } 
    )   
    --player.gravityScale = 0.5
    coinIntro = transition.to(i,{time=2500, x=display.contentWidth - display.contentWidth -500  ,onComplete=jetReady , transition=easing.OutExpo } ) --
    coin[#coin+1] = i

end 
tmrcoin = timer.performWithDelay( 1000, coinspawn, 0 )

推荐答案

首先，您需要从显示中删除所有硬币.然后，您将清除coin表:

First you would remove all coins from the display. Then you would clear the coin table:

for i=1,#coin do 
    coin[i]:removeSelf()
end
coin = {}  -- forget all coins

假设coin表是您存储硬币的唯一其他位置，则可以完成此操作.

Assuming coin table is the only other place you store your coins, this will do it.

请注意，您不能在removeSelf之后的循环中使用coin[i]=nil:一旦表上有孔，则#运算符基本上将不可用.您也不能使用table.remove，因为每次我都会增加，所以您会错过项目(尝试，您会看到).对也存在相同的问题:遍历表时无法编辑表.但是，您可以这样做:

Note that you can't use coin[i]=nil in the loop after removeSelf: as soon as table has holes, the # operator is basically unusable. You can't use table.remove either, because i gets incremented every time, so you'll miss items (try, you'll see). Same issue with pairs: you can't edit a table while iterating through it. You could however do this:

local numCoins = #coin
for i=1,numCoins do 
    coin[i]:removeSelf()
    coin[i]=nil
end
-- now coin is {}

我能想到的是将N个项目设为n个而不是让gc用一个table = {}语句处理它的唯一原因是，如果您对钱币表有多个引用(我将重命名为钱币表，顺便说一句) (为清楚起见).

The only reason I can think of to nil N items instead of letting the gc take care of it with one table = {} statement is if you have more than one reference to your coin table (which I would rename to coins, BTW, for clarity).

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