tei/MapLibreParticleLab
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Add iOS example data from API with dynamic styling (#2535)

Browse Source
This commit is contained in:
Bart Louwers
2024-06-22 00:41:26 +02:00
committed by GitHub
parent 459fd2844f
commit 880fd2ed91
8 changed files with 465 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
platform/ios/MapLibre.docc/LineStyleLayerExampleUIKit.md
View File

@@ -71,8 +71,7 @@ class LineStyleLayerExampleUIKit: UIViewController, MLNMapViewDelegate {
layer.lineColor = NSExpression(forConstantValue: UIColor(red: 59 / 255, green: 178 / 255, blue: 208 / 255, alpha: 1))
// Use `NSExpression` to smoothly adjust the line width from 2pt to 20pt between zoom levels 14 and 18. The `interpolationBase` parameter allows the values to interpolate along an exponential curve.
layer.lineWidth = NSExpression(format: "mgl_interpolate:withCurveType:parameters:stops:($zoomLevel, 'linear', nil, %@)",
[14: 2, 18: 20])
layer.lineWidth = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [14: 2, 18: 20]))
// We can also add a second layer that will draw a stroke around the original line.
let casingLayer = MLNLineStyleLayer(identifier: "polyline-case", source: source)
@@ -84,7 +83,7 @@ class LineStyleLayerExampleUIKit: UIViewController, MLNMapViewDelegate {
// Stroke color slightly darker than the line color.
casingLayer.lineColor = NSExpression(forConstantValue: UIColor(red: 41 / 255, green: 145 / 255, blue: 171 / 255, alpha: 1))
// Use `NSExpression` to gradually increase the stroke width between zoom levels 14 and 18.
casingLayer.lineWidth = NSExpression(format: "mgl_interpolate:withCurveType:parameters:stops:($zoomLevel, 'linear', nil, %@)", [14: 1, 18: 4])
casingLayer.lineWidth = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [14: 1, 18: 4]))
// Just for fun, let’s add another copy of the line with a dash pattern.
let dashedLayer = MLNLineStyleLayer(identifier: "polyline-dash", source: source)

1
platform/ios/MapLibre.docc/MapLibre.md
View File

@@ -18,6 +18,7 @@ Powerful, free and open-source mapping toolkit with full control over data sourc
- <doc:LocationPrivacyExample>
- <doc:BlockingGesturesExample>
- <doc:LineStyleLayerExampleUIKit>
- <doc:WebAPIDataExampleUIKit>
## Topics

