Ios UIBarButtonim关闭模式ViewController后更改字体

我在AppDelegate中设置了默认外观：

NSDictionary *barButtonAppearanceDict = @{NSFontAttributeName : FONT_MAIN_NAVIGATION};
[[UIBarButtonItem appearance] setTitleTextAttributes:barButtonAppearanceDict forState:UIControlStateNormal];
[[UIBarButtonItem appearance] setTitleTextAttributes:barButtonAppearanceDict forState:UIControlStateApplication];
[[UIBarButtonItem appearance] setTitleTextAttributes:barButtonAppearanceDict forState:UIControlStateDisabled];
[[UIBarButtonItem appearance] setTitleTextAttributes:barButtonAppearanceDict forState:UIControlStateHighlighted];
[[UIBarButtonItem appearance] setTitleTextAttributes:barButtonAppearanceDict forState:UIControlStateReserved];
[[UIBarButtonItem appearance] setTitleTextAttributes:barButtonAppearanceDict forState:UIControlStateSelected];

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我打开第一个ViewController导航栏项目为OK=FONT\u MAIN\u导航，然后我打开模态ViewController，当关闭模态ViewController第一个ViewController时，将导航栏项目更改为默认值。为什么要把它改回默认值，因为我没有在其他地方设置它。如何防止和修复它。

您的ViewController的ViewDidDisplay或ViewWillDisplay函数中有什么？我注释掉了ViewDidDisplay和ViewWillDisplay中的所有内容，但仍然使用UIBarButtonim更改字体。我尝试了一个修复-创建按钮再次在视图中出现，它创建了正确的字体。