2019-07-31

设置自定义self.navigationItem.rightBarButtonItem，iOS11以下这样写的写的按钮

[UIButton buttonWithType:UIButtonTypeCustom]不显示。

换成

[[UIButton alloc]initWithFrame:CGRectMake(0, 0, 50, 40)]

成功显示

参考：https://blog.csdn.net/ly410726/article/details/82426667