I just wrote this class that does the job:
import android.content.Context;
import android.graphics.Color;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.PointCollection;
import com.esri.arcgisruntime.geometry.Polygon;
import com.esri.arcgisruntime.geometry.SpatialReference;
import com.esri.arcgisruntime.mapping.view.Graphic;
import com.esri.arcgisruntime.mapping.view.GraphicsOverlay;
import com.esri.arcgisruntime.symbology.SimpleFillSymbol;
import com.esri.arcgisruntime.symbology.SimpleLineSymbol;
import java.util.List;
public class ARCGISCircle {
private Point center;
private double radius;
private int strokeColor;
private double strokeWidth;
private SimpleLineSymbol.Style strokePattern;
private int fillColor;
private SimpleFillSymbol.Style fillPattern;
private int pointCount;
private int zIndex;
private Context context;
private SpatialReference spatialReference;
private Graphic graphicCircle;
private static final int POINT_COUNT = 36;
private static int EARTH_RADIUS = 6378800;
public ARCGISCircle(Builder builder) {
center = builder.center;
radius = builder.radius;
strokeColor = builder.strokeColor;
strokeWidth = builder.strokeWidth;
fillColor = builder.fillColor;
context = builder.context;
spatialReference = builder.spatialReference;
pointCount = builder.pointCount;
zIndex = builder.zIndex;
strokePattern = builder.strokePattern;
fillPattern = builder.fillPattern;
}
/**
* Add a circle on a graphic overlay
* @param graphicOverlay drawing sheet
* @return if the action was successfully completed
*/
public final boolean addCircleOn(GraphicsOverlay graphicOverlay){
boolean drawingOk = false;
if(graphicOverlay != null && radius > 0 && drawCircle()){
graphicOverlay.getGraphics().add(this.graphicCircle);
drawingOk = true;
}
return drawingOk;
}
/**
* Delete a circle
* @param graphicOverlay drawing sheet
* @return if the action was successfully completed
*/
public final boolean removeCircleFrom(GraphicsOverlay graphicOverlay){
boolean deletionOk = false;
if(graphicOverlay != null){
List<Graphic> itsGraphics = graphicOverlay.getGraphics();
if(itsGraphics != null && itsGraphics.size() > 0){
itsGraphics.remove(this.graphicCircle);
deletionOk = true;
}
}
return deletionOk;
}
/**
* Draw a graphic circle
* @return if the action was successfully completed
*/
private boolean drawCircle(){
boolean operationOk = false;
if(this.spatialReference != null ){
Polygon circlePolygon = drawPolygonCircle(this.center,this.radius,this.pointCount,this.spatialReference); //simple line symbol
if(circlePolygon != null){ //was successfully drawn
SimpleLineSymbol outlineSymbol = new SimpleLineSymbol(this.strokePattern, this.strokeColor, (float) this.strokeWidth);
SimpleFillSymbol fillSymbol = new SimpleFillSymbol(this.fillPattern, this.fillColor, outlineSymbol);
this.graphicCircle = new Graphic(circlePolygon,fillSymbol);
if(zIndex > -1)
this.graphicCircle.setZIndex(this.zIndex);
}
if(graphicCircle != null){
operationOk = true;
}
}
return operationOk;
}
/**
* Draw a polygon circle
* @param origin origin of the polygon
* @param radius in meters
* @param pointCount the number of point on the arc of the circle
* @param spatialReference the spatial reference
* @return a polygon formed of arc of circles
*/
private Polygon drawPolygonCircle(Point origin, double radius,int pointCount, SpatialReference spatialReference ){
if(radius > 0 && spatialReference != null && origin != null){
PointCollection corners = new PointCollection(spatialReference);
double radianFactor = 2*Math.PI/pointCount;
for(int i = 1; i <= pointCount; i++ ){
corners.add(getPolygonPoint(origin, radius, i * radianFactor));
}
return new Polygon(corners);
}
return null;
}
/**
* Defines the location of each point that will form the circle
* @param center the center of the final circle
* @param radius the radius of the circle
* @param angle the angle (formed by segment from the center to the radius)
* @return a new Location point
* Source: original code from : https://stackoverflow.com/a/13901270/3808178
*/
private Point getPolygonPoint(Point center, double radius, double angle) {
// Get the coordinates of a circle point at the given angle
double east = radius * Math.cos(angle);
double north = radius * Math.sin(angle);
double cLat = center.getY();
double cLng = center.getX();
double latRadius = EARTH_RADIUS * Math.cos(cLat / 180 * Math.PI);
double newLat = cLat + (north / EARTH_RADIUS / Math.PI * 180);
double newLng = cLng + (east / latRadius / Math.PI * 180);
return new Point(newLng,newLat);
}
/**
* Static builder class
*/
public static class Builder {
private Point center;
private double radius = 0;
private int strokeColor = Color.RED;
private double strokeWidth = 2;
private int fillColor = Color.RED;
private int pointCount = POINT_COUNT;
private int zIndex = -1;
private SimpleLineSymbol.Style strokePattern = SimpleLineSymbol.Style.SOLID;
private SimpleFillSymbol.Style fillPattern = SimpleFillSymbol.Style.SOLID;
private SpatialReference spatialReference;
private Context context;
public Builder(Context context,SpatialReference spatialReference) {
this.context = context;
this.spatialReference = spatialReference;
}
public Builder center(Point value) {
if(value == null)
throw new NullPointerException ("The location is null, it shouldn't be so.");
center = value;
return this;
}
public Builder radius(double value) {
radius = value;
return this;
}
public Builder strokeColor(int value) {
strokeColor = value;
return this;
}
public Builder strokeWidth(double value) {
strokeWidth = value;
return this;
}
public Builder fillColor(int value) {
fillColor = value;
return this;
}
public Builder pointCount(int value) {
pointCount = value;
return this;
}
public Builder zIndex(int value) {
zIndex = value;
return this;
}
public Builder strokePattern(SimpleLineSymbol.Style value) {
strokePattern = value;
return this;
}
public Builder fillPattern(SimpleFillSymbol.Style value) {
fillPattern = value;
return this;
}
public ARCGISCircle build() {
return new ARCGISCircle(this);
}
}
/**
* Get the graphic representing the circle
* @return
*/
public Graphic getGraphicCircle() {
return graphicCircle;
}
public void setVisible(boolean visible){
if(graphicCircle != null)
graphicCircle.setVisible(visible);
}
public boolean isVisible(){
boolean isVisible = false;
if(graphicCircle != null)
isVisible = graphicCircle.isVisible();
return isVisible;
}
}
And to call it you just do this:
/**
* Sets a radius describing the accuracy of the location
* @param location containing the radius and the coordinates of the center of the radius
*/
public void setRadius(Location location){
if(locationRadius != null)
locationRadius.removeCircleFrom(layer);
locationRadius = new ARCGISCircle.Builder(getApplicationContext(),wgs84)
.center(new Point(location.getLongitude(),location.getLatitude()))
.radius(location.getAccuracy())
.strokeColor(Color.RED)
.fillColor(Color.BLUE)
.fillPattern(SimpleFillSymbol.Style.CROSS)
//...
.build();
locationRadius.addCircleOn(layer);
}