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Dynamic view annotations

Use Dynamic view annotations, Style, and the Viewport API to create a navigation experience.

Add AnnotationView class to your project

This example uses AnnotationView, a custom class defined in the Maps SDK for the iOS Examples App. To use this code snippet, you must also add the AnnotationView class to your project.

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DynamicViewAnnotationExample.swift
import UIKit
@_spi(Experimental) import MapboxMaps
import CoreLocation
import MapboxCoreMaps

private let simulatedCoordinate = CLLocationCoordinate2D(latitude: 37.6421, longitude: -122.4062)

final class ViewController: UIViewController {
private var mapView: MapView!
private var cancelables = Set<AnyCancelable>()

private var routes = [Route]() {
didSet {
oldValue.forEach { $0.remove() }
routes.forEach { route in
route.mapView = mapView
route.display()
route.onTap = { [unowned route, weak self] in
self?.select(route: route)
}
}
if let last = routes.last {
select(route: last, animated: false)
}
}
}

private lazy var modeButton = {
let button = UIButton(type: .system)
button.backgroundColor = .white
button.tintColor = .black
button.translatesAutoresizingMaskIntoConstraints = false
button.layer.cornerRadius = 20
button.layer.shadowColor = UIColor(red: 0.084, green: 0.176, blue: 0.283, alpha: 0.25).cgColor
button.layer.shadowOpacity = 1
button.layer.shadowRadius = 8
button.layer.shadowOffset = CGSize(width: 0, height: 2)
button.addTarget(self, action: #selector(changeMode), for: .touchUpInside)
NSLayoutConstraint.activate([
button.widthAnchor.constraint(equalToConstant: 200),
button.heightAnchor.constraint(equalToConstant: 40)
])
return button
}()

private var driveMode = false

override func viewDidLoad() {
super.viewDidLoad()

mapView = MapView(frame: view.bounds)
mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
view.addSubview(mapView)

updateModeButton()

mapView.location.override(
locationProvider: Signal(just: [
Location(
coordinate: simulatedCoordinate,
bearing: 168.8)
]),
headingProvider: Signal(just: Heading(direction: 180, accuracy: 0)))
mapView.location.options = LocationOptions(puckType: .puck2D(.init(topImage: UIImage(named: "dash-puck"))), puckBearing: .heading, puckBearingEnabled: true)

mapView.viewport.options.usesSafeAreaInsetsAsPadding = true

mapView.mapboxMap.onStyleLoaded.observeNext { [weak self] _ in
guard let self = self else { return }
loadRoutes()

}.store(in: &cancelables)

self.toolbarItems = [
UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil),
UIBarButtonItem(customView: modeButton),
UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
]

addParkingAnnotation(
coordinate: CLLocationCoordinate2D(latitude: 37.445, longitude: -122.1704),
text: "$6.99/hr")
addParkingAnnotation(
coordinate: CLLocationCoordinate2D(latitude: 37.4441, longitude: -122.1691),
text: "$5.99/hr")
}

private func loadRoutes() {
DispatchQueue.global(qos: .userInitiated).async {
let route1 = Route.load(name: "route-sf-1", time: "52 min")
let route2 = Route.load(name: "route-sf-2", time: "55 min")
route1.hint = ETAHint(text: "Avoid traffic", icon: "maneuver-straight")
route2.hint = ETAHint(text: "On highway", icon: "maneuver-turn-right")
DispatchQueue.main.async {
self.routes = [route1, route2]
}
}
}

private func select(route: Route, animated: Bool = true) {
// Move selected route layer on top of unselected route layers
let routeLayersIds = Set(routes.map(\.layerId))
let lastUnselected = mapView.mapboxMap.allLayerIdentifiers.last { info in
routeLayersIds.contains(info.id)
}
if let lastUnselected, lastUnselected.id != route.layerId {
try? mapView.mapboxMap.moveLayer(withId: route.layerId, to: .above(lastUnselected.id))
}

for r in routes {
// Update layer color
r.selected = r === route
}
if !driveMode {
updateViewport(animated: animated)
}
}

