Feature layer show attributes
Return all loaded features from a query to show all attributes.
Use case
Attributes can be used to help describe the objects represented by a feature. A geologist might use an attribute to describe the rock type of polygons representing surface geology. Archaeologists might use attributes to record the stratigraphic layer of finds represented as point features.
How to use the sample
Tap on a feature to see its attributes in a callout.
How it works
- Create an instance of a
ServiceFeatureTable
. - Identify selected features with
mMapView.identifyLayerAsync(...)
and pass in the feature layer and tapped location to get all of the attributes for the feature at that location. - Get the
IdentifyLayerResult
and iterate through the results to display each attribute in a callout.
Relevant API
- Feature
- FeatureLayer
- FeatureQueryResult
- ServiceFeatureTable
Tags
features, layers, query, attributes
Sample Code
MainActivity.java
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/*
* Copyright 2016 Esri
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package com.esri.arcgisruntime.sample.featurelayershowattributes;
import java.text.SimpleDateFormat;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import android.graphics.Color;
import android.graphics.Point;
import android.os.Bundle;
import android.text.method.ScrollingMovementMethod;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.concurrent.ListenableFuture;
import com.esri.arcgisruntime.data.Feature;
import com.esri.arcgisruntime.data.ServiceFeatureTable;
import com.esri.arcgisruntime.geometry.Envelope;
import com.esri.arcgisruntime.layers.FeatureLayer;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.GeoElement;
import com.esri.arcgisruntime.mapping.Viewpoint;
import com.esri.arcgisruntime.mapping.view.Callout;
import com.esri.arcgisruntime.mapping.view.DefaultMapViewOnTouchListener;
import com.esri.arcgisruntime.mapping.view.IdentifyLayerResult;
import com.esri.arcgisruntime.mapping.view.MapView;
public class MainActivity extends AppCompatActivity {
private MapView mMapView;
private Callout mCallout;
private ServiceFeatureTable mServiceFeatureTable;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// authentication with an API key or named user is required to access basemaps and other
// location services
ArcGISRuntimeEnvironment.setApiKey(BuildConfig.API_KEY);
// inflate MapView from layout
mMapView = findViewById(R.id.mapView);
// create an ArcGISMap with a topographic basemap
final ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_TOPOGRAPHIC);
// set the ArcGISMap to the MapView
mMapView.setMap(map);
// set a viewpoint
mMapView.setViewpoint(new Viewpoint(34.057386, -117.191455, 100000000));
// get the callout that shows attributes
mCallout = mMapView.getCallout();
// create the service feature table
mServiceFeatureTable = new ServiceFeatureTable(getResources().getString(R.string.sample_service_url));
// create the feature layer using the service feature table
final FeatureLayer featureLayer = new FeatureLayer(mServiceFeatureTable);
// add the layer to the map
map.getOperationalLayers().add(featureLayer);
// set an on touch listener to listen for click events
mMapView.setOnTouchListener(new DefaultMapViewOnTouchListener(this, mMapView) {
@Override
public boolean onSingleTapConfirmed(MotionEvent e) {
// remove any existing callouts
if (mCallout.isShowing()) {
mCallout.dismiss();
}
// get the point that was clicked and convert it to a point in map coordinates
final Point screenPoint = new Point(Math.round(e.getX()), Math.round(e.getY()));
// create a selection tolerance
int tolerance = 10;
// use identifyLayerAsync to get tapped features
final ListenableFuture<IdentifyLayerResult> identifyLayerResultListenableFuture = mMapView
.identifyLayerAsync(featureLayer, screenPoint, tolerance, false, 1);
identifyLayerResultListenableFuture.addDoneListener(() -> {
try {
IdentifyLayerResult identifyLayerResult = identifyLayerResultListenableFuture.get();
// create a textview to display field values
TextView calloutContent = new TextView(getApplicationContext());
calloutContent.setTextColor(Color.BLACK);
calloutContent.setSingleLine(false);
calloutContent.setVerticalScrollBarEnabled(true);
calloutContent.setScrollBarStyle(View.SCROLLBARS_INSIDE_INSET);
calloutContent.setMovementMethod(new ScrollingMovementMethod());
calloutContent.setLines(5);
for (GeoElement element : identifyLayerResult.getElements()) {
Feature feature = (Feature) element;
// create a map of all available attributes as name value pairs
Map<String, Object> attr = feature.getAttributes();
Set<String> keys = attr.keySet();
for (String key : keys) {
Object value = attr.get(key);
// format observed field value as date
if (value instanceof GregorianCalendar) {
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MMM-yyyy", Locale.US);
value = simpleDateFormat.format(((GregorianCalendar) value).getTime());
}
// append name value pairs to text view
calloutContent.append(key + " | " + value + "\n");
}
// center the mapview on selected feature
Envelope envelope = feature.getGeometry().getExtent();
mMapView.setViewpointGeometryAsync(envelope, 200);
// show callout
mCallout.setLocation(envelope.getCenter());
mCallout.setContent(calloutContent);
mCallout.show();
}
} catch (Exception e1) {
Log.e(getResources().getString(R.string.app_name), "Select feature failed: " + e1.getMessage());
}
});
return super.onSingleTapConfirmed(e);
}
});
}
@Override
protected void onPause() {
super.onPause();
mMapView.pause();
}
@Override
protected void onResume() {
super.onResume();
mMapView.resume();
}
@Override
protected void onDestroy() {
super.onDestroy();
mMapView.dispose();
}
}