调整tabBarItem 的title和image的位置

            //title上移

//            [vc.tabBarItem setTitlePositionAdjustment:UIOffsetMake(0,y)];

            //image上移

            viewController.tabBarItem.imageInsets=UIEdgeInsetsMake(-15,0,15,0);

            //这里y为0时即系统title位置，y小于0时title上移，image上移时x小于0，x与w为相反数，image位置才会显示在中间。

            文字设置富文本

UITabBarItem *item = [UITabBarItem appearanceWhenContainedIn:self, nil];

    NSMutableDictionary *dic = [NSMutableDictionary dictionary];

    dic[NSForegroundColorAttributeName] = [UIColor whiteColor];

    dic[NSFontAttributeName] = [UIFont systemFontOfSize:12];

    [item setTitleTextAttributes:dic forState:UIControlStateSelected];