当前VC 的角标

// 当前页面的消息

    self.navigationController.tabBarItem.badgeValue = [NSString stringWithFormat:@"%d", unReadCount];

逻辑增加，加个鸡腿

//
    NSString *aaa = [NSString stringWithFormat:@"%@", count];
    if ([aaa isEqualToString:@"0"]) {
        [self.navigationController.tabBarItem setBadgeValue:nil];// 隐藏角标
    } else if ([aaa intValue] > 99) {
        //
        self.navigationController.tabBarItem.badgeValue = [NSString stringWithFormat:@"99+"];
    } else {
        //
        self.navigationController.tabBarItem.badgeValue = [NSString stringWithFormat:@"%@", aaa];
    }