Moveable POI within filter
Note
This example is a part of the Mapbox Android Demo app. You can find the values for all referenced resources in the res directory. For example, see res/values/activity_strings.xml for R.string.* references used in this example. The dependencies can be found here.The examples use View binding.See setup documention if necessary.
activity_lab_turf_circle_poi_within_filter
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:mapbox="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".examples.javaservices.TurfCirclePoiWithinFilterActivity">
<com.mapbox.mapboxsdk.maps.MapView
android:id="@+id/mapView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/guideline9"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
mapbox:mapbox_cameraTargetLat="48.1371079"
mapbox:mapbox_cameraTargetLng="11.5753822"/>
<androidx.constraintlayout.widget.Guideline
android:id="@+id/guideline9"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.80" />
<TextView
android:id="@+id/circle_radius_textview"
android:layout_width="0dp"
android:layout_height="27dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:gravity="center"
android:text="@string/polygon_circle_transformation_circle_radius"
android:textSize="20sp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="@+id/guideline9" />
<TextView
android:id="@+id/distance_units_textview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:gravity="center"
android:text="@string/polygon_circle_transformation_circle_distance_units"
android:textSize="20sp"
android:textStyle="bold"
mapbox:layout_constraintStart_toStartOf="parent"
mapbox:layout_constraintTop_toBottomOf="@+id/circle_radius_seekbar" />
<SeekBar
android:id="@+id/circle_radius_seekbar"
android:layout_width="395dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/circle_radius_textview" />
<Spinner
android:id="@+id/circle_units_spinner"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
app:layout_constraintBottom_toBottomOf="@+id/distance_units_textview"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/distance_units_textview"
app:layout_constraintTop_toTopOf="@+id/distance_units_textview" />
</androidx.constraintlayout.widget.ConstraintLayout>
TurfCirclePoiWithinFilterActivity.java
package com.mapbox.mapboxandroiddemo.examples.javaservices;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.SeekBar;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import com.mapbox.geojson.LineString;
import com.mapbox.geojson.Point;
import com.mapbox.geojson.Polygon;
import com.mapbox.mapboxandroiddemo.R;
import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.camera.CameraUpdateFactory;
import com.mapbox.mapboxsdk.geometry.LatLng;
import com.mapbox.mapboxsdk.geometry.LatLngBounds;
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.expressions.Expression;
import com.mapbox.mapboxsdk.style.layers.FillLayer;
import com.mapbox.mapboxsdk.style.layers.SymbolLayer;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import com.mapbox.turf.TurfMeta;
import com.mapbox.turf.TurfTransformation;
import java.util.ArrayList;
import java.util.List;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import static com.mapbox.mapboxsdk.camera.CameraUpdateFactory.newLatLngBounds;
import static com.mapbox.mapboxsdk.style.expressions.Expression.within;
import static com.mapbox.mapboxsdk.style.layers.Property.NONE;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.fillColor;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.fillOpacity;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.visibility;
import static com.mapbox.turf.TurfConstants.UNIT_KILOMETERS;
import static com.mapbox.turf.TurfConstants.UNIT_MILES;
/**
* Use {@link TurfTransformation#circle(Point, double, int, String)} to draw a
* circle at a center coordinate with its radius specified in physical units (i.e. "miles").
* The circle is actually a {@link Polygon} with 360 sides. More about information
* about {@link TurfTransformation} can be found at
* https://github.com/mapbox/mapbox-java/blob/ master/services-turf/src/main/java/
* com/mapbox/turf/TurfTransformation.java and at http://turfjs.org/docs/#circle.
* <p>
* Then use the {@link Expression#within(Polygon)} expression in a layer filter
* to only show POIs that are inside of the circular polygon area.
