Custom Polygon Cluster

This example shows how to add Polygon Cluster in MapView

Add Cluster from GeoJson
Aggregate a large number of coordinate points

For all code examples, refer to Android Maps SDK Code Examples

activity_polygon_cluster.xml view source

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<?xml version="1.0" encoding="utf-8"?>
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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
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    xmlns:app="http://schemas.android.com/apk/res-auto"
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    xmlns:tools="http://schemas.android.com/tools"
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    android:layout_width="match_parent"
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    android:layout_height="match_parent"
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    android:orientation="vertical"
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    tools:context=".PolygonActivity">
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    <ai.nextbillion.maps.core.MapView
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        android:id="@id/map_view"
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        android:layout_width="match_parent"
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        android:layout_height="match_parent"
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        app:nbmap_uiAttribution="false"
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        app:nbmap_cameraTargetLat="1.3383500934590808"
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        app:nbmap_cameraTargetLng="103.80586766146754"
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        app:nbmap_cameraZoom="11" />
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    <com.google.android.material.floatingactionbutton.FloatingActionButton
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        android:id="@+id/fab_route"
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        android:layout_width="wrap_content"
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        android:layout_height="wrap_content"
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        android:layout_alignParentBottom="true"
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        android:layout_alignParentEnd="true"
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        android:layout_alignParentRight="true"
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        android:layout_marginBottom="@dimen/fab_margin"
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        android:layout_marginRight="@dimen/fab_margin"
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        android:layout_marginEnd="@dimen/fab_margin"
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        android:src="@drawable/ic_directions_bus_black"
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        app:backgroundTint="@android:color/white" />
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    <com.google.android.material.floatingactionbutton.FloatingActionButton
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        android:id="@+id/fab_style"
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        android:layout_width="wrap_content"
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        android:layout_height="wrap_content"
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        android:layout_above="@id/fab_route"
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        android:layout_alignParentEnd="true"
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        android:layout_alignParentRight="true"
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        android:layout_marginBottom="@dimen/fab_margin"
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        android:layout_marginRight="@dimen/fab_margin"
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        android:src="@drawable/ic_layers"
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        android:layout_marginEnd="@dimen/fab_margin"
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        app:backgroundTint="@color/purple_200"
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        android:visibility="gone"/>
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    <ImageView
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        android:id="@+id/back_ib"
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        android:layout_width="40dp"
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        android:layout_height="40dp"
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        android:layout_marginLeft="12dp"
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        android:layout_marginTop="30dp"
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        android:background="@drawable/circle_white_bg"
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        android:src="@drawable/icon_back"
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        app:tint="@color/color_back_icon"/>
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</RelativeLayout>

