Expand & Collapse Animation for Accordion in Jetpack Compose

Accordian.kt

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.animation.AnimatedVisibility
import androidx.compose.animation.core.animateFloatAsState
import androidx.compose.animation.core.tween
import androidx.compose.animation.expandVertically
import androidx.compose.animation.fadeIn
import androidx.compose.animation.fadeOut
import androidx.compose.animation.shrinkVertically
import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.ArrowDropDown
import androidx.compose.material.icons.filled.Face
import androidx.compose.material3.Icon
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.draw.rotate
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.unit.dp


@Composable
fun Accordion(modifier: Modifier = Modifier) {
    var expanded by remember { mutableStateOf(false) }
    val arrowRotation by animateFloatAsState(
        targetValue = if (expanded) 180f else 0f,
        label = "accordion-arrow"
    )

    Surface(
        color = MaterialTheme.colorScheme.surfaceDim,
        modifier = modifier
            // clip the ripple effect and background
            .clip(RoundedCornerShape(12.dp))
            .clickable { expanded = !expanded }
    ) {
        Column {
            // accordion header
            Row(
                verticalAlignment = Alignment.CenterVertically,
                horizontalArrangement = Arrangement.spacedBy(12.dp),
                modifier = Modifier.padding(horizontal = 20.dp, vertical = 16.dp)
            ) {
                Icon(
                    imageVector = Icons.Filled.Face,
                    contentDescription = null
                )
                Text(
                    text = "Click here to expand",
                    style = MaterialTheme.typography.bodyLarge,
                    fontWeight = FontWeight.Bold,
                    // make sure the text fill the row
                    modifier = Modifier.weight(1f)
                )
                Icon(
                    imageVector = Icons.Filled.ArrowDropDown,
                    contentDescription = null,
                    // arrow rotation based on the expanded state
                    modifier = Modifier.rotate(arrowRotation)
                )
            }

            // accordion content
            AnimatedVisibility(
                visible = expanded,
                // animate expand vertically from the top when expanded + fade in
                enter = expandVertically(
                    expandFrom = Alignment.Top,
                    animationSpec = tween()
                ) + fadeIn(),
                // animate shrink vertically to the top when collapsed + fade out
                exit = shrinkVertically(
                    shrinkTowards = Alignment.Top,
                    animationSpec = tween()
                ) + fadeOut()
            ) {
                // expandable item
                Box(
                    modifier = Modifier
                        .padding(start = 8.dp, end = 8.dp, bottom = 8.dp)
                        .background(
                            color = MaterialTheme.colorScheme.surface,
                            shape = RoundedCornerShape(8.dp)
                        )
                ) {
                    Text(
                        text = "This is a bit long title so that you can get an idea how good this" +
                                "animation is",
                        style = MaterialTheme.typography.bodyMedium,
                        modifier = Modifier.padding(12.dp)
                    )
                }
            }
        }
    }
}