Andrew Andrew - 25 days ago 13
iOS Question

How can I create a horizontal gradient background for my iOS nav bar?

I know how to set a navigation bar background color (with barTintColor), but now I am working on an iOS app that calls for a horizontal gradient (not the typical vertical gradient).

How can I create a navigation bar with a horizontal gradient background?

Answer

If you want to programmatically set the gradient of a given UINavigationBar I have a solution for you.

First setup a CAGradientLayer with your desired colors and locations.

CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.frame = navigationBar.bounds;
gradientLayer.colors = @[ (__bridge id)[UIColor greenColor].CGColor,
                          (__bridge id)[UIColor blueColor].CGColor ];
gradientLayer.startPoint = CGPointMake(0.0, 0.5);
gradientLayer.endPoint = CGPointMake(1.0, 0.5);

Then grab the UImage for that layer.

UIGraphicsBeginImageContext(gradientLayer.bounds.size);
[gradientLayer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *gradientImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Set the gradientImage as the backgroundImage for your UINavigationBar.

[navigationBar setBackgroundImage:gradientImage forBarMetrics:UIBarMetricsDefault];

Swift Solution:

[![// Setup the gradient
let gradientLayer = CAGradientLayer()
gradientLayer.frame = navigationBar.bounds
gradientLayer.colors = \[UIColor.greenColor(),UIColor.blueColor()\].map{$0.CGColor}
gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5)
gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5)

// Render the gradient to UIImage
UIGraphicsBeginImageContext(gradientLayer.bounds.size)
gradientLayer.renderInContext(UIGraphicsGetCurrentContext())
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

// Set the UIImage as background property
navigationBar.setBackgroundImage(image, forBarMetrics: UIBarMetrics.Default)

Result