iOS 适配

一、状态栏
1.修改状态栏颜色
a在navigationitem上加个view
如果navigationitem，隐藏则失效
2.适配状态栏高度
([[UIApplication sharedApplication] statusBarFrame].size.height)

二、导航栏
(self.navigationController.navigationBar.frame.size.height)

三、安全区
20的高度
self.automaticallyAdjustsScrollViewInsets = NO;

四、刘海
[[UIApplication sharedApplication] delegate].window.safeAreaInsets.top;

五、底部
[[UIApplication sharedApplication] delegate].window.safeAreaInsets.bottom;