AnimationResult


AnimationResult contains information about an animation at the end of the animation. endState captures the value/velocity/frame time, etc of the animation at its last frame. It can be useful for starting another animation to continue the velocity from the previously interrupted animation. endReason describes why the animation ended, it could be either of the following:

import androidx.compose.animation.core.Animatable
import androidx.compose.animation.core.AnimationEndReason
import androidx.compose.animation.core.exponentialDecay
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.width
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Size

suspend fun CoroutineScope.animateBouncingOffBounds(
    animatable: Animatable<Offset, *>,
    flingVelocity: Offset,
    parentSize: Size
) {
    launch {
        var startVelocity = flingVelocity
        // Set bounds for the animation, so that when it reaches bounds it will stop
        // immediately. We can then inspect the returned `AnimationResult` and decide whether
        // we should start another animation.
        animatable.updateBounds(Offset(0f, 0f), Offset(parentSize.width, parentSize.height))
        do {
            val result = animatable.animateDecay(startVelocity, exponentialDecay())
            // Copy out the end velocity of the previous animation.
            startVelocity = result.endState.velocity

            // Negate the velocity for the dimension that hits the bounds, to create a
            // bouncing off the bounds effect.
            with(animatable) {
                if (value.x == upperBound?.x || value.x == lowerBound?.x) {
                    // x dimension hits bounds
                    startVelocity = startVelocity.copy(x = -startVelocity.x)
                }
                if (value.y == upperBound?.y || value.y == lowerBound?.y) {
                    // y dimension hits bounds
                    startVelocity = startVelocity.copy(y = -startVelocity.y)
                }
            }
            // Repeat the animation until the animation ends for reasons other than hitting
            // bounds, e.g. if `stop()` is called, or preempted by another animation.
        } while (result.endReason == AnimationEndReason.BoundReached)
    }
}

Summary

Public constructors

<T : Any?, V : AnimationVector> AnimationResult(
    endState: AnimationState<T, V>,
    endReason: AnimationEndReason
)
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Public functions

open String
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Public properties

AnimationEndReason

The reason why the animation has ended.

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AnimationState<T, V>

The state of the animation in its last frame before it's canceled or reset.

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Public constructors

AnimationResult

<T : Any?, V : AnimationVector> AnimationResult(
    endState: AnimationState<T, V>,
    endReason: AnimationEndReason
)

Public functions

toString

open fun toString(): String

Public properties

endReason

val endReasonAnimationEndReason

The reason why the animation has ended. Could be either of the following:

endState

val endStateAnimationState<T, V>

The state of the animation in its last frame before it's canceled or reset. This captures the animation value/velocity/frame time, etc at the point of interruption, or before the velocity is reset when the animation finishes successfully.