iOS tabBarItem 改变文字大小颜色

// tab背景色
self.tabBarController.tabBar.backgroundColor = [UIColor whiteColor];
//不透明
self.tabBarController.tabBar.translucent = NO;
// tab选中的字体颜色 和字号
[[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor redColor],NSForegroundColorAttributeName,[UIFont systemFontOfSize:12.0f],NSFontAttributeName,nil] forState:UIControlStateNormal];// tab未选中的字体颜色 和字号
[[UITabBarItem appearance]setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor whiteColor],NSForegroundColorAttributeName,[UIFont systemFontOfSize:12.0f],NSFontAttributeName,nil] forState:UIControlStateSelected];