I have a MKPointAnnotation that I have setup and it displays where I would like it to however it comes with the default big red pin icon over the dot and I would like to hide that image and display nothing instead. I've tried working with the section I have commented below with "*****" and what I thought might work is setting view.image=nil and this did not change anything and I also tried view.frame.size=CGSize(width: 0, height: 0) which had no effect. Any other suggestions for how to accomplish this?
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
let annotation = annotation
let identifier = "marker"
var view: MKMarkerAnnotationView
if let dequeuedView = mapView.dequeueReusableAnnotationView(withIdentifier: identifier)
as? MKMarkerAnnotationView {
dequeuedView.annotation = annotation
view = dequeuedView
} else {
//************************
view = MKMarkerAnnotationView(annotation: annotation, reuseIdentifier: identifier)
view.frame.size=CGSize(width: 0, height: 0)
view.canShowCallout = true
view.calloutOffset = CGPoint(x: -5, y: 5)
view.rightCalloutAccessoryView = UIButton(type: .detailDisclosure)
}
return view
}
This was actually easier to solve than I was expecting, all I needed to do was set the markerTintColor to a color with alpha of 0.
view.markerTintColor=UIColor(red: 0.0/255.0, green: 0.0/255.0, blue: 0.0/255.0,alpha:0.5).withAlphaComponent(0)
is what solved it for me in this case.
Here is the apple documentation on the subject:
https://developer.apple.com/documentation/mapkit/mapkit_annotations/annotating_a_map_with_custom_data
They seem to recommend coding a custom Annotation as seen:
class SanFranciscoAnnotation: NSObject, MKAnnotation {
// This property must be key-value observable, which the `#objc dynamic` attributes provide.
#objc dynamic var coordinate = CLLocationCoordinate2D(latitude: 37.779_379, longitude: -122.418_433)
// Required if you set the annotation view's `canShowCallout` property to `true`
var title: String? = NSLocalizedString("SAN_FRANCISCO_TITLE", comment: "SF annotation")
// This property defined by `MKAnnotation` is not required.
var subtitle: String? = NSLocalizedString("SAN_FRANCISCO_SUBTITLE", comment: "SF annotation") }
You can try creating a custom annotation in this way with a clear color or with a size of (0,0). Assign your view to the custom annotation you code.
var view: SanFranciscoAnnotation
If this doesn't work, I will dig up some old code from an app I wrote with custom annotations and share that.
Related
The use case I have is one where I want to draw and label counties in a state. Annotations don't seem like the right approach to solve this problem. First of all, the label refers to region rather than a point. Second, there are far too many; so, I would have to selectively show and hide annotations based on zoom level (actually something more like the size of the MKCoordinateRegion span). Lastly, county labels are not all that relevant unless the user starts zooming in.
Just as a side note, county boundaries may be present in map tiles, but they are not emphasized. Moreover, there are a multitude of other boundaries I might want to draw that are completely absent from map tiles.
Ultimately, what I want to do is create an overlay for each county shape (counties are clickable and I can navigate to details) and another set of overlays for the labels. I separate county shapes and labels because county shapes are messy and I just use the center of the county. There is no guarantee with this approach that labels will not draw outside of county shapes, which means labels could end up getting clipped when other counties are drawn.
Drawing the county shapes was relatively easy or at least relatively well documented. I do not include any code on rendering shapes. Drawing text on the other hand is not straight forward, not well documented, and most of the posts on the subject are ancient. The lack of recent posts on the subject as well as the fact that most posts posit solutions that no longer work, use deprecated APIs, or only solve a part of the problem motivates this post. Of course, the lack of activity on this problem could be because my strategy is mind numbingly stupid.
I have posted a complete solution to the problem. If you can improve on the solution below or believe there is a better way, I would appreciate the feedback. Alternatively, if you are trying to find a solution to this problem, you will find this post more helpful than the dozens I have looked at, which on the whole got me to where I am now.
