隐藏显示导航

(void)hideNavigationBar:(BOOL)hideNav {
if (hideNav) {
self.navigationController.navigationBar.translucent = YES;
[self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
[self.navigationController.navigationBar setShadowImage:[UIImage new]];
[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor],NSFontAttributeName:[UIFont boldSystemFontOfSize:17]}];

} else {
self.navigationController.navigationBar.translucent = NO;
self.navigationController.navigationBar.hidden = NO;
[self.navigationController.navigationBar setBackgroundImage:nil forBarMetrics:UIBarMetricsDefault];
[self.navigationController.navigationBar setShadowImage:nil];
[self.navigationController.navigationBar setTitleTextAttributes:@{NSFontAttributeName:TSTFont(17),NSForegroundColorAttributeName:HEXRGBCOLOR(0x4A4A4A)}];

}
}