tabBar颜色改动

//未点击的颜色

[[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                                       [UIColor whiteColor], NSForegroundColorAttributeName,
                                                       nil] forState:UIControlStateNormal];

//点击的颜色

    UIColor *titleHighlightedColor = [UIColor yellowColor];
    [[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                                       titleHighlightedColor, NSForegroundColorAttributeName,
                                                       nil] forState:UIControlStateSelected];