iOS - 集成game center （leader board）
最近又一次用到game center里面的leader board。其实这个事情很简单，只是很容易忘记。所以就打算写下来。
iTunes Connect上创建app，然后启用game center
创建app就省略了，等创建成功后，不需要提交。我们就可以设置game center了。
首先点击新建的app，找到Game Center，如图
点击进入具体的game center设置，可以添加一些项目。很是简单，基本上都有提示，需要注意的是排行榜id，得搞个独立的，不要重复。这个id在代码里面需要使用。
就这么简单的搞几下，game center就启用了。
在代码中引入game center
在xcode的工程里面打开game center，
直接打开就行，感觉ios开发越来越傻瓜了，呵呵。
接下来就是具体的代码实现了。
代码实现
首先在合适的地方添加如下代码：通常是
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
double ver = [[UIDevice currentDevice].systemVersion doubleValue];
if (ver < 6.0) {
[[GKLocalPlayer localPlayer] authenticateWithCompletionHandler:^(NSError *error) {
}];
}
else
{
[[GKLocalPlayer localPlayer] setAuthenticateHandler:(^(UIViewController* viewcontroller, NSError *error) {
})];
}
NSNotificationCenter* ns = [NSNotificationCenter defaultCenter];
[ns addObserver:self selector:@selector(authenticationChanged) name:GKPlayerAuthenticationDidChangeNotificationName object:nil];
- (void) authenticationChanged
{
if ([GKLocalPlayer localPlayer].isAuthenticated) {
NSLog(@"authenticationChanged, authenticated");
}
else
{
NSLog(@"authenticationChanged, Not authenticated");
}
}接下来就是提交和显示leader board了。具体的说明苹果的官网上说的很清楚。我这里在网上找到一个封装的源代码，自己稍微修改了一下。具体代码看最后面（附）。这里主要介绍使用流程。先增加一个属性。
@property (readwrite, retain) PlayerModel * player;- (void) updatePlayer
{
if (!self.player || ![self.player.currentPlayerID isEqualToString:[GKLocalPlayer localPlayer].playerID]) {
[self.player release];
self.player = [[PlayerModel alloc] init];
}
[[self player] loadStoredScores];
}- (void) authenticationChanged
{
if ([GKLocalPlayer localPlayer].isAuthenticated) {
NSLog(@"authenticationChanged, authenticated");
[self updatePlayer];
}
else
{
NSLog(@"authenticationChanged, Not authenticated");
}
}它支持多用户，如果是第一次登陆game center，那么就创建一个对象，如果是换了个用户登录，那么就把之前的释放，然后创建一个新的对象。然后调用loadStoredScore.
loadStoredScore会从本地文件里面读取需要传送的分数，并且往game center服务器传。
上面这段代码的意思就是app起来后，authenticationChanged被调用了，如果是登录的状态，那么就会创建一个PlayerModel对象。如果有需要上传的数据，那么就读取并且尝试上传。
其实这是个保护措施，后面会讲到为什么需要这么做。
接下来就看看如果在游戏中即时上传数据。
首先增加一个函数，这个函数就是往服务器发送数据。self.player submitScore，这个函数会在后面看到。有了这个函数，我们在游戏或者应用的某个地方可以调用往服务器发送数据了。LEADERBOARD_DISTANCE的值就是上面connect里面创建的那个排行榜id。
- (void) storeScore:(NSNumber *)distance
{
if (!self.player)
return;
int64_t score64 = [distance longLongValue];
GKScore * submitScore = [[GKScore alloc] initWithCategory:LEADERBOARD_DISTANCE];
[submitScore setValue:score64];
[self.player submitScore:submitScore];
[submitScore release];
}ok,就这么简单。现在就大概讲讲PlayerModel的原理。因为我们在提交的时候往往会因为网络原因而失败，特别在中国。所以，PlayerModel里面就提交了一个机制，如果提交失败，就把要提交的数据保存到本地文件，在合适的时候再尝试提交。
- (void)submitScore:(GKScore *)score
{
if ([GKLocalPlayer localPlayer].authenticated) {
if (!score.value) {
// Unable to validate data.
return;
}
// Store the scores if there is an error.
