需设置常态字体的颜色

    if(@available(iOS10.0, *)) {

        [[UITabBar appearance] setUnselectedItemTintColor:[UIColor xxxColor]];

    }

设施tabBar字体常态及选中状态的方法

    NSDictionary *normalAttribute = @{NSFontAttributeName: [UIFont systemFontOfSize:11],

                                      NSForegroundColorAttributeName:[UIColor xxxColor]};

    NSDictionary *selectedAttribute = @{NSFontAttributeName: [UIFont systemFontOfSize:11],

                                        NSForegroundColorAttributeName:[UIColor xxxColor]};

    // 设置tabbar字体颜色和大小

    UITabBarItem *tabBarItem = [UITabBarItem appearance]; // UI_APPEARANCE_SELECTOR

    [tabBarItemsetTitleTextAttributes:normalAttribute forState:UIControlStateNormal];

    [tabBarItemsetTitleTextAttributes:selectedAttribute forState:UIControlStateSelected];