iOS 11 使用两种方法替换(Method Swizzling)去掉导航栏返回按钮的文字

方法一：设置BarButtonItem的文本样式为透明颜色，代码如下： [[UIBarButtonItem appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor clearColor]} forState:UIControlStateNormal]; [[UIBarButtonItem appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor clearColor]} forState:UICo