正确保留GKAchievement以便保存

Question

在成果报告期间遇到错误时，我将它添加到数组中，然后将数组保存到NSUserDefaults。但是，保存的信息始终为零。你如何正确保留数据？我尝试添加成就时调用retain，但这不会改变任何内容。我写数据，可以看到文件，但里面的对象是零。

- (void)reportAchievementIdentifier:(NSString*)identifier percentComplete:(float)percent 
{ 
    if (self.isGameCenterEnabled) { 
     GKAchievement *achievement = [[[GKAchievement alloc] initWithIdentifier:identifier] autorelease]; 
     if (achievement) 
     { 
      achievement.percentComplete = percent; 
      [achievement reportAchievementWithCompletionHandler:^(NSError *error) 
      { 
       if (error != nil) 
       { 
        if (![outstandingAchievementsToReport containsObject:achievement]){ 
         [outstandingAchievementsToReport addObject:achievement]; 
         [self saveUnsyncedAchievements]; 
        } 
       } 
      }]; 
     } 
    } 
} 

- (void)saveUnsyncedAchievements 
{ 
    NSString *docsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; 
    NSString *savePath = [docsPath stringByAppendingPathComponent:@"Achievements"]; 

    // Write to disk  
    if (![NSKeyedArchiver archiveRootObject:outstandingAchievementsToReport toFile:savePath]) {  
     NSLog(@" archiver write failed."); 
    } else { 
     NSLog(@" archiver write succeeded."); 
    } 
} 

- (void)loadUnsyncedAchievements 
{ 
    NSString *docsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; 
    NSString *savePath = [docsPath stringByAppendingPathComponent:@"Achievements"]; 

    // Read from disk 
    outstandingAchievementsToReport = [NSKeyedUnarchiver unarchiveObjectWithFile:savePath]; 

    NSLog(@"outstandingAchievementsToReport count = %d", [outstandingAchievementsToReport count]); 
} 

- (void) reportOutstandingAchievements { 
    NSLog(@"Report all outstanding achievements."); 
    for (GKAchievement *achievement in outstandingAchievementsToReport) { 
     [self reportAchievementIdentifier:achievement.identifier percentComplete:achievement.percentComplete]; 
    } 
} 

Answer 1

即使数组在init中被分配，它也会出现reportAchievement方法，认为它是nil。测试没有解决问题。

- (void)reportAchievementIdentifier:(NSString*)identifier percentComplete:(float)percent 
{ 
    if (self.isGameCenterEnabled) { 
     GKAchievement *achievement = [[[GKAchievement alloc] initWithIdentifier:identifier] autorelease]; 
     if (achievement) 
     { 
      achievement.percentComplete = percent; 
      [achievement reportAchievementWithCompletionHandler:^(NSError *error) 
      { 
       if (error != nil) 
       { 
        if (nil == outstandingAchievementsToReport) 
         outstandingAchievementsToReport = [[NSMutableArray alloc] init]; 

        if (![outstandingAchievementsToReport containsObject:achievement]){ 
         [outstandingAchievementsToReport addObject:achievement]; 
        } 
       } 
      }]; 
     } 
    } 
} 

Answer 2

阅读苹果的这个官方纪录片作为类引用 http://developer.apple.com/library/ios/#documentation/GameKit/Reference/GKAchievement_Ref/Reference/Reference.html

 OR 

这里是GitHub-非常有用源的TypeOneError http://www.typeoneerror.com/articles/post/game-center-achievement-notification

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