How to make completely transparent navigation bar in iOS 7

I want the UINavigationBar in my app to be completely transparent and flush with the viewcontroller directly under it. However, the only code I could find makes it translucent but not transparent. I know this can be done in iOS 7 because it is used in the notes app. My question is, what is the code they used to do it?

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最佳答案

From this answer

[self.navigationController.navigationBar setBackgroundImage:[UIImage new]
forBarMetrics:UIBarMetricsDefault];
self.navigationController.navigationBar.shadowImage = [UIImage new];
self.navigationController.navigationBar.translucent = YES;
self.navigationController.view.backgroundColor = [UIColor clearColor];
self.navigationController.navigationBar.backgroundColor = [UIColor clearColor];

Also, as suggested by Josh in the comments, to put the bar back to default:

[self.navigationController.navigationBar setBackgroundImage:nil
forBarMetrics:UIBarMetricsDefault];
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Alan forgot one line

self.navigationController.navigationBar.backgroundColor = [UIColor clearColor];

So I have:

[self.navigationController.navigationBar setTranslucent:YES];
self.navigationController.view.backgroundColor = [UIColor clearColor];
[self.navigationController.navigationBar setBackgroundImage:[[UIImage alloc] init] forBarMetrics:UIBarMetricsDefault];
self.navigationController.navigationBar.shadowImage = [[UIImage alloc] init];
self.navigationController.navigationBar.backgroundColor = [UIColor clearColor];
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Self contained solution as an Objective-C Category:

UINavigationController+TransparentNavigationController.h

@interface UINavigationController (TransparentNavigationController)
- (void)presentTransparentNavigationBar;
- (void)hideTransparentNavigationBar;
@end

UINavigationController+TransparentNavigationController.m

#import "UINavigationController+TransparentNavigationController.h"


@implementation UINavigationController (TransparentNavigationController)


- (void)presentTransparentNavigationBar
{
[self.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
[self.navigationBar setTranslucent:YES];
[self.navigationBar setShadowImage:[UIImage new]];
[self setNavigationBarHidden:NO animated:YES];
}


- (void)hideTransparentNavigationBar
{
[self setNavigationBarHidden:YES animated:NO];
[self.navigationBar setBackgroundImage:[[UINavigationBar appearance] backgroundImageForBarMetrics:UIBarMetricsDefault] forBarMetrics:UIBarMetricsDefault];
[self.navigationBar setTranslucent:[[UINavigationBar appearance] isTranslucent]];
[self.navigationBar setShadowImage:[[UINavigationBar appearance] shadowImage]];
}


@end

Now, you can import the category in your UIViewController and call the methods on your navigation controller - for example:

#import "UINavigationController+TransparentNavigationController.h"


- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self.navigationController presentTransparentNavigationBar];
}


- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
[self.navigationController hideTransparentNavigationBar];
}

And a similar solution in Swift:

import Foundation
import UIKit


extension UINavigationController {


public func presentTransparentNavigationBar() {
navigationBar.setBackgroundImage(UIImage(), forBarMetrics:UIBarMetrics.Default)
navigationBar.translucent = true
navigationBar.shadowImage = UIImage()
setNavigationBarHidden(false, animated:true)
}


public func hideTransparentNavigationBar() {
setNavigationBarHidden(true, animated:false)
navigationBar.setBackgroundImage(UINavigationBar.appearance().backgroundImageForBarMetrics(UIBarMetrics.Default), forBarMetrics:UIBarMetrics.Default)
navigationBar.translucent = UINavigationBar.appearance().translucent
navigationBar.shadowImage = UINavigationBar.appearance().shadowImage
}
}
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For Swift3 and Swift4

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

For Swift2.2

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

For Objective-C

[self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
self.navigationController.navigationBar.shadowImage = [UIImage new];
self.navigationController.navigationBar.translucent = YES;
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Use UINavigationBar+Addition pod, then simply call:

UINavigationBar *navigationBar = self.navigationController.navigationBar;
[navigationBar makeTransparent];
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[(UIView*)[self.navigationController.navigationBar.subviews objectAtIndex:0] setAlpha:0.0f];

That one line seemed to work perfectly for me

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@Zorayr's great answer revised to Swift 3 : 

import Foundation
import UIKit


extension UINavigationController {


public func presentTransparentNavigationBar() {
navigationBar.setBackgroundImage(UIImage(), for:.default)
navigationBar.isTranslucent = true
navigationBar.shadowImage = UIImage()
setNavigationBarHidden(false, animated:true)
}


public func hideTransparentNavigationBar() {
setNavigationBarHidden(true, animated:false)
navigationBar.setBackgroundImage(UINavigationBar.appearance().backgroundImage(for: UIBarMetrics.default), for:.default)
navigationBar.isTranslucent = UINavigationBar.appearance().isTranslucent
navigationBar.shadowImage = UINavigationBar.appearance().shadowImage
}
}
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Swift 4.2 and iOS 12

It turns out all you really need is the code below. It works perfectly when you put it into viewDidLoad().

// removes line at bottom of navigation bar
navigationController?.navigationBar.shadowImage = UIImage()


// makes navigation bar completely transparent
navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
navigationController?.navigationBar.isTranslucent = true

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