iphone-从block中返回整数

Question

要从调用的block中返回整数：

-(NSInteger)globalRecord
{
    __block NSInteger globalRecord = 0;

    [GKLeaderboard loadLeaderboardsWithCompletionHandler:^(NSArray *leaderboards, NSError *error) {
        GKLeaderboard *globalTaps = nil;
        for (GKLeaderboard *lb in leaderboards) if ([lb.category isEqualToString:kGlobalLeaderboard]) globalTaps = lb;

        [globalTaps loadScoresWithCompletionHandler:^(NSArray *scores, NSError *error) {
            if ([scores count] != 0)
            {
                GKScore *topScore = [scores objectAtIndex:0];
                globalRecord = topScore.value;
                //42 here
            }

        }];
    }];

    //0 here

    return globalRecord;
}

从游戏中心的排行榜返回最高分，需求是只要接收到分数方法就返回给我，但是没返回成功。

比如在block中最高分是42，但是在block外值就是0。

请高手帮忙解答。

Answer 1

要获取globalRecord值应该使用一个回调。

-(void)globalRecord
{
    __block NSInteger globalRecord = 0;

    [GKLeaderboard loadLeaderboardsWithCompletionHandler:^(NSArray *leaderboards, NSError *error) {
        GKLeaderboard *globalTaps = nil;
        for (GKLeaderboard *lb in leaderboards) if ([lb.category isEqualToString:kGlobalLeaderboard]) globalTaps = lb;

        [globalTaps loadScoresWithCompletionHandler:^(NSArray *scores, NSError *error) {
            if ([scores count] != 0)
            {
                GKScore *topScore = [scores objectAtIndex:0];
                globalRecord = topScore.value;
                [self globalRecordRetrieved:globalRecord];
                //42 here
            }

        }];
    }];
}

- (void)globalRecordRetrieved:(NSInteger)record{
    NSLog(@"%d",record); //42 here
}