Custom animation timing in iOS Swift - UI Render Trace

Component - Custom animation timing

This UI component demonstrates how to create a custom animation timing in an iOS app using Swift. It animates a square view moving across the screen with a custom timing curve, making the animation feel smooth and natural.

Widget Tree

UIViewController
├── UIView (main view)
│   └── UIView (animated square)
└── UIButton (Start Animation)

The main screen is a UIViewController containing the main UIView. Inside it, there is a smaller UIView representing the square that will animate. A UIButton below triggers the animation when tapped.

Render Trace - 4 Steps

Step 1: UIViewController

Step 2: UIView (animated square)

Step 3: UIButton (Start Animation)

Step 4: UIViewPropertyAnimator

State Change - Re-render

Trigger:User taps the 'Start Animation' button

Before

Blue square is positioned near the left side of the screen

→

After

Blue square moves smoothly to the right side of the screen over 2 seconds with custom timing

Re-renders:The animated square UIView re-renders its position during the animation

UI Quiz - 3 Questions

What triggers the custom animation to start?

A Swiping the square

B Tapping the 'Start Animation' button

C Loading the view controller

D Double tapping the screen

Key Insight

Using UIViewPropertyAnimator with custom timing parameters allows developers to create smooth, natural animations that feel more engaging than default linear or ease-in/out animations. This enhances user experience by making UI interactions feel responsive and polished.