@objc private func changeMode() {
self.driveMode.toggle()
updateModeButton()

hideAnnotations(true)
updateViewport(animated: true) {
[weak self] in self?.hideAnnotations(false)
}
routes.forEach {
$0.updateProgress(with: driveMode ? simulatedCoordinate : nil)
}
}

private func updateModeButton() {
modeButton.setTitle("Mode: \(driveMode ? "Drive" : "Overview")", for: .normal)
}

private func hideAnnotations(_ hidden: Bool) {
routes.forEach {
$0.etaAnnotation?.visible = !hidden
}
}

private func updateViewport(animated: Bool, completion: (() -> Void)? = nil) {
var viewportState: ViewportState?
if driveMode {
viewportState = mapView.viewport.makeFollowPuckViewportState(options: .init(zoom: 17, bearing: .course, pitch: 49))
} else {
if let route = routes.first(where: \.selected), let geometry = route.feature.geometry {
let coordPadding = UIEdgeInsets(allEdges: 20)
let options = OverviewViewportStateOptions(geometry: geometry, geometryPadding: coordPadding)
viewportState = mapView.viewport.makeOverviewViewportState(options: options)
}
}

if let viewportState {
mapView.viewport.transition(
to: viewportState,
transition: animated ? mapView.viewport.makeDefaultViewportTransition() : mapView.viewport.makeImmediateViewportTransition()
) { _ in completion?() }
} else {
completion?()
}
}

private func addParkingAnnotation(coordinate: CLLocationCoordinate2D, text: String) {
let view = ParkingAnnotationView(text: text)

let annotation = ViewAnnotation(coordinate: coordinate, view: view)
annotation.allowOverlap = true
mapView.viewAnnotations.add(annotation)

view.onTap = { [unowned view, unowned annotation] in
annotation.selected.toggle()
view.selected = annotation.selected
annotation.setNeedsUpdateSize()
}
}

override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
navigationController?.setToolbarHidden(false, animated: false)
}
}

struct ETAHint {
var text: String
var icon: String
}

private final class Route {
let name: String
let time: String
let feature: Feature
var hint: ETAHint?
var selected: Bool = false {
didSet { updateSelected() }
}
var layerId: String { "route-\(name)" }
private(set) var etaAnnotation: ViewAnnotation?
private var etaView: ETAView?
private var displayed = false
private var tokens = Set<AnyCancelable>()

var onTap: (() -> Void)?
weak var mapView: MapView?

init(name: String, time: String, feature: Feature) {
self.name = name
self.time = time
self.feature = feature
}

func updateProgress(with coordinate: CLLocationCoordinate2D?) {
var progress = 0.0
if let coordinate,
case let .lineString(s) = feature.geometry,
let doneDistance = s.distance(to: coordinate),
let length = s.distance() {
progress = doneDistance / length + 0.0005
}

try? mapView?.mapboxMap.setLayerProperty(for: layerId, property: "line-trim-offset", value: [0, progress])
}

func display() {
guard !displayed, let mapView else { return }
displayed = true

func colorExpression(normal: String, selected: String) -> Exp {
Exp(.switchCase) {
Exp(.boolean) {
Exp(.featureState) { "selected" }
false
}
selected
normal
}
}

// Routes data source and layer
var source = GeoJSONSource(id: layerId)
source.data = .feature(feature)
source.lineMetrics = true
try! mapView.mapboxMap.addSource(source)

var routeLayer = LineLayer(id: layerId, source: layerId)
routeLayer.lineCap = .constant(.round)
routeLayer.lineJoin = .constant(.round)
routeLayer.lineWidth = .constant(10.0)
routeLayer.lineColor = .expression(colorExpression(normal: "#999999", selected: "#57A9FB"))
routeLayer.lineBorderWidth = .constant(2)
routeLayer.lineBorderColor = .expression(colorExpression(normal: "#666666", selected: "#327AC2"))
routeLayer.slot = .middle
try! mapView.mapboxMap.addLayer(routeLayer)

// Annotation
let etaView = ETAView(text: time)
self.etaView = etaView

let etaAnnotation = ViewAnnotation(layerId: layerId, view: etaView)
etaAnnotation.onAnchorChanged = { config in
etaView.anchor = config.anchor
}
etaAnnotation.variableAnchors = .all
etaView.onTap = { [weak self] in self?.onTap?() }

self.etaAnnotation = etaAnnotation
updateSelected()

mapView.viewAnnotations.add(etaAnnotation)
mapView.gestures.onLayerTap(layerId) { [weak self] feature, _ in
guard let self,
let onTap = onTap,
let identifier = feature.feature.identifier,
case let .string(id) = identifier,
id == self.name else { return false }
onTap()
return true
}.store(in: &tokens)
}

