Adding Physics with UIKit Dynamics | Application Development in iOS 7

Adding gravity

Open FoodDetailViewController.m and add the following instance variables to the view controller:

UIDynamicAnimator* animator;
UIGravityBehavior* gravity;

Scroll to viewDidLoad and add the following code to the bottom of the method:

animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];
gravity = [[UIGravityBehavior alloc] initWithItems:@[self.foodImageView]];
    [animator addBehavior:gravity];

Run the application, open the My Foods view, select a food item from the table view, and watch what happens. The food image should start to accelerate towards the bottom of the screen until it eventually falls off the screen, as shown in the following set of screenshots:

Let's go over the code, specifically the two new classes that were just introduced, UIDynamicAnimator and UIGravityBehavior.

Tech Concepts

Programming languages

Tech Tools

Unlimited access to the largest independent learning library in tech of over 8,000 expert-authored tech books and videos.

Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.

50+ new titles added per month and exclusive early access to books as they are being written.

Application Development in iOS 7

By : Kyle Begeman

Application Development in iOS 7

By: Kyle Begeman

Overview of this book

Adding gravity

Application Development in iOS 7

By : Kyle Begeman

Application Development in iOS 7

By: Kyle Begeman

Overview of this book

Adding gravity

Confirmation

Buy this book with your credits?

Submit Your Feedback

Create a Free Account To Continue Reading

Sign in to activate your 7-day free access