[score reportScoreWithCompletionHandler:^(NSError *error){
if (!error || (![error code] && ![error domain])) {
// Score submitted correctly. Resubmit others
[self resubmitStoredScores];
} else {
// Store score for next authentication.
[self storeScore:score];
}
}];
}
}现在就看看如果在app里面显示leader board。看下面的代码gameCenterAuthenticationComplete是我内部使用的一个bool，用来标记用户是否登录了game center。调用一下这个代码，就会显示iOS的game center。
- (void) showGameCenter
{
if (gameCenterAuthenticationComplete) {
GKLeaderboardViewController * leaderboardViewController = [[GKLeaderboardViewController alloc] init];
[leaderboardViewController setCategory:LEADERBOARD_DISTANCE];
[leaderboardViewController setLeaderboardDelegate:_viewController];
[self.viewController presentModalViewController:leaderboardViewController animated:YES];
[leaderboardViewController release];
}
}header file：
#import
#import
@interface PlayerModel : NSObject {
NSLock *writeLock;
}
@property (readonly, nonatomic) NSString* currentPlayerID;
@property (readonly, nonatomic) NSString *storedScoresFilename;
@property (readonly, nonatomic) NSMutableArray * storedScores;
// Store score for submission at a later time.
- (void)storeScore:(GKScore *)score ;
// Submit stored scores and remove from stored scores array.
- (void)resubmitStoredScores;
// Save store on disk.
- (void)writeStoredScore;
// Load stored scores from disk.
- (void)loadStoredScores;
// Try to submit score, store on failure.
- (void)submitScore:(GKScore *)score ;
@end
m file：
#import "PlayerModel.h"
@implementation PlayerModel
@synthesize storedScores,
currentPlayerID,
storedScoresFilename;
- (id)init
{
self = [super init];
if (self) {
currentPlayerID = [[NSString stringWithFormat:@"%@", [GKLocalPlayer localPlayer].playerID] retain];
NSString* path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
storedScoresFilename = [[NSString alloc] initWithFormat:@"%@/%@.storedScores.plist",path, currentPlayerID];
writeLock = [[NSLock alloc] init];
}
return self;
}
- (void)dealloc
{
[storedScores release];
[writeLock release];
[storedScoresFilename release];
[currentPlayerID release];
[super dealloc];
}
// Attempt to resubmit the scores.
- (void)resubmitStoredScores
{
if (storedScores) {
// Keeping an index prevents new entries to be added when the network is down
int index = (int)[storedScores count] - 1;
while( index >= 0 ) {
GKScore * score = [storedScores objectAtIndex:index];
[self submitScore:score];
[storedScores removeObjectAtIndex:index];
index--;
}
[self writeStoredScore];
}
}
// Load stored scores from disk.
- (void)loadStoredScores
{
NSArray * unarchivedObj = [NSKeyedUnarchiver unarchiveObjectWithFile:storedScoresFilename];
if (unarchivedObj) {
storedScores = [[NSMutableArray alloc] initWithArray:unarchivedObj];
[self resubmitStoredScores];
} else {
storedScores = [[NSMutableArray alloc] init];
}
}
// Save stored scores to file.
- (void)writeStoredScore
{
[writeLock lock];
NSData * archivedScore = [NSKeyedArchiver archivedDataWithRootObject:storedScores];
NSError * error;
[archivedScore writeToFile:storedScoresFilename options:NSDataWritingFileProtectionNone error:&error];
if (error) {
// Error saving file, handle accordingly
}
[writeLock unlock];
}
// Store score for submission at a later time.
- (void)storeScore:(GKScore *)score
{
[storedScores addObject:score];
[self writeStoredScore];
}
// Attempt to submit a score. On an error store it for a later time.
- (void)submitScore:(GKScore *)score
{
if ([GKLocalPlayer localPlayer].authenticated) {
if (!score.value) {
// Unable to validate data.
return;
}
// Store the scores if there is an error.
[score reportScoreWithCompletionHandler:^(NSError *error){
if (!error || (![error code] && ![error domain])) {
// Score submitted correctly. Resubmit others
[self resubmitStoredScores];
} else {
// Store score for next authentication.
[self storeScore:score];
}
}];
}
}
@end