隱藏導航欄底部的線條
方法1 (單頁面設定)

[self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
 [self.navigationController.navigationBar setShadowImage:[UIImage new]];

如果不想影響其他頁面的導航透明度，viewWillDisappear將其設定為nil即可:

 [self.navigationController.navigationBar setBackgroundImage:nil
 
 forBarMetrics:UIBarMetricsDefault];
[self.navigationController.navigationBar setShadowImage:nil];

方法2(全域性設定)

[[UINavigationBar appearance] setBackgroundImage:[[UIImage alloc] init] forBarMetrics:UIBarMetricsDefault];

[[UINavigationBar appearance] setShadowImage:[[UIImage alloc] init]];

方法3

self.navigationController
 
.navigationBar.clipsToBounds = YES;

設定導航欄底部線條顏色的程式碼：

UINavigationBar *navigationBar = self.navigationController.navigationBar; 
[navigationBar setBackgroundImage:[[UIImage alloc] init] forBarPosition:UIBarPositionAny barMetrics:UIBarMetricsDefault]; //此處使底部線條顏色為紅色
[navigationBar setShadowImage:[UIImage imageWithColor:[UIColor redColor]]
 
];

@implementation UIImage (ColorImage)
+ (UIImage *)imageWithColor:(UIColor *)color{ 
CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f); 
UIGraphicsBeginImageContext(rect.size); 
CGContextRef context = UIGraphicsGetCurrentContext(); 
CGContextSetFillColorWithColor(context, [color CGColor]); 
CGContextFillRect(context, rect); 
UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); 
UIGraphicsEndImageContext(); return image;
}@end

修復navigationController側滑關閉失效的問題

self.navigationController.interactivePopGestureRecognizer.delegate = (id)self

隱藏返回按鈕後面的文字

[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)
                                                         forBarMetrics:UIBarMetricsDefault];