PolygonClusterActivity view source

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public class PolygonClusterActivity extends AppCompatActivity implements OnMapReadyCallback, NextbillionMap.OnMapClickListener, View.OnClickListener {
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   private static final String TAG = "PolygonClusterActivity";
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   public static final String SOURCE_ID = "bus_stop";
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   public static final String SOURCE_ID_CLUSTER = "bus_stop_cluster";
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   public static final String URL_BUS_ROUTES = "https://raw.githubusercontent.com/cheeaun/busrouter-sg/master/data/2/bus-stops.geojson";
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   public static final String LAYER_ID = "stops_layer";
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   private static final String TAXI = "taxi";
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   private ImageView backBtn;
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   private MapView mapView;
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   private NextbillionMap nextbillionMap;
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   private FloatingActionButton styleFab;
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   private FloatingActionButton routeFab;
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   private CircleLayer layer;
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   private GeoJsonSource source;
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   private int currentStyleIndex = 0;
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   private boolean isLoadingStyle = true;
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   @Override
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   protected void onCreate(Bundle savedInstanceState) {
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       super.onCreate(savedInstanceState);
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       setContentView(R.layout.activity_polygon_cluster);
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       mapView = findViewById(R.id.map_view);
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       backBtn = findViewById(R.id.back_ib);
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       mapView.onCreate(savedInstanceState);
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       mapView.getMapAsync(this);
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       backBtn.setOnClickListener(new View.OnClickListener() {
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           @Override
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           public void onClick(View v) {
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               finish();
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           }
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       });
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   }
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   @Override
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   public void onMapReady(@NonNull NextbillionMap nbMap) {
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       this.nextbillionMap = nbMap;
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       mapView.addOnDidFinishLoadingStyleListener(() -> {
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           Style style = nextbillionMap.getStyle();
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           style.addImage(TAXI,(BitmapDrawable)getResources().getDrawable(R.mipmap.beat_taxi));
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           addBusStopSource(style);
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           addBusStopCircleLayer(style);
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           initFloatingActionButtons();
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           isLoadingStyle = false;
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       });
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   }
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   @Override
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   public boolean onMapClick(@NonNull LatLng latLng) {
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       return false;
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   }
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   private void addBusStopSource(Style style) {
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       try {
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           source = new GeoJsonSource(SOURCE_ID, new URI(URL_BUS_ROUTES));
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       } catch (URISyntaxException exception) {
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           Log.e(TAG, "That's not an url... ");
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       }
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       style.addSource(source);
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   }
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   private void addBusStopCircleLayer(Style style) {
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       layer = new CircleLayer(LAYER_ID, SOURCE_ID);
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       layer.setProperties(
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               circleColor(Color.parseColor("#FF0000")),
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               circleRadius(2.0f)
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       );
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       style.addLayerBelow(layer, "waterway-label");
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   }
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   private void initFloatingActionButtons() {
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       routeFab = findViewById(R.id.fab_route);
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       routeFab.setColorFilter(ContextCompat.getColor(PolygonClusterActivity.this, R.color.purple_200));
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       routeFab.setOnClickListener(PolygonClusterActivity.this);
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       styleFab = findViewById(R.id.fab_style);
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       styleFab.setOnClickListener(PolygonClusterActivity.this);
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   }
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   @Override
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   public void onClick(View view) {
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       if (isLoadingStyle) {
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           return;
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       }
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       if (view.getId() == R.id.fab_route) {
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           showBusCluster();
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       } else if (view.getId() == R.id.fab_style) {
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           changeMapStyle();
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       }
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   }
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   private void showBusCluster() {
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       removeFabs();
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       removeOldSource();
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       addClusteredSource();
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   }
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   private void removeOldSource() {
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       nextbillionMap.getStyle().removeSource(SOURCE_ID);
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       nextbillionMap.getStyle().removeLayer(LAYER_ID);
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   }
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   private void addClusteredSource() {
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       try {
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           nextbillionMap.getStyle().addSource(
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                   new GeoJsonSource(SOURCE_ID_CLUSTER,
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                           new URI(URL_BUS_ROUTES),
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                           new GeoJsonOptions()
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                                   .withCluster(true)
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                                   .withClusterMaxZoom(14)
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                                   .withClusterRadius(50)
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                   )
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           );
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       } catch (URISyntaxException malformedUrlException) {
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           Log.e(TAG, "That's not an url... ");
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       }
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       // Add unclustered layer
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       int[][] layers = new int[][]{
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               new int[]{150, ResourcesCompat.getColor(getResources(), R.color.purple_200, getTheme())},
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               new int[]{20, ResourcesCompat.getColor(getResources(), R.color.colorAccent, getTheme())},
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               new int[]{0, ResourcesCompat.getColor(getResources(), R.color.color_4158ce, getTheme())}
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       };
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       SymbolLayer unclustered = new SymbolLayer("unclustered-points", SOURCE_ID_CLUSTER);
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       unclustered.setProperties(
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               iconImage(TAXI)