func remove() {
try? mapView?.mapboxMap.removeLayer(withId: self.layerId)
try? mapView?.mapboxMap.removeSource(withId: self.layerId)
self.etaAnnotation?.remove()
self.etaAnnotation = nil
self.etaView = nil
mapView = nil
onTap = nil
tokens.removeAll()
}

private func updateSelected() {
etaAnnotation?.selected = selected
etaView?.selected = selected
mapView?.mapboxMap.setFeatureState(sourceId: layerId, featureId: name, state: ["selected": selected]) {_ in}

etaView?.hint = selected ? nil : hint
etaAnnotation?.setNeedsUpdateSize()
}

static func load(name: String, time: String) -> Route {
let data = NSDataAsset(name: name)!.data
let feature = try! JSONDecoder().decode(Feature.self, from: data)
return .init(name: name, time: time, feature: feature)
}
}

private final class ParkingAnnotationView: UIView {
private let label = UILabel()
private let icon = UIImageView()
private let stack = UIStackView()
var text: String {
didSet { label.text = text }
}
var selected: Bool = false {
didSet { updateSelection() }
}

var onTap: (() -> Void)?

init(text: String) {
self.text = text

super.init(frame: .zero)
icon.image = UIImage(named: "parking-icon")
stack.axis = .horizontal
stack.spacing = 3
stack.addArrangedSubview(icon)
stack.addArrangedSubview(label)
stack.translatesAutoresizingMaskIntoConstraints = false
addSubview(stack)

NSLayoutConstraint.activate([
stack.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 3),
stack.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -12),
stack.topAnchor.constraint(equalTo: topAnchor, constant: 3),
stack.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -3),
icon.widthAnchor.constraint(equalToConstant: 24),
icon.heightAnchor.constraint(equalToConstant: 24)
])
layer.shadowColor = UIColor(red: 0.084, green: 0.176, blue: 0.283, alpha: 0.25).cgColor
layer.shadowOpacity = 1
layer.shadowRadius = 8
layer.shadowOffset = CGSize(width: 0, height: 2)
addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleTap)))
updateSelection()
updateText()
}

func updateText() {
label.attributedText = .labelText(text, size: 16, color: .black)
}

func updateSelection() {
backgroundColor = selected ? .systemBlue : .white
label.textColor = selected ? .white : .black
}

@objc private func handleTap() {
onTap?()
}

required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func layoutSubviews() {
super.layoutSubviews()
layer.cornerRadius = bounds.size.height / 2
}
}

final class ETAView: UIView {
private let label = UILabel()
private let iconView = UIImageView()
private var tail = UIView()
private let backgroundShape = CAShapeLayer()

var hint: ETAHint? {
didSet { update() }
}

var padding = UIEdgeInsets(allEdges: 10)
var tailSize = 8.0
var cornerRadius = 8.0
var selected: Bool = false {
didSet { update() }
}
var onTap: (() -> Void)?

var text: String {
didSet { update() }
}
var anchor: ViewAnnotationAnchor? {
didSet { setNeedsLayout() }
}

init(text: String) {
self.text = text
super.init(frame: .zero)
self.layer.addSublayer(backgroundShape)
backgroundShape.shadowRadius = 1.4
backgroundShape.shadowOffset = CGSize(width: 0, height: 0.7)
backgroundShape.shadowColor = UIColor.black.cgColor
backgroundShape.shadowOpacity = 0.3

iconView.contentMode = .scaleAspectFit
iconView.tintColor = UIColor(red: 0.04, green: 0.66, blue: 0.45, alpha: 1)
label.numberOfLines = 0
label.textAlignment = .left
addSubview(label)
addSubview(iconView)

update()

addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleTap)))
}

@objc private func handleTap() {
onTap?()
}

required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}

private var attributedText: NSAttributedString {
let text = NSMutableAttributedString(attributedString:
.labelText(text, size: 16, color: selected ? .white : .black, bold: true))
if let hint {
text.append(NSAttributedString(string: "\n"))
text.append(.labelText(hint.text, size: 12, color: .gray))
}
return text
}

private func update() {
self.backgroundShape.fillColor = selected ? UIColor.systemBlue.cgColor : UIColor.white.cgColor
self.label.attributedText = attributedText
self.iconView.image = hint.flatMap {
UIImage(named: $0.icon)?.withRenderingMode(.alwaysTemplate)
}
}

