[Corona SDK] 如何加入Apple Game Center 和 Android Google Play Game Service

不管是Apple的Game Center，還是Android的Google Play Game Service，
基本上都是利用gameNetwork的功能即可，
實作不難，考慮同時支援Apple和Google，
先將程式碼貼上再來講解：

local gameNetwork = require( "gameNetwork" )
local playerName
local playerId

local leaderboardsListId=
{
 ["HighestScore"]=
 {
  ["Description"] = "Highest Score",
  ["Identifier"] = "com.gmail.mycom.demo.Leaderboards.HighestScore"
 }
}

local achievementsListId = 
{
 ["FinishLevel1"]=
 {
  ["Description"] = "Finish Level 1",
  ["Identifier"] = "com.gmail.mycom.demo.Achievements.FinishLevel1"
 },
 ["FinishLevel2"]=
 {
  ["Description"] = "Finish Level 2",
  ["Identifier"] = "com.gmail.mycom.demo.Achievements.FinishLevel2"
 }
}

if(isAndroid) then
 leaderboardsListId=
 {
  ["HighestScore"]=
  {
   ["Description"] = "Highest Score",
   ["Identifier"] = "Cgkxxxxxxxx"
  }
 }

 achievementsListId = 
 {
  ["FinishLevel1"]=
  {
   ["Description"] = "Finish Level 1",
   ["Identifier"] = "Cgkxxxxxxx"
  },
  ["FinishLevel2"]=
  {
   ["Description"] = "Finish Level 2",
   ["Identifier"] = "Cgkxxxxxxxx"
  }
 }
end



function showLeaderboards( event )
 print("showLeaderboards()")
 if (playerId ~= nil) then
    if ( isAndroid ) then
       gameNetwork.show( "leaderboards" )
    else
       gameNetwork.show( "leaderboards", { leaderboard = {timeScope="AllTime"} } )
    end
 else
  gameNetworkSetup()
 end
    return true
end

local function postScoreSubmit( event )
   --whatever code you need following a score submission...
   return true
end

local function updateLeaderBoards(type, myScore)
 if (playerId == nil) then
  return
 end

 gameNetwork.request( "setHighScore",
 {
    localPlayerScore = { category=leaderboardsListId[type]["Identifier"], value=tonumber(myScore) },
    listener = postScoreSubmit
 } )
 print("gameNetwork.request( setHighScore) finished")
end

function showAchievements( event )
 print("showAchievements()")
 if (playerId ~= nil) then
    gameNetwork.show( "achievements" )
 else
  gameNetworkSetup()
 end
    return
end

local function achievementRequestCallback( event )
   
   return true
end

local function updateAchievement(type)
 if (playerId == nil) then
  return
 end
 gameNetwork.request( "unlockAchievement",
 {
    achievement = { identifier=achievementsListId[type]["Identifier"], percentComplete=100, showsCompletionBanner=true },
    listener = achievementRequestCallback
 } )
end

local function loadScoresCallback( event ) 
 if(event.data == nil) then
  print("event.data is nil")
  return
 end
 for i=1,25 do
  if(event.data[i] == nil) then
   break
  end
  print("event.data[",i,"].playerID:",event.data[i].playerID)
  print("event.data[",i,"].category:",event.data[i].category)
  if(event.data[i].playerID == playerId) then
   print("matched playID...........")
   break
  end
 end
end

local function loadLocalPlayerCallback( event ) 
 if(event.data == nil) then
  print("event.data is nil")
  return
 end

 playerId = event.data.playerID
 playerName = event.data.alias
 print("loadLocalPlayerCallback(),playerName:",playerName,",playerId:",playerId)
 if(playerId == nil) then
  return
 end
 myGameSettings.gameCerterHasEverLoggedIn = true
 saveData()   