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       );
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       nextbillionMap.getStyle().addLayer(unclustered);
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       for (int i = 0; i < layers.length; i++) {
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           // Add some nice circles
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           CircleLayer circles = new CircleLayer("cluster-" + i, SOURCE_ID_CLUSTER);
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           circles.setProperties(
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                   circleColor(layers[i][1]),
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                   circleRadius(18f)
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           );
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           Expression pointCount = toNumber(get("point_count"));
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           circles.setFilter(
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                   i == 0
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                           ? all(has("point_count"),
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                           gte(pointCount, literal(layers[i][0]))
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                   ) : all(has("point_count"),
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                           gt(pointCount, literal(layers[i][0])),
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                           lt(pointCount, literal(layers[i - 1][0]))
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                   )
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           );
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           nextbillionMap.getStyle().addLayer(circles);
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       }
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       // Add the count labels
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       SymbolLayer count = new SymbolLayer("count", SOURCE_ID_CLUSTER);
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       count.setProperties(
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               textField(Expression.toString(get("point_count"))),
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               textSize(12f),
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               textColor(Color.WHITE),
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               textIgnorePlacement(true),
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               textAllowOverlap(true)
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       );
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       nextbillionMap.getStyle().addLayer(count);
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   }
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   private void removeFabs() {
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       routeFab.setVisibility(View.GONE);
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       styleFab.setVisibility(View.GONE);
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   }
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   private void changeMapStyle() {
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       isLoadingStyle = true;
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       removeBusStop();
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       loadNewStyle();
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   }
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   private void removeBusStop() {
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       nextbillionMap.getStyle().removeLayer(layer);
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       nextbillionMap.getStyle().removeSource(source);
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   }
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   private void loadNewStyle() {
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       nextbillionMap.setStyle(new Style.Builder().fromUri(getNextStyle()));
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   }
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   private void addBusStop() {
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       nextbillionMap.getStyle().addLayer(layer);
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       nextbillionMap.getStyle().addSource(source);
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   }
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   private String getNextStyle() {
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       currentStyleIndex++;
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       if (currentStyleIndex == Data.STYLES.length) {
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           currentStyleIndex = 0;
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       }
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       return Data.STYLES[currentStyleIndex];
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   }
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   ///////////////////////////////////////////////////////////////////////////
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   // Lifecycle
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   ///////////////////////////////////////////////////////////////////////////
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   @Override
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   protected void onStart() {
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       super.onStart();
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       mapView.onStart();
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   }
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   @Override
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   protected void onResume() {
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       super.onResume();
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       mapView.onResume();
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   }
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   @Override
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   protected void onPause() {
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       super.onPause();
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       mapView.onPause();
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   }
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   @Override
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   protected void onStop() {
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       super.onStop();
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       mapView.onStop();
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   }
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   @Override
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   protected void onSaveInstanceState(@NonNull Bundle outState) {
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       super.onSaveInstanceState(outState);
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       mapView.onSaveInstanceState(outState);
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   }
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   @Override
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   protected void onDestroy() {
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       super.onDestroy();
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       mapView.onDestroy();
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   }
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   @Override
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   public void onLowMemory() {
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       super.onLowMemory();
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       mapView.onLowMemory();
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   }
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   private static class Data {
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       private static final String[] STYLES = new String[]{
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               Style.NBMAP_STREETS,
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               Style.OUTDOORS,
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               Style.LIGHT,
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               Style.DARK,
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               Style.SATELLITE,
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               Style.SATELLITE_STREETS
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       };
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   }
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}

onMapReady: This method is called when the map is ready to be used. It initializes the NextbillionMap object and adds listeners to the map-style loading event. Once the style finishes loading, it adds the bus stop source, bus stop circle layer and sets up the floating action buttons.
addBusStopSource: This method adds a GeoJsonSource to the map style, representing the bus stop data source. It creates a GeoJsonSource object with the provided URL to a GeoJSON file containing bus stop information and adds it to the map style.
addBusStopCircleLayer: This method adds a CircleLayer to the map style, representing the bus stop markers on the map. It creates a CircleLayer object with the specified layer ID and source ID, sets properties for the circle color and radius and adds the layer to the map style.
addClusteredSource: This method adds a clustered source to the map style, representing a clustering of bus stops. It creates a GeoJsonSource object with the provided URL to a GeoJSON file, enables clustering with specified cluster options and adds the source to the map style. It also adds clustered and unclustered layers to represent the clusters and individual bus stops on the map.
showBusCluster: This method is called when the user clicks on the "Route" floating action button. It removes the existing floating action buttons, removes the old bus stop source and layer from the map style, and adds a clustered source with clustered and unclustered layers to represent the bus stop clusters on the map.