How to draw a transparent UIToolbar or UINavigationBar in iOS7
Solution 1:
Swift 3 (iOS 10)
Transparent UIToolbar
self.toolbar.setBackgroundImage(UIImage(),
forToolbarPosition: .any,
barMetrics: .default)
self.toolbar.setShadowImage(UIImage(), forToolbarPosition: .any)
Transparent UINavigationBar
self.navigationBar.setBackgroundImage(UIImage(), for: .default)
self.navigationBar.shadowImage = UIImage()
self.navigationBar.isTranslucent = true
Swift < 3
Transparent UIToolbar
self.toolbar.setBackgroundImage(UIImage(),
forToolbarPosition: UIBarPosition.Any,
barMetrics: UIBarMetrics.Default)
self.toolbar.setShadowImage(UIImage(),
forToolbarPosition: UIBarPosition.Any)
Transparent UINavigationBar
self.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: UIBarMetrics.Default)
self.navigationBar.shadowImage = UIImage()
self.navigationBar.translucent = true
Objective-C
Transparent UIToolbar
[self.toolbar setBackgroundImage:[UIImage new]
forToolbarPosition:UIBarPositionAny
barMetrics:UIBarMetricsDefault];
[self.toolbar setShadowImage:[UIImage new]
forToolbarPosition:UIBarPositionAny];
Transparent UINavigationBar
[self.navigationBar setBackgroundImage:[UIImage new]
forBarMetrics:UIBarMetricsDefault];
self.navigationBar.shadowImage = [UIImage new];
self.navigationBar.translucent = YES;
Discussion
Setting translucent
to YES
on the navigation bar does the trick, due to a behavior discussed in the UINavigationBar
documentation. I'll report here the relevant fragment:
If you set this property to
YES
on a navigation bar with an opaque custom background image, the navigation bar will apply a system opacity less than 1.0 to the image.
Final result
Solution 2:
If you want to do it through the entire app you should use the UIAppearance proxy (iOS5+):
UINavigationBar *navigationBarAppearance = [UINavigationBar appearance];
navigationBarAppearance.backgroundColor = [UIColor clearColor];
[navigationBarAppearance setBackgroundImage:[[UIImage alloc] init] forBarMetrics:UIBarMetricsDefault];
navigationBarAppearance.shadowImage = [[UIImage alloc] init];
Docs: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIAppearance_Protocol/Reference/Reference.html
Article: http://nshipster.com/uiappearance/
Solution 3:
Try:
[navBar setBackgroundImage:[UIImage alloc] forBarMetrics:UIBarMetricsDefault];