*/
public class TurfCirclePoiWithinFilterActivity extends AppCompatActivity implements MapboxMap.OnMapClickListener,
AdapterView.OnItemSelectedListener {
private static final String TAG = "FilterActivity";
private static final String TURF_CALCULATION_FILL_LAYER_GEOJSON_SOURCE_ID
= "TURF_CALCULATION_FILL_LAYER_GEOJSON_SOURCE_ID";
private static final String TURF_CALCULATION_FILL_LAYER_ID = "TURF_CALCULATION_FILL_LAYER_ID";
private static final int RADIUS_SEEKBAR_DIFFERENCE = 1;
private static final int RADIUS_SEEKBAR_MAX = 10;
private static final Point DOWNTOWN_MUNICH_START_LOCATION =
Point.fromLngLat(11.5753822, 48.1371079);
private Point lastClickPoint;
private MapView mapView;
private MapboxMap mapboxMap;
private String circleUnit = UNIT_KILOMETERS;
private int circleRadius = RADIUS_SEEKBAR_MAX / 2;
private TextView circleRadiusTextView;
@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_lab_turf_circle_poi_within_filter);
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(new OnMapReadyCallback() {
@Override
public void onMapReady(@NonNull MapboxMap mapboxMap) {
mapboxMap.setStyle(new Style.Builder().fromUri(Style.MAPBOX_STREETS)
.withSource(new GeoJsonSource(TURF_CALCULATION_FILL_LAYER_GEOJSON_SOURCE_ID)),
new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
TurfCirclePoiWithinFilterActivity.this.mapboxMap = mapboxMap;
hideLayers();
initPolygonCircleFillLayer();
// Set up the seekbar so that the circle's radius can be adjusted
final SeekBar circleRadiusSeekbar = findViewById(R.id.circle_radius_seekbar);
circleRadiusSeekbar.setMax(RADIUS_SEEKBAR_MAX);
circleRadiusSeekbar.incrementProgressBy(RADIUS_SEEKBAR_DIFFERENCE / 10);
circleRadiusSeekbar.setProgress(RADIUS_SEEKBAR_MAX / 2);
circleRadiusTextView = findViewById(R.id.circle_radius_textview);
circleRadiusTextView.setText(String.format(getString(
R.string.polygon_circle_transformation_circle_radius),
String.format(".%s", String.valueOf(RADIUS_SEEKBAR_MAX / 2))));
// Draw the initial circle around the starting location
drawPolygonCircle(DOWNTOWN_MUNICH_START_LOCATION);
circleRadiusSeekbar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
makeNewRadiusAdjustments(seekBar.getProgress());
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// Not needed in this example.
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
makeNewRadiusAdjustments(seekBar.getProgress());
}
});
mapboxMap.addOnMapClickListener(TurfCirclePoiWithinFilterActivity.this);
initDistanceUnitSpinner();
Toast.makeText(TurfCirclePoiWithinFilterActivity.this,
getString(R.string.polygon_circle_transformation_click_map_instruction),
Toast.LENGTH_SHORT).show();
}
});
}
});
}
/**
* Remove other types of label layers from the style in order to highlight the POI label layer.
*/
private void hideLayers() {
mapboxMap.getStyle(new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
SymbolLayer roadLabelLayer = style.getLayerAs("road-label");
if (roadLabelLayer != null) {
roadLabelLayer.setProperties(visibility(NONE));
}
SymbolLayer transitLabelLayer = style.getLayerAs("transit-label");
if (transitLabelLayer != null) {
transitLabelLayer.setProperties(visibility(NONE));
}
SymbolLayer roadNumberShieldLayer = style.getLayerAs("road-number-shield");
if (roadNumberShieldLayer != null) {
roadNumberShieldLayer.setProperties(visibility(NONE));
}
}
});
}
private void makeNewRadiusAdjustments(int progress) {
String amount;
if (progress == 0) {
amount = "0";
} else if (progress == RADIUS_SEEKBAR_MAX) {
amount = "1";
} else {
amount = String.format(".%s", String.valueOf(progress));
}
circleRadiusTextView.setText(String.format(getString(
R.string.polygon_circle_transformation_circle_radius), amount));
circleRadius = progress;
drawPolygonCircle(lastClickPoint != null ? lastClickPoint : DOWNTOWN_MUNICH_START_LOCATION);
}
private void initDistanceUnitSpinner() {
Spinner spinner = findViewById(R.id.circle_units_spinner);
spinner.setOnItemSelectedListener(this);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
R.array.within_poi_filter_circle_distance_units_array, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
}
@Override
public void onItemSelected(AdapterView<?> parentAdapterView, View view, int position, long id) {
String selectedUnitInSpinnerMenu = String.valueOf(parentAdapterView.getItemAtPosition(position));
if ("Miles".equals(selectedUnitInSpinnerMenu)) {
circleUnit = UNIT_MILES;
} else {
circleUnit = UNIT_KILOMETERS;
}
drawPolygonCircle(lastClickPoint != null ? lastClickPoint : DOWNTOWN_MUNICH_START_LOCATION);
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
// Empty on purpose. Not used in this example.
