Corona SDK的游戏网络（gameNetwork）和Game Center在iOS上无法正常工作。

我对这个问题感到很疯狂。按照如何使用gameNetwork的指南，却没有成功。这是我的代码：

main.lua

gameNetwork = require "gameNetwork"
loggedIntoGC = false

local function initCallback( event )
if event.data then
    loggedIntoGC = true
    - native.showAlert( "Success!", "User has logged into Game Center", { "OK" } )
else
    loggedIntoGC = false
    gameNetwork.request( "loadScores",
        { leaderboard={ category="com.mycompany.mygame.myrankingid",
        playerScope="Global", timeScope="AllTime", range={1,50} },
        listener=requestCallback } )

    - native.showAlert( "Fail", "User is not logged into Game Center", { "OK" } )
end
end

-- function to listen for system events
local function onSystemEvent( event )
if event.type == "applicationStart" then
    gameNetwork.init( "gamecenter", initCallback )
    return true
end
end
Runtime:addEventListener( "system", onSystemEvent )

然后只是为了测试：

if loggedIntoGC then
gameNetwork.request( "setHighScore",
  { localPlayerScore={ category="com.mycompany.mygame.myrankingid", value=t.text },
  listener=requestCallback } );
end

if loggedIntoGC then
gameNetwork.request( "loadScores",
  { leaderboard={ category="com.mycompany.mygame.myrankingid", playerScope="Global", timeScope="AllTime", range={1,50} },
  listener=requestCallback } );
end

if loggedIntoGC then
gameNetwork.show( "leaderboards",
  { leaderboard={ category="com.mycompany.mygame.myrankingid", timeScope="AllTime" } }     );
end

在设备上尝试示例没有任何作用，只是登录游戏中心用户...

请帮忙，谢谢！