Straight line distance

package com.mapbox.mapboxandroiddemo.examples.javaservices;
 
import android.graphics.Color;
import android.location.Location;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;
 
import com.mapbox.android.core.permissions.PermissionsListener;
import com.mapbox.android.core.permissions.PermissionsManager;
import com.mapbox.geojson.LineString;
import com.mapbox.geojson.Point;
import com.mapbox.mapboxandroiddemo.R;
import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.geometry.LatLng;
import com.mapbox.mapboxsdk.location.LocationComponent;
import com.mapbox.mapboxsdk.location.LocationComponentActivationOptions;
import com.mapbox.mapboxsdk.location.modes.CameraMode;
import com.mapbox.mapboxsdk.location.modes.RenderMode;
import com.mapbox.mapboxsdk.maps.MapView;
import com.mapbox.mapboxsdk.maps.MapboxMap;
import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;
import com.mapbox.mapboxsdk.maps.Style;
import com.mapbox.mapboxsdk.style.layers.LineLayer;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import com.mapbox.turf.TurfMeasurement;
 
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
 
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
 
import static com.mapbox.mapboxsdk.style.layers.Property.LINE_JOIN_ROUND;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.lineColor;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.lineJoin;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.lineWidth;
import static com.mapbox.turf.TurfConstants.UNIT_METERS;
 
/**
* Use {@link com.mapbox.turf.TurfMeasurement#distance(Point, Point)} to calculate a straight line distance
* ("as the crow flies") between the device location and the map camera's target.
*/
public class StraightLineDistanceMapMovementActivity extends AppCompatActivity implements
PermissionsListener, MapboxMap.OnCameraMoveListener {
 
private static final String DISTANCE_SOURCE_ID = "DISTANCE_SOURCE_ID";
private static final String DISTANCE_LINE_LAYER_ID = "DISTANCE_LINE_LAYER_ID";
 
// Adjust private static final variables below to change the example's UI
private static final int LINE_COLOR = Color.RED;
private static final float LINE_WIDTH = 2f;
 
private PermissionsManager permissionsManager;
private List<Point> pointList;
private MapView mapView;
private MapboxMap mapboxMap;
private TextView distanceTextView;
 
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
 
// Mapbox access token is configured here. This needs to be called either in your application
// object or in the same activity which contains the mapview.
Mapbox.getInstance(this, getString(R.string.access_token));
 
// This contains the MapView in XML and needs to be called after the access token is configured.
setContentView(R.layout.activity_javaservices_straight_line_distance);
 
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
 
mapView.getMapAsync(new OnMapReadyCallback() {
@Override
public void onMapReady(@NonNull MapboxMap mapboxMap) {
 
StraightLineDistanceMapMovementActivity.this.mapboxMap = mapboxMap;
 
mapboxMap.setStyle(new Style.Builder()
.fromUri(Style.DARK)
 
// Add the source to the map
.withSource(new GeoJsonSource(DISTANCE_SOURCE_ID))
 
// Style and add the LineLayer to the map.
.withLayer(new LineLayer(DISTANCE_LINE_LAYER_ID, DISTANCE_SOURCE_ID).withProperties(
lineColor(LINE_COLOR),
lineWidth(LINE_WIDTH),
lineJoin(LINE_JOIN_ROUND))), new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
enableLocationComponent(style);
 
StraightLineDistanceMapMovementActivity.this.mapboxMap
.addOnCameraMoveListener(StraightLineDistanceMapMovementActivity.this);
 
distanceTextView = findViewById(R.id.straight_line_distance_textview);
distanceTextView.setTextColor(Color.RED);
 
Toast.makeText(StraightLineDistanceMapMovementActivity.this,
getString(R.string.move_map_around_instruction), Toast.LENGTH_SHORT).show();
}
}
);
}
});
}
 
@Override
public void onCameraMove() {
redrawLine(mapboxMap.getCameraPosition().target);
}
 
private void redrawLine(@NonNull LatLng targetLatLng) {
mapboxMap.getStyle(new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
GeoJsonSource geoJsonSource = style.getSourceAs(DISTANCE_SOURCE_ID);
if (geoJsonSource != null) {
pointList = new ArrayList<>();
Location lastKnownLocation = mapboxMap.getLocationComponent().getLastKnownLocation();
if (lastKnownLocation != null) {
 
// Add the start and ending points to the straight line
Point targetPoint = Point.fromLngLat(targetLatLng.getLongitude(), targetLatLng.getLatitude());
Point deviceLocationPoint = Point.fromLngLat(lastKnownLocation.getLongitude(),
lastKnownLocation.getLatitude());
pointList.add(targetPoint);
pointList.add(deviceLocationPoint);
 
// Update the source with the new LineString line
geoJsonSource.setGeoJson(LineString.fromLngLats(pointList));
 
// Update the TextView with the new straight line distance
double distanceBetweenDeviceAndTarget = TurfMeasurement.distance(deviceLocationPoint,
targetPoint, UNIT_METERS);
 
distanceTextView.setText(String.format("%s meters", String.valueOf(
NumberFormat.getNumberInstance(Locale.US).format(distanceBetweenDeviceAndTarget))));
}
}
}
});
}
 
@SuppressWarnings( {"MissingPermission"})
private void enableLocationComponent(@NonNull Style loadedMapStyle) {
// Check if permissions are enabled and if not request
if (PermissionsManager.areLocationPermissionsGranted(this)) {
 
// Get an instance of the component
LocationComponent locationComponent = mapboxMap.getLocationComponent();
 
// Activate with options
locationComponent.activateLocationComponent(
LocationComponentActivationOptions.builder(this, loadedMapStyle).build());
 
// Enable to make component visible
locationComponent.setLocationComponentEnabled(true);
 
// Set the component's camera mode
locationComponent.setCameraMode(CameraMode.TRACKING);
 
// Set the component's render mode
locationComponent.setRenderMode(RenderMode.COMPASS);
} else {
permissionsManager = new PermissionsManager(this);
permissionsManager.requestLocationPermissions(this);
}
}
 
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
@NonNull int[] grantResults) {
permissionsManager.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
 
@Override
public void onExplanationNeeded(List<String> permissionsToExplain) {
Toast.makeText(this, R.string.user_location_permission_explanation,
Toast.LENGTH_LONG).show();
}
 
@Override
public void onPermissionResult(boolean granted) {
if (granted) {
mapboxMap.getStyle(new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
enableLocationComponent(style);
}
});
} else {
Toast.makeText(this, R.string.user_location_permission_not_granted, Toast.LENGTH_LONG).show();
finish();
}
}
 
// Add the mapView lifecycle to the activity's lifecycle methods
@Override
public void onResume() {
super.onResume();
mapView.onResume();
}
 
@Override
protected void onStart() {
super.onStart();
mapView.onStart();
}
 
@Override
protected void onStop() {
super.onStop();
mapView.onStop();
}
 
@Override
public void onPause() {
super.onPause();
mapView.onPause();
}
 
@Override
public void onLowMemory() {
super.onLowMemory();
mapView.onLowMemory();
}
 
@Override
protected void onDestroy() {
super.onDestroy();
if (mapboxMap != null) {
mapboxMap.removeOnCameraMoveListener(this);
}
mapView.onDestroy();
}
 
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mapView.onSaveInstanceState(outState);
}
}