}
@Override
public boolean onMapClick(@NonNull LatLng mapClickLatLng) {
mapboxMap.easeCamera(CameraUpdateFactory.newLatLng(mapClickLatLng));
lastClickPoint = Point.fromLngLat(mapClickLatLng.getLongitude(), mapClickLatLng.getLatitude());
drawPolygonCircle(lastClickPoint);
return true;
}
/**
* Update the {@link FillLayer} based on the GeoJSON retrieved via
* {@link this#getTurfPolygon(Point, double, String)}.
*
* @param circleCenter the center coordinate to be used in the Turf calculation.
*/
private void drawPolygonCircle(Point circleCenter) {
mapboxMap.getStyle(new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
// Use Turf to calculate the Polygon's coordinates
Polygon polygonArea = getTurfPolygon(circleCenter, circleRadius, circleUnit);
List<Point> pointList = TurfMeta.coordAll(polygonArea, false);
// Update the source's GeoJSON to draw a new circle
GeoJsonSource polygonCircleSource = style.getSourceAs(TURF_CALCULATION_FILL_LAYER_GEOJSON_SOURCE_ID);
if (polygonCircleSource != null) {
polygonCircleSource.setGeoJson(Polygon.fromOuterInner(
LineString.fromLngLats(pointList)));
}
// Show new places of interest (POIs)
filterPlacesOfInterest(polygonArea);
// Adjust camera bounds to include entire circle
List<LatLng> latLngList = new ArrayList<>(pointList.size());
for (Point singlePoint : pointList) {
latLngList.add(new LatLng((singlePoint.latitude()), singlePoint.longitude()));
}
mapboxMap.easeCamera(newLatLngBounds(
new LatLngBounds.Builder()
.includes(latLngList)
.build(), 75), 1000);
}
});
}
/**
* Show only POI labels inside geometry using within expression
*
* @param polygonArea the polygon area (a circle in this example) to show POIs in.
*/
private void filterPlacesOfInterest(Polygon polygonArea) {
mapboxMap.getStyle(new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
SymbolLayer poiLabelLayer = style.getLayerAs("poi-label");
if (poiLabelLayer != null) {
poiLabelLayer.setFilter(within(polygonArea));
}
}
});
}
/**
* Use the Turf library {@link TurfTransformation#circle(Point, double, int, String)} method to
* retrieve a {@link Polygon} .
*
* @param centerPoint a {@link Point} which the circle will center around
* @param radius the radius of the circle
* @param units one of the units found inside {@link com.mapbox.turf.TurfConstants}
* @return a {@link Polygon} which represents the newly created circle
*/
private Polygon getTurfPolygon(@NonNull Point centerPoint, double radius,
@NonNull String units) {
return TurfTransformation.circle(centerPoint, radius / 10, 360, units);
}
/**
* Add a {@link FillLayer} to display a {@link Polygon} in a the shape of a circle.
*/
private void initPolygonCircleFillLayer() {
mapboxMap.getStyle(new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
// Create and style a FillLayer based on information that will come from the Turf calculation
FillLayer fillLayer = new FillLayer(TURF_CALCULATION_FILL_LAYER_ID,
TURF_CALCULATION_FILL_LAYER_GEOJSON_SOURCE_ID);
fillLayer.setProperties(
fillColor(Color.parseColor("#f5425d")),
fillOpacity(.5f));
style.addLayerBelow(fillLayer, "poi-label");
}
});
}
// Add the mapView lifecycle to the activity's lifecycle methods
@Override
protected void onStart() {
super.onStart();
mapView.onStart();
}
@Override
public void onResume() {
super.onResume();
mapView.onResume();
}
@Override
public void onPause() {
super.onPause();
mapView.onPause();
}
@Override
public void onLowMemory() {
super.onLowMemory();
mapView.onLowMemory();
}
@Override
protected void onStop() {
super.onStop();
mapView.onStop();
}
@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);
}
}
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