224
platform/ios/MapLibre.docc/WebAPIDataExampleUIKit.md Normal file
View File

@@ -0,0 +1,224 @@
# Showing data from an API (UIKit)
Showing data from an API with custom styling and interaction
This example loads lighthouses in the United States from [WikiData](http://tinyurl.com/zrl2jc4). It adds points to the map and applies dynamic styling to these points. When zooming in the dots become larger circles with a custom icon and the name of the lighthouse shown next to it. When tapping a callout is shown with the name of the lighthouse that was tapped on.
<!-- include-example(WebAPIDataExampleUIKit) -->
```swift
class WebAPIDataExampleUIKit: UIViewController, MLNMapViewDelegate {
var mapView: MLNMapView!
override func viewDidLoad() {
super.viewDidLoad()
mapView = MLNMapView(frame: view.bounds)
mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
mapView.setCenter(CLLocationCoordinate2D(latitude: 37.090240, longitude: -95.712891), zoomLevel: 2, animated: false)
mapView.delegate = self
mapView.attributionButton.isHidden = true
view.addSubview(mapView)
// Add a single tap gesture recognizer. This gesture requires the built-in MLNMapView tap gestures (such as those for zoom and annotation selection) to fail.
let singleTap = UITapGestureRecognizer(target: self, action: #selector(handleMapTap(sender:)))
for recognizer in mapView.gestureRecognizers! where recognizer is UITapGestureRecognizer {
singleTap.require(toFail: recognizer)
}
mapView.addGestureRecognizer(singleTap)
}
func mapView(_: MLNMapView, didFinishLoading _: MLNStyle) {
fetchPoints { [weak self] features in
self?.addItemsToMap(features: features)
}
}
func addItemsToMap(features: [MLNPointFeature]) {
// MLNMapView.style is optional, so you must guard against it not being set.
guard let style = mapView.style else { return }
// You can add custom UIImages to the map style.
// These can be referenced by an MLNSymbolStyleLayer’s iconImage property.
style.setImage(UIImage(named: "lighthouse")!, forName: "lighthouse")
// Add the features to the map as a shape source.
let source = MLNShapeSource(identifier: "us-lighthouses", features: features, options: nil)
style.addSource(source)
let lighthouseColor = UIColor(red: 0.08, green: 0.44, blue: 0.96, alpha: 1.0)
// Use MLNCircleStyleLayer to represent the points with simple circles.
// In this case, we can use style functions to gradually change properties between zoom level 2 and 7: the circle opacity from 50% to 100% and the circle radius from 2pt to 3pt.
let circles = MLNCircleStyleLayer(identifier: "lighthouse-circles", source: source)
circles.circleColor = NSExpression(forConstantValue: lighthouseColor)
// The circles should increase in opacity from 0.5 to 1 based on zoom level.
circles.circleOpacity = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [2: 0.5, 7: 1]))
circles.circleRadius = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [2: 2, 7: 3]))
// Use MLNSymbolStyleLayer for more complex styling of points including custom icons and text rendering.
let symbols = MLNSymbolStyleLayer(identifier: "lighthouse-symbols", source: source)
symbols.iconImageName = NSExpression(forConstantValue: "lighthouse")
symbols.iconColor = NSExpression(forConstantValue: lighthouseColor)
symbols.iconScale = NSExpression(forConstantValue: 0.5)
symbols.iconHaloColor = NSExpression(forConstantValue: UIColor.white.withAlphaComponent(0.5))
symbols.iconHaloWidth = NSExpression(forConstantValue: 1)
symbols.iconOpacity = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [5.9: 0, 6: 1]))
// "name" references the "name" key in an MLNPointFeature’s attributes dictionary.
symbols.text = NSExpression(forKeyPath: "name")
symbols.textColor = symbols.iconColor
symbols.textFontSize = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [10: 10, 16: 16]))
symbols.textTranslation = NSExpression(forConstantValue: NSValue(cgVector: CGVector(dx: 15, dy: 0)))
symbols.textOpacity = symbols.iconOpacity
symbols.textHaloColor = symbols.iconHaloColor
symbols.textHaloWidth = symbols.iconHaloWidth
symbols.textJustification = NSExpression(forConstantValue: NSValue(mlnTextJustification: .left))
symbols.textAnchor = NSExpression(forConstantValue: NSValue(mlnTextAnchor: .left))
style.addLayer(circles)
style.addLayer(symbols)
}
// MARK: - Feature interaction
@IBAction func handleMapTap(sender: UITapGestureRecognizer) {
if sender.state == .ended {
// Limit feature selection to just the following layer identifiers.
let layerIdentifiers: Set = ["lighthouse-symbols", "lighthouse-circles"]
// Try matching the exact point first.
let point = sender.location(in: sender.view!)
for feature in mapView.visibleFeatures(at: point, styleLayerIdentifiers: layerIdentifiers)
where feature is MLNPointFeature
