FloatAnimationSpec

Kotlin |Java

interface FloatAnimationSpec : AnimationSpec<Float>

androidx.compose.animation.core.FloatAnimationSpec

Known Direct Subclasses

FloatSpringSpec, FloatTweenSpec

FloatSpringSpec	FloatSpringSpec animation uses a spring animation to animate a Float value.
FloatTweenSpec	FloatTweenSpec animates a Float value from any start value to any end value using a provided easing function.

FloatAnimationSpec interface is similar to VectorizedAnimationSpec, except it deals exclusively with floats.

Like VectorizedAnimationSpec, FloatAnimationSpec is entirely stateless as well. It requires start/end values and start velocity to be passed in for the query of velocity and value of the animation. The FloatAnimationSpec itself stores only the animation configuration (such as the delay, duration and easing curve for FloatTweenSpec, or spring constants for FloatSpringSpec.

A FloatAnimationSpec can be converted to an VectorizedAnimationSpec using vectorize.

Summary

Public methods
abstract Long	`getDurationNanos(initialValue: Float, targetValue: Float, initialVelocity: Float)` Calculates the duration of an animation.
open Float	`getEndVelocity(initialValue: Float, targetValue: Float, initialVelocity: Float)` Calculates the end velocity of the animation with the provided start/end values, and start velocity.
abstract Float	`getValueFromNanos(playTimeNanos: Long, initialValue: Float, targetValue: Float, initialVelocity: Float)` Calculates the value of the animation at given the playtime, with the provided start/end values, and start velocity.
abstract Float	`getVelocityFromNanos(playTimeNanos: Long, initialValue: Float, targetValue: Float, initialVelocity: Float)` Calculates the velocity of the animation at given the playtime, with the provided start/end values, and start velocity.
open VectorizedFloatAnimationSpec<V>	`vectorize(converter: TwoWayConverter<Float, V>)` Create an VectorizedAnimationSpec that animates AnimationVector from a FloatAnimationSpec.

Public methods

getDurationNanos

abstract fun getDurationNanos(
    initialValue: Float, 
    targetValue: Float, 
    initialVelocity: Float
): Long

Calculates the duration of an animation. For duration-based animations, this will return the pre-defined duration. For physics-based animations, the duration will be estimated based on the physics configuration (such as spring stiffness, damping ratio, visibility threshold) as well as the initialValue, targetValue values, and initialVelocity.

Note: this may be a computation that is expensive - especially with spring based animations

Parameters
initialValue: Float	start value of the animation
targetValue: Float	end value of the animation
initialVelocity: Float	start velocity of the animation

getEndVelocity

open fun getEndVelocity(
    initialValue: Float, 
    targetValue: Float, 
    initialVelocity: Float
): Float

Calculates the end velocity of the animation with the provided start/end values, and start velocity. For duration-based animations, end velocity will be the velocity of the animation at the duration time. This is also the default assumption. However, for spring animations, the transient trailing velocity will be snapped to zero.

Parameters
initialValue: Float	start value of the animation
targetValue: Float	end value of the animation
initialVelocity: Float	start velocity of the animation

getValueFromNanos

abstract fun getValueFromNanos(
    playTimeNanos: Long, 
    initialValue: Float, 
    targetValue: Float, 
    initialVelocity: Float
): Float

Calculates the value of the animation at given the playtime, with the provided start/end values, and start velocity.

Parameters
playTimeNanos: Long	time since the start of the animation
initialValue: Float	start value of the animation
targetValue: Float	end value of the animation