c# / Xamarin解决方案

NavigationController.NavigationBar.SetBackgroundImage(new UIImage(), UIBarMetrics.Default);
NavigationController.NavigationBar.ShadowImage = new UIImage();
NavigationController.NavigationBar.Translucent = true;

试试下面这段代码:

self.navigationController.navigationBar.translucent = YES;

下面的代码扩展了为这个线程选择的顶部答案，以消除底部边框并设置文本颜色:

The last two coded lines of this code set transparency. I borrowed that code from this thread and it worked perfectly! The "clipsToBounds" property was code I found which got rid of the bottom border line with OR without transparency set (so if you decide to go with a solid white/black/etc. background instead, there will still be no border line). The "tintColor" line (2nd coded line) set my back button to a light grey I kept barTintColor as a backup. I don't know why transparency would not work, but if it doesn't, I want my bg white as I used to have it let navigationBarAppearace = UINavigationBar.appearance() navigationBarAppearace.tintColor = UIColor.lightGray navigationBarAppearace.barTintColor = UIColor.white navigationBarAppearace.clipsToBounds = true navigationBarAppearace.isTranslucent = true navigationBarAppearace.setBackgroundImage(UIImage(), for: .default) navigationBarAppearace.shadowImage = UIImage()

如果你使用最新的测试版iOS 13.4和Xcode 11.4进行构建，那么接受的答案将不再适用。 我找到了另一种方法，也许这只是测试版软件中的一个bug，但我把它写下来了，以防万一

(5)迅速

import UIKit

class TransparentNavBar :UINavigationBar {
    override func awakeFromNib() {
        super.awakeFromNib()
        self.setBackgroundImage(UIImage(), for: .default)
        self.shadowImage = UIImage()
        self.isTranslucent = true
        self.backgroundColor = .clear
        if #available(iOS 13.0, *) {
            self.standardAppearance.backgroundColor = .clear
            self.standardAppearance.backgroundEffect = .none
            self.standardAppearance.shadowColor = .clear
        }
    }
}

对于任何想在Swift 2.x中这样做的人:

self.navigationController?.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: .Default)
self.navigationController?.navigationBar.shadowImage = UIImage()
self.navigationController?.navigationBar.translucent = true

或Swift 3.x:

self.navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
self.navigationController?.navigationBar.shadowImage = UIImage()
self.navigationController?.navigationBar.isTranslucent = true

这似乎很有效:

@implementation UINavigationBar (custom)
- (void)drawRect:(CGRect)rect {}
@end

navigationController.navigationBar.backgroundColor = [UIColor clearColor];