{
guard let selectedFeature = feature as? MLNPointFeature else {
fatalError("Failed to cast selected feature as MLNPointFeature")
}
showCallout(feature: selectedFeature)
return
}
let touchCoordinate = mapView.convert(point, toCoordinateFrom: sender.view!)
let touchLocation = CLLocation(latitude: touchCoordinate.latitude, longitude: touchCoordinate.longitude)
// Otherwise, get all features within a rect the size of a touch (44x44).
let touchRect = CGRect(origin: point, size: .zero).insetBy(dx: -22.0, dy: -22.0)
let possibleFeatures = mapView.visibleFeatures(in: touchRect, styleLayerIdentifiers: Set(layerIdentifiers)).filter { $0 is MLNPointFeature }
// Select the closest feature to the touch center.
let closestFeatures = possibleFeatures.sorted(by: {
CLLocation(latitude: $0.coordinate.latitude, longitude: $0.coordinate.longitude).distance(from: touchLocation) < CLLocation(latitude: $1.coordinate.latitude, longitude: $1.coordinate.longitude).distance(from: touchLocation)
})
if let feature = closestFeatures.first {
guard let closestFeature = feature as? MLNPointFeature else {
fatalError("Failed to cast selected feature as MLNPointFeature")
}
showCallout(feature: closestFeature)
return
}
// If no features were found, deselect the selected annotation, if any.
mapView.deselectAnnotation(mapView.selectedAnnotations.first, animated: true)
}
}
func showCallout(feature: MLNPointFeature) {
let point = MLNPointFeature()
point.title = feature.attributes["name"] as? String
point.coordinate = feature.coordinate
// Selecting an feature that doesn’t already exist on the map will add a new annotation view.
// We’ll need to use the map’s delegate methods to add an empty annotation view and remove it when we’re done selecting it.
mapView.selectAnnotation(point, animated: true, completionHandler: nil)
}
// MARK: - MLNMapViewDelegate
func mapView(_: MLNMapView, annotationCanShowCallout _: MLNAnnotation) -> Bool {
true
}
func mapView(_ mapView: MLNMapView, didDeselect annotation: MLNAnnotation) {
mapView.removeAnnotations([annotation])
}
func mapView(_: MLNMapView, viewFor _: MLNAnnotation) -> MLNAnnotationView? {
// Create an empty view annotation. Set a frame to offset the callout.
MLNAnnotationView(frame: CGRect(x: 0, y: 0, width: 20, height: 20))
}
// MARK: - Data fetching and parsing
func fetchPoints(withCompletion completion: @escaping (([MLNPointFeature]) -> Void)) {
// Wikidata query for all lighthouses in the United States: http://tinyurl.com/zrl2jc4
let query = "SELECT DISTINCT ?item " +
"?itemLabel ?coor ?image " +
"WHERE " +
"{ " +
"?item wdt:P31 wd:Q39715 . " +
"?item wdt:P17 wd:Q30 . " +
"?item wdt:P625 ?coor . " +
"OPTIONAL { ?item wdt:P18 ?image } . " +
"SERVICE wikibase:label { bd:serviceParam wikibase:language \"en\" } " +
"} " +
"ORDER BY ?itemLabel"
let characterSet = NSMutableCharacterSet()
characterSet.formUnion(with: CharacterSet.urlQueryAllowed)
characterSet.removeCharacters(in: "?")
characterSet.removeCharacters(in: "&")
characterSet.removeCharacters(in: ":")
let encodedQuery = query.addingPercentEncoding(withAllowedCharacters: characterSet as CharacterSet)!
let request = URLRequest(url: URL(string: "https://query.wikidata.org/sparql?query=\(encodedQuery)&format=json")!)
URLSession.shared.dataTask(with: request, completionHandler: { data, _, error in
guard error == nil else {
preconditionFailure("Failed to load GeoJSON data: \(error!)")
}
guard
let data,
let json = try? JSONSerialization.jsonObject(with: data, options: []) as? [String: AnyObject],
let results = json["results"] as? [String: AnyObject],
let items = results["bindings"] as? [[String: AnyObject]]
else {
preconditionFailure("Failed to parse GeoJSON data")
}
DispatchQueue.main.async {
completion(self.parseJSONItems(items: items))
}
}).resume()
}
func parseJSONItems(items: [[String: AnyObject]]) -> [MLNPointFeature] {
var features = [MLNPointFeature]()
for item in items {
guard let label = item["itemLabel"] as? [String: AnyObject],
let title = label["value"] as? String else { continue }
guard let coor = item["coor"] as? [String: AnyObject],
let point = coor["value"] as? String else { continue }
let parsedPoint = point.replacingOccurrences(of: "Point(", with: "").replacingOccurrences(of: ")", with: "")
let pointComponents = parsedPoint.components(separatedBy: " ")
let coordinate = CLLocationCoordinate2D(latitude: Double(pointComponents[1])!, longitude: Double(pointComponents[0])!)
let feature = MLNPointFeature()
feature.coordinate = coordinate
feature.title = title
// A feature’s attributes can used by runtime styling for things like text labels.
feature.attributes = [
"name": title,
]
features.append(feature)
}
return features
}
}
```
![](WebAPIDataExample.png)

