# keyframeAnimator(initialValue:trigger:content:keyframes:) Plays the given keyframes when the given trigger value changes, updating the view using the modifiers you apply in `body`. ``` nonisolated func keyframeAnimator(initialValue: Value, trigger: some Equatable, @ContentBuilder content: @escaping @Sendable (PlaceholderContentView, Value) -> some View, @KeyframesBuilder keyframes: @escaping (Value) -> some Keyframes) -> some View ``` ## Parameters `initialValue` The initial value that the keyframes will animate from. `trigger` A value to observe for changes. `content` A content builder closure that takes two parameters. The first parameter is a proxy value representing the modified view. The second parameter is the interpolated value generated by the keyframes. `keyframes` Keyframes defining how the value changes over time. The current value of the animator is the single argument, which is equal to `initialValue` when the view first appears, then is equal to the end value of the previous keyframe animation on subsequent calls. ## Discussion Note that the `content` closure will be updated on every frame while animating, so avoid performing any expensive operations directly within `content`. If the trigger value changes while animating, the `keyframes` closure will be called with the current interpolated value, and the keyframes that you return define a new animation that replaces the old one. The previous velocity will be preserved, so cubic or spring keyframes will maintain continuity from the previous animation if they do not specify a custom initial velocity. When a keyframe animation finishes, the animator will remain at the end value, which becomes the initial value for the next animation. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)