Measure line distance

package com.mapbox.mapboxandroiddemo.examples.javaservices;
 
import android.graphics.Color;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;
 
import com.mapbox.geojson.Feature;
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.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.CircleLayer;
import com.mapbox.mapboxsdk.style.layers.LineLayer;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import com.mapbox.turf.TurfMeasurement;
 
import java.util.ArrayList;
import java.util.List;
 
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.circleColor;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.circleRadius;
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_KILOMETERS;
 
/**
* Use {@link com.mapbox.turf.TurfMeasurement#distance(Point, Point)} to measure the distance of a drawn line.
*/
public class TurfLineDistanceActivity extends AppCompatActivity implements MapboxMap.OnMapClickListener {
 
private static final String SOURCE_ID = "SOURCE_ID";
private static final String CIRCLE_LAYER_ID = "CIRCLE_LAYER_ID";
private static final String LINE_LAYER_ID = "LINE_LAYER_ID";
 
// Adjust private static final variables below to change the example's UI
private static final String STYLE_URI = "mapbox://styles/mapbox/cjv6rzz4j3m4b1fqcchuxclhb";
private static final int CIRCLE_COLOR = Color.RED;
private static final int LINE_COLOR = CIRCLE_COLOR;
private static final float CIRCLE_RADIUS = 6f;
private static final float LINE_WIDTH = 4f;
private static final String DISTANCE_UNITS = UNIT_KILOMETERS; // DISTANCE_UNITS must be equal to a String
// found in the TurfConstants class
 
private List<Point> pointList = new ArrayList<>();
private MapView mapView;
private MapboxMap mapboxMap;
private TextView lineLengthTextView;
private double totalLineDistance = 0;
 
@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_turf_measure_line);
 
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
 
mapView.getMapAsync(new OnMapReadyCallback() {
@Override
public void onMapReady(@NonNull MapboxMap mapboxMap) {
 
lineLengthTextView = findViewById(R.id.line_length_textView);
 
// DISTANCE_UNITS must be equal to a String found in the TurfConstants class
lineLengthTextView.setText(String.format(getString(R.string.line_distance_textview),
DISTANCE_UNITS, String.valueOf(totalLineDistance)));
 
TurfLineDistanceActivity.this.mapboxMap = mapboxMap;
mapboxMap.setStyle(new Style.Builder()
.fromUri(STYLE_URI)
 
// Add the source to the map
.withSource(new GeoJsonSource(SOURCE_ID))
 
// Style and add the CircleLayer to the map
.withLayer(new CircleLayer(CIRCLE_LAYER_ID, SOURCE_ID).withProperties(
circleColor(CIRCLE_COLOR),
circleRadius(CIRCLE_RADIUS)
))
 
// Style and add the LineLayer to the map. The LineLayer is placed below the CircleLayer.
.withLayerBelow(new LineLayer(LINE_LAYER_ID, SOURCE_ID).withProperties(
lineColor(LINE_COLOR),
lineWidth(LINE_WIDTH),
lineJoin(LINE_JOIN_ROUND)
), CIRCLE_LAYER_ID), new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
TurfLineDistanceActivity.this.mapboxMap.addOnMapClickListener(TurfLineDistanceActivity.this);
Toast.makeText(TurfLineDistanceActivity.this, getString(
R.string.line_distance_tap_instruction), Toast.LENGTH_SHORT).show();
}
}
);
}
});
}
 
@Override
public boolean onMapClick(@NonNull LatLng point) {
addClickPointToLine(point);
return true;
}
 
/**
* Handle the map click location and re-draw the circle and line data.
*
* @param clickLatLng where the map was tapped on.
*/
private void addClickPointToLine(@NonNull LatLng clickLatLng) {
mapboxMap.getStyle(new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
// Get the source from the map's style
GeoJsonSource geoJsonSource = style.getSourceAs(SOURCE_ID);
if (geoJsonSource != null) {
 
pointList.add(Point.fromLngLat(clickLatLng.getLongitude(), clickLatLng.getLatitude()));
 
int pointListSize = pointList.size();
 
double distanceBetweenLastAndSecondToLastClickPoint = 0;
 
// Make the Turf calculation between the last tap point and the second-to-last tap point.
if (pointList.size() >= 2) {
distanceBetweenLastAndSecondToLastClickPoint = TurfMeasurement.distance(
pointList.get(pointListSize - 2), pointList.get(pointListSize - 1));
}
 
// Re-draw the new GeoJSON data
if (pointListSize >= 2 && distanceBetweenLastAndSecondToLastClickPoint > 0) {
 
// Add the last TurfMeasurement#distance calculated distance to the total line distance.
totalLineDistance += distanceBetweenLastAndSecondToLastClickPoint;
 
// Adjust the TextView to display the new total line distance.
// DISTANCE_UNITS must be equal to a String found in the TurfConstants class
lineLengthTextView.setText(String.format(getString(R.string.line_distance_textview), DISTANCE_UNITS,
String.valueOf(totalLineDistance)));
 
// Set the specific source's GeoJSON data
geoJsonSource.setGeoJson(Feature.fromGeometry(LineString.fromLngLats(pointList)));
}
}
}
});
}
 
// 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.removeOnMapClickListener(this);
}
mapView.onDestroy();
}
 
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mapView.onSaveInstanceState(outState);
}
}