struct Layout {
var label: CGRect
var bubble: CGRect
var icon: CGRect
var size: CGSize

init(availableSize: CGSize, text: NSAttributedString, showIcon: Bool, tailSize: CGFloat, padding: UIEdgeInsets) {
let tailPadding = UIEdgeInsets(allEdges: tailSize)

var iconToText = 0.0
var iconFrame = CGRect.zero
if showIcon {
iconFrame = CGRect(padding: padding + tailPadding, size: CGSize(width: 24, height: 24))
iconToText = 5.0
}

let textPadding = padding + tailPadding + UIEdgeInsets(top: 0, left: iconFrame.width + iconToText, bottom: 0, right: 0)
let textAvailableSize = availableSize - textPadding
var textSize = text.boundingRect(
with: textAvailableSize,
options: .usesLineFragmentOrigin, context: nil
).size.roundedUp()
textSize.height = max(textSize.height, iconFrame.height)
iconFrame.size.height = textSize.height
icon = iconFrame
label = CGRect(padding: textPadding, size: textSize)
bubble = CGRect(padding: tailPadding, size: textSize + textPadding - tailPadding)
size = bubble.size + tailPadding
}
}

override func sizeThatFits(_ size: CGSize) -> CGSize {
Layout(availableSize: size, text: attributedText, showIcon: hint != nil, tailSize: tailSize, padding: padding).size
}

override func layoutSubviews() {
super.layoutSubviews()

let layout = Layout(availableSize: bounds.size, text: attributedText, showIcon: hint != nil, tailSize: tailSize, padding: padding)
label.frame = layout.label
iconView.frame = layout.icon

let calloutPath = UIBezierPath.calloutPath(size: bounds.size, tailSize: tailSize, cornerRadius: cornerRadius, anchor: anchor ?? .center)
backgroundShape.path = calloutPath.cgPath
backgroundShape.frame = bounds
}
}

func +(lhs: UIEdgeInsets, rhs: UIEdgeInsets) -> UIEdgeInsets {
return UIEdgeInsets(top: lhs.top + rhs.top, left: lhs.left + rhs.left, bottom: lhs.bottom + rhs.bottom, right: lhs.right + rhs.right)
}

func +(lhs: CGSize, rhs: UIEdgeInsets) -> CGSize {
return CGSize(width: lhs.width + rhs.left + rhs.right, height: lhs.height + rhs.top + rhs.bottom)
}

func -(lhs: CGSize, rhs: UIEdgeInsets) -> CGSize {
return lhs + -rhs
}

func +(lhs: CGSize, rhs: CGSize) -> CGSize {
return CGSize(width: lhs.width + rhs.width, height: lhs.height + rhs.height)
}

func +(lhs: CGPoint, rhs: CGPoint) -> CGPoint {
CGPoint(x: lhs.x + rhs.x, y: lhs.y + rhs.y)
}

func *(lhs: CGPoint, rhs: CGPoint) -> CGPoint {
CGPoint(x: lhs.x * rhs.x, y: lhs.y * rhs.y)
}

prefix func -(p: CGPoint) -> CGPoint {
p * CGPoint(x: -1, y: -1)
}

prefix func -(ins: UIEdgeInsets) -> UIEdgeInsets {
return UIEdgeInsets(top: -ins.top, left: -ins.left, bottom: -ins.bottom, right: -ins.right)
}

extension CGSize {
func roundedUp() -> CGSize {
CGSize(width: width.rounded(.up), height: height.rounded(.up))
}
}

extension CGRect {
init(padding: UIEdgeInsets, size: CGSize) {
self.init(origin: CGPoint(x: padding.left, y: padding.top), size: size)
}
}

extension UIEdgeInsets {
init(allEdges value: CGFloat) {
self.init(top: value, left: value, bottom: value, right: value)
}
}

extension NSAttributedString {
static func labelText(_ string: String, size: CGFloat, color: UIColor, bold: Bool = false) -> NSAttributedString {
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineHeightMultiple = 1.11
paragraphStyle.lineSpacing = 4
paragraphStyle.alignment = .left
let attributes = [
NSAttributedString.Key.paragraphStyle: paragraphStyle,
.font: bold ? UIFont.boldSystemFont(ofSize: size) : .systemFont(ofSize: size),
.foregroundColor: color,
]
return NSAttributedString(string: string, attributes: attributes)
}
}
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