EnterExitTransitionConfig

Artifact: androidx.compose.animation:animation

Cmn
```
class EnterExitTransitionConfig
```

Configurations for all transitions within an EnterTransition or ExitTransition.

This class exposes the internal parameters for all transition effects that have been combined into the transition. If an effect is not present in the transition, its corresponding configuration property will be null.

import androidx.compose.animation.EnterTransition
import androidx.compose.animation.ExitTransition
import androidx.compose.animation.core.animateFloat
import androidx.compose.animation.core.tween
import androidx.compose.animation.core.updateTransition
import androidx.compose.animation.fadeIn
import androidx.compose.animation.fadeOut
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.size
import androidx.compose.material.Button
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.drawWithContent
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Rect
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.ColorFilter
import androidx.compose.ui.graphics.ColorMatrix
import androidx.compose.ui.graphics.Paint
import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
import androidx.compose.ui.graphics.graphicsLayer
import androidx.compose.ui.unit.dp

var visible by remember { mutableStateOf(true) }

// A custom transition container that uses enter/exit transition configurations to build custom
// transition behavior.
@Composable
fun customTransitionBox(
    enter: EnterTransition,
    exit: ExitTransition,
    content: @Composable () -> Unit,
) {
    val transition = updateTransition(visible, label = "CustomTransitionBox")

    // Use the fade config to animate alpha
    val fadeConfig = if (transition.targetState) enter.config.fade else exit.config.fade

    val alpha by
        transition.animateFloat(
            transitionSpec = { fadeConfig?.animationSpec ?: tween() },
            label = "alpha",
        ) { state ->
            if (state) 1f else fadeConfig?.alpha ?: 0f
        }

    Box(
        modifier =
            Modifier.graphicsLayer { this.alpha = alpha }
                .drawWithContent {
                    // Apply custom saturation fade using alpha
                    val matrix = ColorMatrix().apply { setToSaturation(alpha) }
                    drawIntoCanvas { canvas ->
                        val paint =
                            Paint().apply { colorFilter = ColorFilter.colorMatrix(matrix) }
                        canvas.saveLayer(Rect(Offset.Zero, size), paint)
                        drawContent()
                        canvas.restore()
                    }
                }
    ) {
        content()
    }
}

Column {
    Button(onClick = { visible = !visible }) { Text("Toggle visibility") }

    customTransitionBox(
        fadeIn(animationSpec = tween(durationMillis = 1000), initialAlpha = 0f),
        fadeOut(animationSpec = tween(durationMillis = 1000), targetAlpha = 0f),
    ) {
        Box(Modifier.size(200.dp).background(Color.Blue))
    }
}

Summary

Public functions
`open operator Boolean`	`equals(other: Any?)`	Cmn
`open Int`	`hashCode()`	Cmn
`open String`	`toString()`	Cmn

Public properties
`ChangeSizeConfig?`	`changeSize` The size change effect configuration, or `null` if size change is not defined.	Cmn
`FadeConfig?`	`fade` The fade effect configuration, or `null` if fade is not defined.	Cmn
`ScaleConfig?`	`scale` The scale effect configuration, or `null` if scale is not defined.	Cmn
`SlideConfig?`	`slide` The slide effect configuration, or `null` if slide is not defined.	Cmn
`VeilConfig?`	`veil` The veil effect configuration, or `null` if veil is not defined.	Cmn

Public functions

equals

Cmn

open operator fun equals(other: Any?): Boolean

hashCode

Cmn

open fun hashCode(): Int

toString

Cmn

open fun toString(): String

Public properties

changeSize

Cmn

Added in 1.13.0-alpha01

val changeSize: ChangeSizeConfig?

The size change effect configuration, or null if size change is not defined.

fade

Cmn

Added in 1.13.0-alpha01

val fade: FadeConfig?

The fade effect configuration, or null if fade is not defined.

scale

Cmn

Added in 1.13.0-alpha01

val scale: ScaleConfig?

The scale effect configuration, or null if scale is not defined.

slide

Cmn

Added in 1.13.0-alpha01

val slide: SlideConfig?

The slide effect configuration, or null if slide is not defined.

veil

Cmn

Added in 1.13.0-alpha01

val veil: VeilConfig?

The veil effect configuration, or null if veil is not defined.