Query a map feature
A newer version of the Maps SDK is available
This page uses v9.7.1 of the Mapbox Maps SDK. A newer version of the SDK is available. Learn about the latest version, v11.8.0, 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. The dependencies can be found here.The examples use View binding.See setup documention if necessary.
activity_query_feature
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
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.query.QueryFeatureActivity">
<com.mapbox.mapboxsdk.maps.MapView
android:id="@+id/mapView"
android:layout_width="match_parent"
android:layout_height="match_parent"
mapbox:mapbox_cameraTargetLat="29.7565"
mapbox:mapbox_cameraTargetLng="-95.3625"
mapbox:mapbox_cameraZoom="16"/>
</FrameLayout>
QueryFeatureActivity.java
package com.mapbox.mapboxandroiddemo.examples.query;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.PointF;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import com.google.gson.JsonElement;
import com.mapbox.geojson.Feature;
import com.mapbox.geojson.FeatureCollection;
import com.mapbox.mapboxandroiddemo.R;
import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.annotations.BubbleLayout;
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.SymbolLayer;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import static com.mapbox.mapboxsdk.style.layers.Property.ICON_ANCHOR_BOTTOM;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconAllowOverlap;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconAnchor;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconIgnorePlacement;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconImage;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconOffset;
/**
* Display map property information for a clicked map feature.
*/
public class QueryFeatureActivity extends AppCompatActivity implements OnMapReadyCallback,
MapboxMap.OnMapClickListener {
private static final String GEOJSON_SOURCE_ID = "GEOJSON_SOURCE_ID";
private static final String MARKER_IMAGE_ID = "MARKER_IMAGE_ID";
private static final String CALLOUT_IMAGE_ID = "CALLOUT_IMAGE_ID";
private static final String MARKER_LAYER_ID = "MARKER_LAYER_ID";
private static final String CALLOUT_LAYER_ID = "CALLOUT_LAYER_ID";
private GeoJsonSource source;
private MapView mapView;
private MapboxMap mapboxMap;
@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_query_feature);
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(this);
}
@Override
public void onMapReady(@NonNull final MapboxMap mapboxMap) {
QueryFeatureActivity.this.mapboxMap = mapboxMap;
mapboxMap.setStyle(Style.MAPBOX_STREETS, new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
setUpData();
mapboxMap.addOnMapClickListener(QueryFeatureActivity.this);
Toast.makeText(QueryFeatureActivity.this,
getString(R.string.click_on_map_instruction), Toast.LENGTH_SHORT).show();
}
});
}
/**
* Sets up all of the sources and layers needed for this example
*/
public void setUpData() {
if (mapboxMap != null) {
mapboxMap.getStyle(style -> {
setupSource(style);
setUpClickLocationIconImage(style);
setUpClickLocationMarkerLayer(style);
setUpInfoWindowLayer(style);
});
}
}
/**
* Adds the GeoJSON source to the map
*/
private void setupSource(@NonNull Style loadedStyle) {
source = new GeoJsonSource(GEOJSON_SOURCE_ID);
loadedStyle.addSource(source);
}
/**
* Adds the marker image to the map for use as a SymbolLayer icon
*/
private void setUpClickLocationIconImage(@NonNull Style loadedStyle) {
loadedStyle.addImage(MARKER_IMAGE_ID, BitmapFactory.decodeResource(
this.getResources(), R.drawable.red_marker));
}
/**
* Needed to show the Feature properties info window.
*/
private void refreshSource(Feature featureAtClickPoint) {
if (source != null) {
source.setGeoJson(featureAtClickPoint);
}
}
/**
* Adds a SymbolLayer to the map to show the click location marker icon.
*/
private void setUpClickLocationMarkerLayer(@NonNull Style loadedStyle) {
loadedStyle.addLayer(new SymbolLayer(MARKER_LAYER_ID, GEOJSON_SOURCE_ID)
.withProperties(
iconImage(MARKER_IMAGE_ID),
iconAllowOverlap(true),
iconIgnorePlacement(true),
iconOffset(new Float[] {0f, -8f})
));
}
/**
* Adds a SymbolLayer to the map to show the Feature properties info window.
*/
private void setUpInfoWindowLayer(@NonNull Style loadedStyle) {
loadedStyle.addLayer(new SymbolLayer(CALLOUT_LAYER_ID, GEOJSON_SOURCE_ID)
.withProperties(
// show image with id title based on the value of the name feature property
iconImage(CALLOUT_IMAGE_ID),
// set anchor of icon to bottom-left
iconAnchor(ICON_ANCHOR_BOTTOM),
// prevent the feature property window icon from being visible even
// if it collides with other previously drawn symbols
iconAllowOverlap(false),
// prevent other symbols from being visible even if they collide with the feature property window icon
iconIgnorePlacement(false),
// offset the info window to be above the marker
iconOffset(new Float[] {-2f, -28f})
));
}
/**
* This method handles click events for SymbolLayer symbols.
