CODEWITHSUNDEEP
androidandroid-jetpack-compose
Elye
Elye

Reputation: 60251

How can I start auto start an animation without onActive, and set the initial value for animatedFloatAsState

In the past (before alpha11), I can animate a value from 0 to 1 upon triggering the composable function as below, where I can set initialValue and also have onActive with aniumateTo.

val animatedProgress = animatedFloat(0f)
onActive {
    animatedProgress.animateTo(
        targetValue = 1f,
        anim = infiniteRepeatable(
            animation =
                tween(durationMillis = 2000, easing = LinearEasing),
        )
    )
}

val t = animatedProgress.value

However, now in alpha13, I cannot find a way to set initialValue, or animateTo. The onActive is also now deprecated.

I coded as below

    val floatAnimation = animateFloatAsState(
        targetValue = 1f,
        animationSpec = infiniteRepeatable(
            animation = tween(durationMillis = 2000, easing = LinearEasing),
        )
    )

How can I...

Upvotes: 3

Views: 2778

Answers (2)

Gabriele Mariotti
Gabriele Mariotti

Reputation: 364730

You can use the Animatable API and the LaunchedEffect composable. You don't need a boolean to start the animation.

Something like:

val animatedAlpha = remember { Animatable(0f) }

Box(
    Modifier
        .background(color = (Color.Blue.copy(alpha = animatedAlpha.value)))
        .size(100.dp,100.dp)

)

LaunchedEffect(animatedAlpha) {
    animatedAlpha.animateTo(1f,
        animationSpec = infiniteRepeatable(
            animation = tween(durationMillis = 2000, easing = LinearEasing)
        ))
}

enter image description here

Upvotes: 7

Elye
Elye

Reputation: 60251

Looks like I have to use a boolean to change the state and use LaunchEffect to start and change the state as below.

    var start by remember{ mutableStateOf(false) }

    val floatAnimation = animateFloatAsState(
        targetValue = if (start) 1f else 0f,
        animationSpec = infiniteRepeatable(
            animation = tween(durationMillis = 2000, easing = LinearEasing),
        )
    )
    LaunchedEffect(true) {
        start = true
    }

    val t = floatAnimation.value

Not sure if this is the best way to code around it.

Upvotes: 1

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