我正在尝试更改 UINavigationControllerBar 中后退按钮上文本的字体颜色
[[UIBarButtonItem appearance] setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
给我这个错误:[_UIBarItemAppearance setTitleColor:forState:]: unrecognized selector sent to instance 0x69aeb70'
有什么帮助吗?谢谢!