 gameNetwork.request( "loadScores",
            {
                leaderboard =
                {
                    category = leaderboardsListId["HighestScore"]["Identifier"], 
                    playerScope = "Global",   -- Global, FriendsOnly
                    timeScope = "AllTime",    -- AllTime, Week, Today
                    --range = {1,5},
                    playerCentered = true,
                },
                listener = loadScoresCallback
            }) 
end

local function loadAchievementCallback( event )    
 if(event.data == nil) then
  print("event.data is nil")
  return
 end

 for i=1,#event.data do
  if(event.data[i] ~= nil) then
   print("event.data[",i,"].identifier:",event.data[i].identifier)
   print("event.data[",i,"].title:",event.data[i].title)
   print("event.data[",i,"].isCompleted:",event.data[i].isCompleted)
  end
 end 
end

local function gameNetworkLoginCallback( event )
 if(isAndroid==false) then
  if(event.data) then
   print("User has logged into iOS Game Center")
  else
   print("User has NOT logged into iOS Game Center")
   return 
  end
 end
 gameNetwork.request( "loadLocalPlayer", { listener=loadLocalPlayerCallback } )
 gameNetwork.request( "loadAchievements", { listener=loadAchievementCallback } )
 return true
end

local function gpgsInitCallback( event )
 if(event.data) then
  print("User has logged into Google App Play Center")
     gameNetwork.request( "login", { userInitiated=true, listener=gameNetworkLoginCallback } )
 else
  print("User has NOT logged into Google App Play Center")
 end
end

function gameNetworkSetup()
 if ( isAndroid ) then
  myGameSettings.gameCerterHasEverLoggedIn = false
  gameNetwork.init( "google", gpgsInitCallback )
 else
  gameNetwork.init( "gamecenter", gameNetworkLoginCallback )
 end
end
}

初始化
一般來說，我們可以在main.lua裡呼叫gameNetworkSetup()，
對於Android系統，在gpgsInitCallback()裡可以確認是否登錄成功
對於iOS系統，在gameNetworkLoginCallback()裡可以確認是否登錄成功，
至於後面的gameNetwork.request( "loadLocalPlayer", { listener=loadLocalPlayerCallback } )，
是用來確認目前登錄遊戲中心的使用者，有沒有呼叫它都可以，
gameNetwork.request( "loadAchievements", { listener=loadAchievementCallback } )則是用來回復使用者的紀錄， 例如使用曾經安裝過這個APP，移除它後又重新下載， 如果不想幫使用者回復紀錄，不執行也可以

顯示排行榜(leaderboard)
想要顯示排行榜，只要呼叫showLeaderboards()即可， 通常這個動作是在使用者按下某個按鈕時

顯示任務(achievement)
想要顯示排行榜，只要呼叫showAchievements()即可， 通常這個動作是在使用者按下某個按鈕時

更新排行榜 想要更新排行榜，只要呼叫updateLeaderBoards()即可， 通常這個動作是在使用者完成遊戲時

更新任務 想要更新排行榜，只要呼叫updateAchievement()即可， 通常這個動作是在使用者完成某個關卡時


以下是Apple的Game Center，和Android的Google Play Game Service稍有不同的地方

Apple Game Center

leaderboardsListId{}和achievementsListId{}裡的資料， 例如"com.gmail.mycom.demo.Leaderboards.HighestScore"， 這是使用者自己決定的編碼，然後在iTunes Connect裡設定即可， 不重覆就行

Google Play Game Service

leaderboardsListId{}和achievementsListId{}裡的資料，
例如"Cgkxxxxxxxx"， 這是使用者在play store publish的遊戲中心設定後系統給的編碼， 另外，對於Google Play Game Service， 我們還需要在build.settings增加:

android =
    {
        usesPermissions =
        {
            "android.permission.INTERNET",
            "android.permission.ACCESS_NETWORK_STATE",
            "com.android.vending.BILLING",
        },
        googlePlayGamesAppId = "123456789012" 
    },

usesPermissions無所謂，
googlePlayGamesAppId是在play store publish的遊戲中心連結應用程式後系統給的編碼