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Zoom to show a cluster's leaves

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This page uses v9.7.1 of the Mapbox Maps SDK. A newer version of the SDK is available. Learn about the latest version, v11.2.2, in the Maps SDK documentation.
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.

activity_zoom_to_show_cluster_leaves
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.mapbox.mapboxandroiddemo.examples.camera.ZoomToShowClusterLeavesActivity">

<com.mapbox.mapboxsdk.maps.MapView
android:id="@+id/mapView"
android:layout_width="match_parent"
android:layout_height="match_parent" />

</FrameLayout>
ZoomToShowClusterLeavesActivity.java
package com.mapbox.mapboxandroiddemo.examples.camera;

import android.graphics.Color;
import android.graphics.PointF;
import android.graphics.RectF;
import android.os.Bundle;
import android.widget.Toast;

import com.mapbox.geojson.Feature;
import com.mapbox.geojson.FeatureCollection;
import com.mapbox.geojson.Point;
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.CircleLayer;
import com.mapbox.mapboxsdk.style.layers.SymbolLayer;
import com.mapbox.mapboxsdk.style.layers.TransitionOptions;
import com.mapbox.mapboxsdk.style.sources.GeoJsonOptions;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import com.mapbox.mapboxsdk.utils.BitmapUtils;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import timber.log.Timber;

import static com.mapbox.mapboxsdk.style.expressions.Expression.all;
import static com.mapbox.mapboxsdk.style.expressions.Expression.division;
import static com.mapbox.mapboxsdk.style.expressions.Expression.get;
import static com.mapbox.mapboxsdk.style.expressions.Expression.gte;
import static com.mapbox.mapboxsdk.style.expressions.Expression.has;
import static com.mapbox.mapboxsdk.style.expressions.Expression.literal;
import static com.mapbox.mapboxsdk.style.expressions.Expression.lt;
import static com.mapbox.mapboxsdk.style.expressions.Expression.toNumber;
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.iconImage;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconSize;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.textAllowOverlap;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.textColor;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.textField;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.textIgnorePlacement;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.textSize;

/**
* Tap on a cluster and adjust the map camera bounds to fit that cluster's leaves.
*/
public class ZoomToShowClusterLeavesActivity extends AppCompatActivity implements MapboxMap.OnMapClickListener {

private MapView mapView;
private MapboxMap mapboxMap;
private GeoJsonSource geoJsonSource;
private String[] queryLayerIds;

@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_zoom_to_show_cluster_leaves);

mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(new OnMapReadyCallback() {
@Override
public void onMapReady(@NonNull MapboxMap map) {
map.setStyle(Style.DARK, new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {

mapboxMap = map;

// Disable any type of fading transition when icons collide on the map. This enhances the visual
// look of the data clustering together and breaking apart.
style.setTransition(new TransitionOptions(0, 0, false));

mapboxMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(12.099, -79.045), 3));

addClusteredGeoJsonSource(style);

style.addImage(
"icon-id",
BitmapUtils.getBitmapFromDrawable(getResources().getDrawable(R.drawable.single_quake_icon)));

mapboxMap.addOnMapClickListener(ZoomToShowClusterLeavesActivity.this);

Toast.makeText(ZoomToShowClusterLeavesActivity.this,
R.string.tap_on_cluster_circle_instruction, Toast.LENGTH_SHORT).show();
}
});
}
});
}

@Override
public boolean onMapClick(@NonNull LatLng point) {
PointF pointf = mapboxMap.getProjection().toScreenLocation(point);
RectF rectF = new RectF(pointf.x - 10, pointf.y - 10, pointf.x + 10, pointf.y + 10);
List<Feature> mapClickFeatureList = mapboxMap.queryRenderedFeatures(rectF, queryLayerIds);
if (mapClickFeatureList.size() > 0) {
FeatureCollection clusterLeavesFeatureCollection = geoJsonSource.getClusterLeaves(mapClickFeatureList.get(0),
8000, 0);
moveCameraToLeavesBounds(clusterLeavesFeatureCollection);
}

return true;
}

private void moveCameraToLeavesBounds(FeatureCollection featureCollectionToInspect) {
List<LatLng> latLngList = new ArrayList<>();
if (featureCollectionToInspect.features() != null) {
for (Feature singleClusterFeature : featureCollectionToInspect.features()) {
Point clusterPoint = (Point) singleClusterFeature.geometry();
if (clusterPoint != null) {
latLngList.add(new LatLng(clusterPoint.latitude(), clusterPoint.longitude()));
}
}
if (latLngList.size() > 1) {
LatLngBounds latLngBounds = new LatLngBounds.Builder()
.includes(latLngList)
.build();
mapboxMap.easeCamera(CameraUpdateFactory.newLatLngBounds(latLngBounds, 230),
1300);
}
}
}

private void addClusteredGeoJsonSource(@NonNull Style loadedMapStyle) {

// Add a new source from the GeoJSON data and set the "cluster" option to true.
try {

// Point to GeoJSON data. This example visualizes all M1.0+ earthquakes from
// 12/22/15 to 1/21/16 as logged by USGS' Earthquake hazards program.
geoJsonSource = new GeoJsonSource("earthquakes",
new URI("https://www.mapbox.com/mapbox-gl-js/assets/earthquakes.geojson"),
new GeoJsonOptions()
.withCluster(true)
.withClusterMaxZoom(14)
.withClusterRadius(50)
);
loadedMapStyle.addSource(

geoJsonSource
);
} catch (URISyntaxException uriSyntaxException) {
Timber.e("Check the URL %s", uriSyntaxException.getMessage());
}

// Creating a marker layer for single data points
SymbolLayer unclustered = new SymbolLayer("unclustered-points", "earthquakes");

unclustered.setProperties(
iconImage("icon-id"),
iconSize(
division(
get("mag"), literal(4.0f)
)
)
);
unclustered.setFilter(has("mag"));
loadedMapStyle.addLayer(unclustered);

// Use the earthquakes GeoJSON source to create three layers: One layer for each cluster category.
// Each point range gets a different fill color.
int[][] layers = new int[][] {
new int[] {150, ContextCompat.getColor(this, R.color.mapboxPurple)},
new int[] {20, ContextCompat.getColor(this, R.color.mapboxOrange)},
new int[] {0, ContextCompat.getColor(this, R.color.mapboxPinkDark)}
};

queryLayerIds = new String[layers.length];

for (int i = 0; i < layers.length; i++) {
queryLayerIds[i] = "cluster-" + i;
// Add clusters' circles
CircleLayer circles = new CircleLayer(queryLayerIds[i], "earthquakes");
circles.setProperties(
circleColor(layers[i][1]),
circleRadius(18f)
);

Expression pointCount = toNumber(get("point_count"));

// Add a filter to the cluster layer that hides the circles based on "point_count"
circles.setFilter(
i == 0
? all(has("point_count"),
gte(pointCount, literal(layers[i][0]))
) : all(has("point_count"),
gte(pointCount, literal(layers[i][0])),
lt(pointCount, literal(layers[i - 1][0]))
)
);
loadedMapStyle.addLayer(circles);
}

// Add the count labels
SymbolLayer count = new SymbolLayer("count", "earthquakes");
count.setProperties(
textField(Expression.toString(get("point_count"))),
textSize(12f),
textColor(Color.WHITE),
textIgnorePlacement(true),
textAllowOverlap(true)
);
loadedMapStyle.addLayer(count);
}

@Override
public 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 onStop() {
super.onStop();
mapView.onStop();
}

@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);
}
}