6
platform/ios/app-swift/BUILD.bazel
View File

@@ -10,6 +10,9 @@ configure_device_profiles()
swift_library(
name = "Sources",
srcs = glob(["Sources/*.swift"]),
data = glob([
"Data/*",
]),
module_name = "Sources",
tags = ["manual"],
deps = [
@@ -27,9 +30,6 @@ ios_application(
infoplists = [":Info.plist"],
minimum_os_version = "16.0",
provisioning_profile = "xcode_profile",
resources = glob([
"Data/*",
]),
visibility = ["@rules_xcodeproj//xcodeproj:generated"],
deps = [":Sources"],
)

BIN
platform/ios/app-swift/Data/lighthouse.png Normal file
View File

Binary file not shown.
Side by Side

After

Width:  |  Height:  |  Size: 1.4 KiB

5
platform/ios/app-swift/Sources/LineStyleLayerExampleUIKit.swift
View File

@@ -69,8 +69,7 @@ class LineStyleLayerExampleUIKit: UIViewController, MLNMapViewDelegate {
layer.lineColor = NSExpression(forConstantValue: UIColor(red: 59 / 255, green: 178 / 255, blue: 208 / 255, alpha: 1))
// Use `NSExpression` to smoothly adjust the line width from 2pt to 20pt between zoom levels 14 and 18. The `interpolationBase` parameter allows the values to interpolate along an exponential curve.
layer.lineWidth = NSExpression(format: "mgl_interpolate:withCurveType:parameters:stops:($zoomLevel, 'linear', nil, %@)",
[14: 2, 18: 20])
layer.lineWidth = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [14: 2, 18: 20]))
// We can also add a second layer that will draw a stroke around the original line.
let casingLayer = MLNLineStyleLayer(identifier: "polyline-case", source: source)
@@ -82,7 +81,7 @@ class LineStyleLayerExampleUIKit: UIViewController, MLNMapViewDelegate {
// Stroke color slightly darker than the line color.
casingLayer.lineColor = NSExpression(forConstantValue: UIColor(red: 41 / 255, green: 145 / 255, blue: 171 / 255, alpha: 1))
// Use `NSExpression` to gradually increase the stroke width between zoom levels 14 and 18.
casingLayer.lineWidth = NSExpression(format: "mgl_interpolate:withCurveType:parameters:stops:($zoomLevel, 'linear', nil, %@)", [14: 1, 18: 4])
casingLayer.lineWidth = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [14: 1, 18: 4]))
// Just for fun, let’s add another copy of the line with a dash pattern.
let dashedLayer = MLNLineStyleLayer(identifier: "polyline-dash", source: source)

3
platform/ios/app-swift/Sources/MapLibreNavigationView.swift
View File

@@ -20,6 +20,9 @@ struct MapLibreNavigationView: View {
NavigationLink("LineStyleLayerExample") {
LineStyleLayerExampleUIViewControllerRepresentable()
}
NavigationLink("WebAPIDataExampleUIKit") {
WebAPIDataExampleUIViewControllerRepresentable()
}
}
}
}

230
platform/ios/app-swift/Sources/WebAPIDataExampleUIKit.swift Normal file
View File

