Simple tree hierarchy rendering with Jetpack Compose

TreeRenderer.kt

package com.example.myapplication

import androidx.compose.animation.AnimatedVisibility
import androidx.compose.animation.ExperimentalAnimationApi
import androidx.compose.foundation.Box
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.size
import androidx.compose.runtime.Composable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp
import androidx.ui.tooling.preview.Preview

@ExperimentalAnimationApi
@Composable
fun Node(
    modifier: Modifier = Modifier,
    nodeModel: NodeModel
) {
    Column(
        horizontalGravity = Alignment.CenterHorizontally
    ) {
        val isChildrenShown = remember { mutableStateOf(true) }

        NodeBox(
            modifier = modifier.clickable(onClick = {
                isChildrenShown.value = !isChildrenShown.value
            }),
            isExpanded = isChildrenShown.value
        )

        Spacer(modifier = Modifier.size(8.dp))

        AnimatedVisibility(visible = isChildrenShown.value) {
            Row(
                modifier = modifier,
                horizontalArrangement = Arrangement.Center
            ) {
                nodeModel.children.forEachIndexed { index, model ->
                    Node(nodeModel = model)
                    if (index != nodeModel.children.size - 1) {
                        Spacer(modifier = Modifier.size(4.dp))
                    }
                }
            }
        }
    }
}

@Composable
fun NodeBox(modifier: Modifier = Modifier, isExpanded: Boolean) {
    Box(
        modifier = modifier.size(8.dp),
        backgroundColor = if (isExpanded) Color.Green else Color.Blue
    )
}


@ExperimentalAnimationApi
@Preview
@Composable
fun TreePreview() {
    Node(
        nodeModel = rootModel()
    )
}

data class NodeModel(val children: List<NodeModel> = emptyList())

private fun rootModel(): NodeModel {
    return NodeModel(
        listOf(
            NodeModel(
                listOf(
                    NodeModel(
                        listOf(
                            NodeModel(
                                listOf(
                                    NodeModel(
                                        listOf(
                                            NodeModel(
                                                listOf(
                                                    NodeModel(
                                                        listOf(
                                                            NodeModel(),
                                                            NodeModel(),
                                                            NodeModel(),
                                                        )
                                                    ),
                                                    NodeModel(
                                                        listOf(
                                                            NodeModel(),
                                                            NodeModel(),
                                                            NodeModel(),
                                                        )
                                                    ),
                                                )
                                            ),
                                            NodeModel(
                                                listOf(
                                                    NodeModel(),
                                                    NodeModel(),
                                                    NodeModel(),
                                                )
                                            ),
                                        )
                                    ),
                                    NodeModel(
                                        listOf(
                                            NodeModel(),
                                            NodeModel(),
                                            NodeModel(),
                                        )
                                    ),
                                )
                            ),
                            NodeModel(
                                listOf(
                                    NodeModel(),
                                    NodeModel(),
                                    NodeModel(),
                                )
                            ),
                        )
                    ),
                    NodeModel(
                        listOf(
                            NodeModel(),
                            NodeModel(),
                            NodeModel(),
                        )
                    ),
                    NodeModel(
                        listOf(
                            NodeModel(),
                            NodeModel(),
                            NodeModel(),
                        )
                    )
                )
            ),

            NodeModel(
                listOf(
                    NodeModel(
                        listOf(
                            NodeModel(
                                listOf(
                                    NodeModel(
                                        listOf(
                                            NodeModel(
                                                listOf(
                                                    NodeModel(
                                                        listOf(
                                                            NodeModel(),
                                                            NodeModel(),
                                                            NodeModel(),
                                                        )
                                                    ),
                                                    NodeModel(
                                                        listOf(
                                                            NodeModel(),
                                                            NodeModel(),
                                                            NodeModel(),
                                                        )
                                                    ),
                                                )
                                            ),
                                            NodeModel(
                                                listOf(
                                                    NodeModel(),
                                                    NodeModel(),
                                                    NodeModel(),
                                                )
                                            ),
                                        )
                                    ),
                                    NodeModel(
                                        listOf(
                                            NodeModel(),
                                            NodeModel(),
                                            NodeModel(),
                                        )
                                    ),
                                )
                            ),
                            NodeModel(
                                listOf(
                                    NodeModel(),
                                    NodeModel(),
                                    NodeModel(),
                                )
                            ),
                        )
                    ),
                    NodeModel(
                        listOf(
                            NodeModel(),
                            NodeModel(),
                            NodeModel(),
                        )
                    ),
                    NodeModel(
                        listOf(
                            NodeModel(),
                            NodeModel(),
                            NodeModel(),
                        )
                    )
                )
            ),
        )
    )
}

This is simple and looks nice, thanks for sharing!