Below is a complete solution that can be run in an Xcode single view Playground. I am running Xcode 14.2. The most important bit of code is the overridden draw function of LabelOverlayRenderer. That bit of code is what I struggled to craft for more than a day. I almost gave up. Another key point is when drawing text, one uses CoreText. The APIs pertaining to drawing and managing text are many and most have had a lot of name changes and deprecation.
import UIKit
import MapKit
import SwiftUI
class LabelOverlayRenderer: MKOverlayRenderer {
let title: String
let center: CLLocationCoordinate2D
init(overlay: LabelOverlay) {
center = overlay.coordinate
title = overlay.title!
super.init(overlay: overlay)
}
override func draw(_ mapRect: MKMapRect, zoomScale: MKZoomScale, in context: CGContext) {
context.saveGState()
// Set Drawing mode
context.setTextDrawingMode(.fillStroke)
// If I don't do this, the text is upside down.
context.textMatrix = CGAffineTransformMakeScale(1.0, -1.0);
// Text size is crazy big because label has to be miles across
// to be visible.
var attrs = [ NSAttributedString.Key : Any]()
attrs[NSAttributedString.Key.font] = UIFont(name: "Helvetica", size: 128000.0)!
attrs[NSAttributedString.Key.foregroundColor] = UIColor(Color.red)
let attributedString = NSAttributedString(string: title, attributes: attrs)
let line = CTLineCreateWithAttributedString(attributedString)
// Get the size of the whole string, so the string can
// be centered. CGSize is huge because I don't want
// to clip or wrap the string. The range setting
// is just cut and paste. Looks like a place holder.
// Ideally, it is the range of that portion
// of the string for which I want the size.
let frameSetter = CTFramesetterCreateWithAttributedString(attributedString)
let size = CTFramesetterSuggestFrameSizeWithConstraints(frameSetter, CFRangeMake(0, 0), nil, CGSize(width: 1000000, height: 1000000), nil)
// Center is lat-lon, but map is in meters (maybe? definitely
// not lat-lon). Center string and draw.
var p = point(for: MKMapPoint(center))
p.x -= size.width/2
p.y += size.height/2
// There is no "at" on CTLineDraw. The string
// is positioned in the context.
context.textPosition = p
CTLineDraw(line, context)
context.restoreGState()
}
}
class LabelOverlay: NSObject, MKOverlay {
let title: String?
let coordinate: CLLocationCoordinate2D
let boundingMapRect: MKMapRect
init(title: String, coordinate: CLLocationCoordinate2D, boundingMapRect: MKMapRect) {
self.title = title
self.coordinate = coordinate
self.boundingMapRect = boundingMapRect
}
}
class MapViewCoordinator: NSObject, MKMapViewDelegate {
func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
if let overlay = overlay as? LabelOverlay {
return LabelOverlayRenderer(overlay: overlay)
}
fatalError("Unknown overlay type!")
}
}
struct MyMapView: UIViewRepresentable {
func makeCoordinator() -> MapViewCoordinator {
return MapViewCoordinator()
}
func updateUIView(_ view: MKMapView, context: Context){
// Center on Georgia
let center = CLLocationCoordinate2D(latitude: 32.6793, longitude: -83.62245)
let span = MKCoordinateSpan(latitudeDelta: 4.875, longitudeDelta: 5.0003)
let region = MKCoordinateRegion(center: center, span: span)
view.setRegion(region, animated: true)
view.delegate = context.coordinator
let coordinate = CLLocationCoordinate2D(latitude: 32.845084, longitude: -84.3742)
let mapRect = MKMapRect(x: 70948460.0, y: 107063759.0, width: 561477.0, height: 613908.0)
let overlay = LabelOverlay(title: "Hello World!", coordinate: coordinate, boundingMapRect: mapRect)
view.addOverlay(overlay)
}
func makeUIView(context: Context) -> MKMapView {
// Create a map with constrained zoom gestures only
let mapView = MKMapView(frame: .zero)
mapView.isPitchEnabled = false
mapView.isRotateEnabled = false
let zoomRange = MKMapView.CameraZoomRange(
minCenterCoordinateDistance: 160000,
maxCenterCoordinateDistance: 1400000
)
mapView.cameraZoomRange = zoomRange
return mapView
}
}
struct ContentView: View {
var body: some View {
VStack {
MyMapView()
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
For some reason, when I try to draw two MKPolygons on a mapView (MKMapView) I end up with the two polygons connected. Drawing each polygon individually works fine. And I've verified that each of the polygons don't contain any of the coordinates to form the connection between the two. I've attached an image with the two polygons connected
For reference, here's where I call to add the polygons.