@@ -0,0 +1,230 @@
import MapLibre
import SwiftUI
import UIKit
// #-example-code(WebAPIDataExampleUIKit)
class WebAPIDataExampleUIKit: UIViewController, MLNMapViewDelegate {
var mapView: MLNMapView!
override func viewDidLoad() {
super.viewDidLoad()
mapView = MLNMapView(frame: view.bounds)
mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
mapView.setCenter(CLLocationCoordinate2D(latitude: 37.090240, longitude: -95.712891), zoomLevel: 2, animated: false)
mapView.delegate = self
mapView.attributionButton.isHidden = true
view.addSubview(mapView)
// Add a single tap gesture recognizer. This gesture requires the built-in MLNMapView tap gestures (such as those for zoom and annotation selection) to fail.
let singleTap = UITapGestureRecognizer(target: self, action: #selector(handleMapTap(sender:)))
for recognizer in mapView.gestureRecognizers! where recognizer is UITapGestureRecognizer {
singleTap.require(toFail: recognizer)
}
mapView.addGestureRecognizer(singleTap)
}
func mapView(_: MLNMapView, didFinishLoading _: MLNStyle) {
fetchPoints { [weak self] features in
self?.addItemsToMap(features: features)
}
}
func addItemsToMap(features: [MLNPointFeature]) {
// MLNMapView.style is optional, so you must guard against it not being set.
guard let style = mapView.style else { return }
// You can add custom UIImages to the map style.
// These can be referenced by an MLNSymbolStyleLayer’s iconImage property.
style.setImage(UIImage(named: "lighthouse")!, forName: "lighthouse")
// Add the features to the map as a shape source.
let source = MLNShapeSource(identifier: "us-lighthouses", features: features, options: nil)
style.addSource(source)
let lighthouseColor = UIColor(red: 0.08, green: 0.44, blue: 0.96, alpha: 1.0)
// Use MLNCircleStyleLayer to represent the points with simple circles.
// In this case, we can use style functions to gradually change properties between zoom level 2 and 7: the circle opacity from 50% to 100% and the circle radius from 2pt to 3pt.
let circles = MLNCircleStyleLayer(identifier: "lighthouse-circles", source: source)
circles.circleColor = NSExpression(forConstantValue: lighthouseColor)
// The circles should increase in opacity from 0.5 to 1 based on zoom level.
circles.circleOpacity = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [2: 0.5, 7: 1]))
circles.circleRadius = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [2: 2, 7: 3]))
// Use MLNSymbolStyleLayer for more complex styling of points including custom icons and text rendering.
let symbols = MLNSymbolStyleLayer(identifier: "lighthouse-symbols", source: source)
symbols.iconImageName = NSExpression(forConstantValue: "lighthouse")
symbols.iconColor = NSExpression(forConstantValue: lighthouseColor)
symbols.iconScale = NSExpression(forConstantValue: 0.5)
symbols.iconHaloColor = NSExpression(forConstantValue: UIColor.white.withAlphaComponent(0.5))
symbols.iconHaloWidth = NSExpression(forConstantValue: 1)
symbols.iconOpacity = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [5.9: 0, 6: 1]))
// "name" references the "name" key in an MLNPointFeature’s attributes dictionary.
symbols.text = NSExpression(forKeyPath: "name")
symbols.textColor = symbols.iconColor
symbols.textFontSize = NSExpression(forMLNInterpolating: NSExpression.zoomLevelVariable, curveType: MLNExpressionInterpolationMode.linear, parameters: nil, stops: NSExpression(forConstantValue: [10: 10, 16: 16]))
symbols.textTranslation = NSExpression(forConstantValue: NSValue(cgVector: CGVector(dx: 15, dy: 0)))
symbols.textOpacity = symbols.iconOpacity
symbols.textHaloColor = symbols.iconHaloColor
symbols.textHaloWidth = symbols.iconHaloWidth
symbols.textJustification = NSExpression(forConstantValue: NSValue(mlnTextJustification: .left))
symbols.textAnchor = NSExpression(forConstantValue: NSValue(mlnTextAnchor: .left))
style.addLayer(circles)
style.addLayer(symbols)
}
// MARK: - Feature interaction
@IBAction func handleMapTap(sender: UITapGestureRecognizer) {
if sender.state == .ended {
// Limit feature selection to just the following layer identifiers.
let layerIdentifiers: Set = ["lighthouse-symbols", "lighthouse-circles"]
// Try matching the exact point first.
let point = sender.location(in: sender.view!)
for feature in mapView.visibleFeatures(at: point, styleLayerIdentifiers: layerIdentifiers)
where feature is MLNPointFeature
{
guard let selectedFeature = feature as? MLNPointFeature else {
fatalError("Failed to cast selected feature as MLNPointFeature")
}
showCallout(feature: selectedFeature)
return
}
let touchCoordinate = mapView.convert(point, toCoordinateFrom: sender.view!)
let touchLocation = CLLocation(latitude: touchCoordinate.latitude, longitude: touchCoordinate.longitude)
