This recipe will demonstrate how to use CAGradientLayer to add gradients to a custom UIView.
- You should have basic knowledge of UIView and Core Animation, specifically CALayer.
- Basic knowledge of autolayout usage in interface builder.
Setting Up A Sample Application
- Create a new Single View Application in Xcode named GradientViewDemo. Make sure to check Use Automatic Reference Counting and uncheck Use Storyboards. Our demo app will also be iPhone only to keep things simple, but go ahead make a universal app if you like (everything we will do is applicable on both iPhone and iPad),
- Create a new UIView subclass named NSCBGradientView. We added the NSCB class prefix, because this may be a valuable component to reuse in future projects and the prefix will help avoid name clashing.
- Next, we need to add QuartzCore to the target. Do so by selecting the project file in the source list on the left, then ensure the GradientViewDemo target has been selected, select the Build Phases tab from the tab bar at the top, expand the Link Binary with Libraries, and finally click the + button in the lower left corner. Search for QuartzCore, and then add it to the target.