func addPeakTimePolygon(from coordinatesArray: [CLLocationCoordinate2D], title: Int){
let polygon = MKPolygon(coordinates: coordinatesArray, count: coordinatesArray.count)
polygon.title = String(title)
//Should refactor to use .contains(where:
var shouldAdd = true
for polygon in self.currentPolygons{
if polygon.title == String(title){
shouldAdd = false
}
}
if shouldAdd{
self.currentPolygons.append(polygon)
self.mapView.add(polygon)
}
}
And here's my rendererFor code:
func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
if overlay is MKPolyline {
let renderer = MKPolylineRenderer(overlay: overlay)
renderer.strokeColor = #colorLiteral(red: 0, green: 0.6862745098, blue: 0.7607843137, alpha: 1)
renderer.lineWidth = 5.0
return renderer
}
else if overlay is MKPolygon {
let renderer = MKPolygonRenderer(overlay: overlay)
renderer.fillColor = UIColor.red.withAlphaComponent(0.5)
renderer.strokeColor = UIColor.red
renderer.lineWidth = 2
return renderer
}
return MKOverlayRenderer()
}
It seems like you're making one overlay consisting of two polygons. You can't do that with an MKPolygonRenderer; you will get one polygon, as you are observing.
You will need separate overlays, one for each polygon. Unless you are using iOS 13! In that case, you are in luck: New in iOS 13, multiple polygons or polylines can be combined into an MKMultiPolygon or MKMultiPolyline and drawn by an MKMultiPolygonRenderer or MKMultiPolylineRenderer.
I forgot to check / post the code that was calling addPeakTimePolygon. Here is the problematic code below:
var locationList: [CLLocationCoordinate2D] = []
var title = 0
if let peakTimeCampaignList = data["PeakTimeRewardCampaignList"] as? [[AnyHashable:Any]]{
for campaign in peakTimeCampaignList{
if let polygonPoints = campaign["CampaignPolygon"] as? [[AnyHashable:Any]]{
for polygonPoint in polygonPoints{
let polygonPoint = CLLocationCoordinate2D(latitude: polygonPoint["Latitude"] as! CLLocationDegrees, longitude: polygonPoint["Longitude"] as! CLLocationDegrees)
locationList.append(polygonPoint)
}
}
if let id = campaign["Id"] as? Int{
title = id
}
mapBundle.addPeakTimePolygon(from: locationList, title: title)
}
}
As you can see locationList wasn't being cleared out within the loop, causing whatever we sent over to addPeakTimePolygon to have coordinates from two polygons and MapKit was trying it's best to form a polygon between them.
This was a dumb mistake, but hoping someone else sees this with the same problem!
I am trying to change the color of an existing MKOverlay on a map.
I am add several MKPolygons as unique overlays to mapView. As they are rendered, the overlay's color is applied by the mapView rendererFor function.
Periodically I would like to change the color of an existing overlay; ideally without removingAll and re-adding. I have code that will handle the color change, but I do not know how to identify different overlays other than by their type (MKPolygon, MKCircle) - but all overlays in my situation are MKPolygon, so executing the code simply changes all.
I have tried converting the MKPolygon into an MKOverlay before using addOverlay and manipulating the title, but title is "get-only"
I have tried subclassing MKPolygon, but my reading says this is bad in Swift.
I add the overlay like this.
var shapeNW:MKMapPoint = MKMapPoint( CLLocationCoordinate2D(latitude: 48.313319, longitude: -124.109715))
var shapeNE:MKMapPoint = MKMapPoint( CLLocationCoordinate2D(latitude: 48.313312, longitude: -124.108695))
var shapeSW:MKMapPoint = MKMapPoint( CLLocationCoordinate2D(latitude: 48.312661, longitude: -124.109767))
var shapeSE:MKMapPoint = MKMapPoint( CLLocationCoordinate2D(latitude: 48.312626, longitude: -124.108679))
var myShapePoints:[MKMapPoint] = [shapeNW,shapeNE,shapeSE,shapeSW]
// addAnItemToMap(title: "Circle", locationName: "CircleName", type: "SS", coordinate: feiLocation, horizontalAccuracy: 20)
var myShape:MKPolygon = MKPolygon(points: myShapePoints, count: 4)
mapView.addOverlay(myShape)
Here is my function that I use to change the color after it is created. But obviously this function changes the color of all items as it cannot identify which overlay to change. This is my issue, I would like to identify the specific overlay and change just it.