*
* @param screenPoint the point on screen clicked
*/
private boolean handleClickIcon(PointF screenPoint) {
List<Feature> features = mapboxMap.queryRenderedFeatures(screenPoint);
if (!features.isEmpty()) {
Feature feature = features.get(0);
StringBuilder stringBuilder = new StringBuilder();
if (feature.properties() != null) {
for (Map.Entry<String, JsonElement> entry : feature.properties().entrySet()) {
stringBuilder.append(String.format("%s - %s", entry.getKey(), entry.getValue()));
stringBuilder.append(System.getProperty("line.separator"));
}
new GenerateViewIconTask(QueryFeatureActivity.this).execute(FeatureCollection.fromFeature(feature));
}
} else {
Toast.makeText(this, getString(R.string.query_feature_no_properties_found), Toast.LENGTH_SHORT).show();
}
return true;
}
@Override
public boolean onMapClick(@NonNull LatLng point) {
return handleClickIcon(mapboxMap.getProjection().toScreenLocation(point));
}
/**
* Invoked when the bitmap has been generated from a view.
*/
public void setImageGenResults(HashMap<String, Bitmap> imageMap) {
if (mapboxMap != null) {
mapboxMap.getStyle(style -> {
style.addImages(imageMap);
});
}
}
/**
* AsyncTask to generate Bitmap from Views to be used as iconImage in a SymbolLayer.
* <p>
* Call be optionally be called to update the underlying data source after execution.
* </p>
* <p>
* Generating Views on background thread since we are not going to be adding them to the view hierarchy.
* </p>
*/
private static class GenerateViewIconTask extends AsyncTask<FeatureCollection, Void, HashMap<String, Bitmap>> {
private final WeakReference<QueryFeatureActivity> activityRef;
private Feature featureAtMapClickPoint;
GenerateViewIconTask(QueryFeatureActivity activity) {
this.activityRef = new WeakReference<>(activity);
}
@SuppressWarnings("WrongThread")
@Override
protected HashMap<String, Bitmap> doInBackground(FeatureCollection... params) {
QueryFeatureActivity activity = activityRef.get();
HashMap<String, Bitmap> imagesMap = new HashMap<>();
if (activity != null) {
LayoutInflater inflater = LayoutInflater.from(activity);
if (params[0].features() != null) {
featureAtMapClickPoint = params[0].features().get(0);
StringBuilder stringBuilder = new StringBuilder();
BubbleLayout bubbleLayout = (BubbleLayout) inflater.inflate(
R.layout.activity_query_feature_window_symbol_layer, null);
TextView titleTextView = bubbleLayout.findViewById(R.id.info_window_title);
titleTextView.setText(activity.getString(R.string.query_feature_marker_title));
if (featureAtMapClickPoint.properties() != null) {
for (Map.Entry<String, JsonElement> entry : featureAtMapClickPoint.properties().entrySet()) {
stringBuilder.append(String.format("%s - %s", entry.getKey(), entry.getValue()));
stringBuilder.append(System.getProperty("line.separator"));
}
TextView propertiesListTextView = bubbleLayout.findViewById(R.id.info_window_feature_properties_list);
propertiesListTextView.setText(stringBuilder.toString());
int measureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
bubbleLayout.measure(measureSpec, measureSpec);
float measuredWidth = bubbleLayout.getMeasuredWidth();
bubbleLayout.setArrowPosition(measuredWidth / 2 - 5);
Bitmap bitmap = QueryFeatureActivity.SymbolGenerator.generate(bubbleLayout);
imagesMap.put(CALLOUT_IMAGE_ID, bitmap);
}
}
}
return imagesMap;
}
@Override
protected void onPostExecute(HashMap<String, Bitmap> bitmapHashMap) {
super.onPostExecute(bitmapHashMap);
QueryFeatureActivity activity = activityRef.get();
if (activity != null && bitmapHashMap != null) {
activity.setImageGenResults(bitmapHashMap);
activity.refreshSource(featureAtMapClickPoint);
}
}
}
/**
* Utility class to generate Bitmaps for Symbol.
*/
private static class SymbolGenerator {
/**
* Generate a Bitmap from an Android SDK View.
*
* @param view the View to be drawn to a Bitmap
* @return the generated bitmap
*/
static Bitmap generate(@NonNull View view) {
int measureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
view.measure(measureSpec, measureSpec);
int measuredWidth = view.getMeasuredWidth();
int measuredHeight = view.getMeasuredHeight();
view.layout(0, 0, measuredWidth, measuredHeight);
Bitmap bitmap = Bitmap.createBitmap(measuredWidth, measuredHeight, Bitmap.Config.ARGB_8888);
bitmap.eraseColor(Color.TRANSPARENT);
Canvas canvas = new Canvas(bitmap);
view.draw(canvas);
return bitmap;
}
}
@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);
}
}