iOS开发 GCD

1. GCD信号量

//创建信号量
dispatch_semaphore_t semaphore = dispatch_semaphore_create(1);
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(queue, ^{
    // 等待信号量
    dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
    // 发起网络请求
    [BadgeCountModel HomeBadgeCountBlock:^(NSDictionary *data) {
        NSNumber *num = data[@"num"];
        if (num.integerValue > 0 ) {
            weakSelf.rightBt.isShowBadge = YES;
        } else {
            weakSelf.rightBt.isShowBadge = NO;
        }
        // 发送信号量
        dispatch_semaphore_signal(semaphore);
    } andError:^(NSError *error) {
        dispatch_semaphore_signal(semaphore);
    }]; 
});

dispatch_async(queue, ^{
dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
    // 发起网络请求
    [BadgeCountModel HomeDetailBadgeCountBlock:^(NSArray *data) {
        if (!weakSelf.badgeDict) {
            weakSelf.badgeDict = [NSMutableDictionary dictionary];
        }
        [weakSelf.badgeDict removeAllObjects];
        NSMutableArray *badgeArray = [NSMutableArray array];
        for (NSDictionary *dict in data) {
            BadgeCountModel *model = [[BadgeCountModel alloc] init];
            model.code = [NSString stringWithFormat:@"%@",dict[@"key"]];
            model.value = [NSString stringWithFormat:@"%@",dict[@"value"]];
            [badgeArray addObject:model];
            NSIndexPath *path = [self getIndexPathWithCode:model.code];
            if (!path) {
            continue;
            }
            [weakSelf.badgeDict setObject:model.value forKey:path];
        }
        [weakSelf.collectionView reloadData];
        [[GLMenuManager shareInstance] setRedPointArray:badgeArray];
        dispatch_semaphore_signal(semaphore);
    } andError:^(NSError *error) {
        dispatch_semaphore_signal(semaphore);
    }];
});

2. GCD单例

+ (instancetype)shared {
    static Share *shared = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        shared = [[Share alloc]init];
    });
    return shared;
}