// Otherwise, get all features within a rect the size of a touch (44x44).
let touchRect = CGRect(origin: point, size: .zero).insetBy(dx: -22.0, dy: -22.0)
let possibleFeatures = mapView.visibleFeatures(in: touchRect, styleLayerIdentifiers: Set(layerIdentifiers)).filter { $0 is MLNPointFeature }
// Select the closest feature to the touch center.
let closestFeatures = possibleFeatures.sorted(by: {
CLLocation(latitude: $0.coordinate.latitude, longitude: $0.coordinate.longitude).distance(from: touchLocation) < CLLocation(latitude: $1.coordinate.latitude, longitude: $1.coordinate.longitude).distance(from: touchLocation)
})
if let feature = closestFeatures.first {
guard let closestFeature = feature as? MLNPointFeature else {
fatalError("Failed to cast selected feature as MLNPointFeature")
}
showCallout(feature: closestFeature)
return
}
// If no features were found, deselect the selected annotation, if any.
mapView.deselectAnnotation(mapView.selectedAnnotations.first, animated: true)
}
}
func showCallout(feature: MLNPointFeature) {
let point = MLNPointFeature()
point.title = feature.attributes["name"] as? String
point.coordinate = feature.coordinate
// Selecting an feature that doesn’t already exist on the map will add a new annotation view.
// We’ll need to use the map’s delegate methods to add an empty annotation view and remove it when we’re done selecting it.
mapView.selectAnnotation(point, animated: true, completionHandler: nil)
}
// MARK: - MLNMapViewDelegate
func mapView(_: MLNMapView, annotationCanShowCallout _: MLNAnnotation) -> Bool {
true
}
func mapView(_ mapView: MLNMapView, didDeselect annotation: MLNAnnotation) {
mapView.removeAnnotations([annotation])
}
func mapView(_: MLNMapView, viewFor _: MLNAnnotation) -> MLNAnnotationView? {
// Create an empty view annotation. Set a frame to offset the callout.
MLNAnnotationView(frame: CGRect(x: 0, y: 0, width: 20, height: 20))
}
// MARK: - Data fetching and parsing
func fetchPoints(withCompletion completion: @escaping (([MLNPointFeature]) -> Void)) {
// Wikidata query for all lighthouses in the United States: http://tinyurl.com/zrl2jc4
let query = "SELECT DISTINCT ?item " +
"?itemLabel ?coor ?image " +
"WHERE " +
"{ " +
"?item wdt:P31 wd:Q39715 . " +
"?item wdt:P17 wd:Q30 . " +
"?item wdt:P625 ?coor . " +
"OPTIONAL { ?item wdt:P18 ?image } . " +
"SERVICE wikibase:label { bd:serviceParam wikibase:language \"en\" } " +
"} " +
"ORDER BY ?itemLabel"
let characterSet = NSMutableCharacterSet()
characterSet.formUnion(with: CharacterSet.urlQueryAllowed)
characterSet.removeCharacters(in: "?")
characterSet.removeCharacters(in: "&")
characterSet.removeCharacters(in: ":")
let encodedQuery = query.addingPercentEncoding(withAllowedCharacters: characterSet as CharacterSet)!
let request = URLRequest(url: URL(string: "https://query.wikidata.org/sparql?query=\(encodedQuery)&format=json")!)
URLSession.shared.dataTask(with: request, completionHandler: { data, _, error in
guard error == nil else {
preconditionFailure("Failed to load GeoJSON data: \(error!)")
}
guard
let data,
let json = try? JSONSerialization.jsonObject(with: data, options: []) as? [String: AnyObject],
let results = json["results"] as? [String: AnyObject],
let items = results["bindings"] as? [[String: AnyObject]]
else {
preconditionFailure("Failed to parse GeoJSON data")
}
DispatchQueue.main.async {
completion(self.parseJSONItems(items: items))
}
}).resume()
}
func parseJSONItems(items: [[String: AnyObject]]) -> [MLNPointFeature] {
var features = [MLNPointFeature]()
for item in items {
guard let label = item["itemLabel"] as? [String: AnyObject],
let title = label["value"] as? String else { continue }
guard let coor = item["coor"] as? [String: AnyObject],
let point = coor["value"] as? String else { continue }
let parsedPoint = point.replacingOccurrences(of: "Point(", with: "").replacingOccurrences(of: ")", with: "")
let pointComponents = parsedPoint.components(separatedBy: " ")
let coordinate = CLLocationCoordinate2D(latitude: Double(pointComponents[1])!, longitude: Double(pointComponents[0])!)
let feature = MLNPointFeature()
feature.coordinate = coordinate
feature.title = title
// A feature’s attributes can used by runtime styling for things like text labels.
feature.attributes = [
"name": title,
]
features.append(feature)
}
return features
}
}
// #-end-example-code
struct WebAPIDataExampleUIViewControllerRepresentable: UIViewControllerRepresentable {
typealias UIViewControllerType = WebAPIDataExampleUIKit
func makeUIViewController(context _: Context) -> WebAPIDataExampleUIKit {
WebAPIDataExampleUIKit()
}
func updateUIViewController(_: WebAPIDataExampleUIKit, context _: Context) {}
}