func changeColor(identifier: String) {
let overlays = self.mapView.overlays
let duration:TimeInterval = 5.0
for overlay in overlays {
if identifier == "on"{
let renderer = mapView.renderer(for: overlay) as! MKPolygonRenderer
DispatchQueue.main.async{
renderer.alpha = 1.0
renderer.fillColor = UIColor.blue
}
}
else {
let renderer = mapView.renderer(for: overlay) as! MKPolygonRenderer
DispatchQueue.main.async{
renderer.alpha = 0.0
}
}
}
}
You can just subclass MKPolygon:
class CustomPolygon: MKPolygon {
var identifier: String? = nil
}
Then you can configure your renderer accordingly:
func configureColor(of renderer: MKPolygonRenderer, for overlay: MKOverlay) {
let baseColor: UIColor
if let polygon = overlay as? CustomPolygon, polygon.identifier == "on" {
baseColor = .cyan
} else {
baseColor = .red
}
renderer.strokeColor = baseColor.withAlphaComponent(0.75)
renderer.fillColor = baseColor.withAlphaComponent(0.25)
}
Then your main renderer(for:) can use that:
extension ViewController: MKMapViewDelegate {
func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
let renderer = MKPolygonRenderer(overlay: overlay)
renderer.lineWidth = 5
configureColor(of: renderer, for: overlay)
return renderer
}
}
As can your update routine can:
func updateColors() {
for overlay in mapView.overlays {
if let renderer = mapView.renderer(for: overlay) as? MKPolygonRenderer {
configureColor(of: renderer, for: overlay)
}
}
}
Personally, rather than having overlays whose identifier is not "on" have an alpha of 0, I just would remove those overlays from the map, and then you don’t have to deal with any of this.
I use the code below on view did load to add a custom annotation icon for the map center that the user started at so that if they scroll away they can always see their starting point.
if let lat = curBlip.blip_lat, let lon = curBlip.blip_lon {
let mapCenter = CLLocationCoordinate2DMake(lat, lon)
let mapSpan = MKCoordinateSpanMake(0.01, 0.01)
let mapRegion = MKCoordinateRegionMake(mapCenter, mapSpan)
self.map.setRegion(mapRegion, animated: true)
let coordinate = CLLocationCoordinate2D(latitude: lat, longitude: lon)
let annotation = MKPointAnnotation()
annotation.coordinate = coordinate
annotation.title = "Your Blips Location"
annotation.subtitle = "Subtitle Placeholder"
self.map.addAnnotation(annotation)
When the view loads I load that annotation so its always first and I set a bool named "set" to true after the first annotation to ensure that it gets the custom icon. The issue I am having is that even though I have the annotation set to display priority required the annotation disappears when I move the map away. How can I make that annotation always persist or is there a better way to set a "this is where the map started" circle that doesn't go away?
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
if set {
return nil
} else {
let view = MKAnnotationView(annotation: annotation, reuseIdentifier: "annotationId")
view.image = UIImage(named: "locationArea50")
view.canShowCallout = true
view.displayPriority = .required
set = true
return view
}
Then after I scroll the map away a little bit, I suspect scrolling far enough that the system has to make them reappear the annotation disappears. I assume this has to do with how the grouping of annotations works but that blue annotation is special and I want it to always be present, which is what I thought displayPriority did.
The default value of displayPriority is .required .
So for correct overlapping you need to downgrade priority of red annotations:
redAnnotation.displayPriority = .defaultHigh
I would like to customize my annotations (pins) so I would be able to change its image. I used a function (mapview) to change the picture, so I don’t know if I should use it again to change the picture of another group of pins; let´s say I have two locations, a restaurant and a hospital, so I want to put a plate and a red cross respectively. Here is my function code:
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
if annotation is MKUserLocation {
return nil
}
var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: "identifier")
if annotationView == nil{
annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: "identifier")
annotationView!.canShowCallout = true
annotationView!.rightCalloutAccessoryView = UIButton(type: .detailDisclosure)
let pinImg = UIImage(named: "curz")
let size = CGSize(width: 50, height: 50)
UIGraphicsBeginImageContext(size)
pinImg!.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
let resizedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
annotationView!.image = resizedImage
}
else {
annotationView!.annotation = annotation
}
return annotationView
}
You can return different annotation views for different places by comparing the coordinate information. ex:
if ((annotation.coordinate.latitude == theCoordinate1.latitude)
&& (annotation.coordinate.longitude == theCoordinate1.longitude))
{
return someAnnotationView
}
follow this link Adding different images to different annotation views in xcode
The correct way to return different views for different annotation types (or groups of different annotation types) is to subclass the annotation and assign a different reuse identifier for each one (during init). This identifier is similar to the table view cell identifier and is used to reuse (rather than create from scratch) a cell when it scrolls out of sight. The same is true for annotations, rather than create a new one each time a 'discarded' annotation can be reused.
Then in mapview viewfor annotation you can test for annotation.identifier And assign the correct image.