kylianvermeulen/arboreal

Features

• Drag and drop to reorder items within and across sections
• Self-sizing rows based on SwiftUI content
• Multi-selection drag support
• Collapsible sections with observable expansion state
• Live drop preview indicator with customizable theming
• Floating drag view that follows your finger
• Haptic feedback on drag, drop, hover, and error events
• Per-item and per-target validation callbacks
• Pure-function tree mutations (extract, insert, move)
• Zero external dependencies

Requirements

• iOS 18+
• Swift 6.2+
• Xcode 26+

Installation

Add Arboreal via Swift Package Manager:

https://github.com/kylianvermeulen/Arboreal.git

Or add it to your Package.swift:

dependencies: [
    .package(url: "https://github.com/kylianvermeulen/Arboreal.git", from: "0.3.0")
]

Quick Start

1. Define your content model

import Arboreal

struct Task: TreeNodeContent {
    let id: UUID
    let title: String
    var isContainer: Bool { false }
}

2. Build a tree

@State private var tree: [TreeNode<Task>] = [
    TreeNode(
        content: Task(id: UUID(), title: "Section"),
        children: [
            TreeNode(content: Task(id: UUID(), title: "Item A")),
            TreeNode(content: Task(id: UUID(), title: "Item B")),
        ]
    )
]

@State private var expansionState = ExpansionState<UUID>()

3. Use TreeDragDropView

TreeDragDropView(
    tree: tree,
    expansionState: expansionState
) { item, depth, isSelected, isExpanded in
    Text(item.title)
        .padding(.leading, CGFloat(depth) * 20)
}

Configuration

Customize behavior through TreeDragDropConfiguration:

var config = TreeDragDropConfiguration<Task>()
config.indentationWidth = 24
config.canDrag = { item in !item.isContainer }
config.onReorder = { newTree in save(newTree) }
config.dropPreviewTheme = DropPreviewTheme(
    fillColor: .blue.opacity(0.12),
    cornerRadius: 10,
    horizontalPadding: 16
)
config.floatingDragStyle = FloatingDragStyle(
    backgroundColor: .systemBackground,
    cornerRadius: 12,
    shadowOpacity: 0.3,
    liftScale: 1.05
)

TreeDragDropView(
    tree: tree,
    expansionState: expansionState,
    configuration: config
) { item, depth, isSelected, isExpanded in
    // ...
}

Key Types

| Type | Description | |------|-------------| | TreeNodeContent | Protocol your content model conforms to | | TreeNode | A tree node with content and children (max depth 1) | | TreeDragDropView | The main SwiftUI view | | TreeDragDropConfiguration | Layout, behavior, and callback settings | | ExpansionState | Observable state tracking expanded sections | | DropPreviewTheme | Drop indicator appearance | | FloatingDragStyle | Floating drag view appearance (corner radius, shadow, scale) | | HapticConfiguration | Haptic feedback toggles | | FlatTreeEntry | Flattened row representation used for layout | | DropTarget | Where a drop lands (.atIndex or .intoSection) | | DragPayload | What is being dragged (.singleItem, .multipleItems, .section) |

Tree Mutations

Pure functions on [TreeNode] for programmatic tree manipulation:

// Extract nodes by ID
let (remaining, extracted) = tree.extractingNodes(ids: selectedIDs)

// Insert at a target position
let updated = tree.insertingNodes(nodes, at: .atIndex(parentID: sectionID, index: 0))

// Move nodes to a new position
let moved = tree.movingNodes(ids: selectedIDs, to: .intoSection(sectionID))

// Check if a drop is valid
let allowed = tree.canDrop(draggedIDs: selectedIDs, onto: target)

// Flatten for layout
let entries = tree.flattened(expansionState: expansionState.expandedIDs)

Example

See Examples/Example/ for a working demo showing sections, tasks, expansion, and reordering.

License

MIT -- see LICENSE.

Package Metadata

Repository: kylianvermeulen/arboreal

Default branch: master

README: README.md