Feature layer selection

View inJavaKotlin
View on GitHub
Sample viewer app

Select features in a feature layer.

Image of feature layer selection

Use case

Selecting features, whether by query or identify, can be an important step both in editing data and visualizing results. One possible use case would be to query a feature layer containing street furniture. A query might look for type "bench" and return a list of bench features contained in the features with an attribute of type bench. These might be selected for further editing (see FeatureQueryResult) or may just be highlighted visually.

How to use the sample

Tap on a feature in the map. All features within a given tolerance (in pixels) of the tap will be selected.

How it works

  1. Create a ServiceFeatureTable from a feature service URL.
  2. Create a FeatureLayer from the service feature table.
  3. Identify nearby features at the clicked location using identifyLayerAsync(featureLayer, clickLocation, tolerance, returnPopupsOnly, maxResults) on the map view.
  4. Select all identified features in the feature layer with selectFeaturesAsync(query, FeatureLayer.SelectionMode.NEW).

Relevant API

  • Feature
  • FeatureLayer
  • ServiceFeatureTable

About the data

This sample uses the Gross Domestic Product, 1960-2016 feature service. Only the 2016 GDP values are shown.

Tags

features, layers, select, selection, tolerance

Sample Code

MainActivity.kt
Use dark colors for code blocksCopy
                                                                                                                                               
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/*
 * Copyright 2020 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.featurelayerselection

import android.graphics.Color
import android.os.Bundle
import android.util.Log
import android.view.MotionEvent
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.esri.arcgisruntime.ArcGISRuntimeEnvironment
import com.esri.arcgisruntime.data.Feature
import com.esri.arcgisruntime.data.ServiceFeatureTable
import com.esri.arcgisruntime.geometry.Envelope
import com.esri.arcgisruntime.geometry.SpatialReferences
import com.esri.arcgisruntime.layers.FeatureLayer
import com.esri.arcgisruntime.mapping.ArcGISMap
import com.esri.arcgisruntime.mapping.BasemapStyle
import com.esri.arcgisruntime.mapping.Viewpoint
import com.esri.arcgisruntime.mapping.view.DefaultMapViewOnTouchListener
import com.esri.arcgisruntime.mapping.view.MapView
import com.esri.arcgisruntime.sample.featurelayerselection.databinding.ActivityMainBinding
import kotlin.math.roundToInt

class MainActivity : AppCompatActivity() {

    private val TAG: String = MainActivity::class.java.simpleName

    private val activityMainBinding by lazy {
        ActivityMainBinding.inflate(layoutInflater)
    }

    private val mapView: MapView by lazy {
        activityMainBinding.mapView
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(activityMainBinding.root)

        // authentication with an API key or named user is required to access basemaps and other
        // location services
        ArcGISRuntimeEnvironment.setApiKey(BuildConfig.API_KEY)

        // create service feature table and a feature layer from it
        val serviceFeatureTable = ServiceFeatureTable(getString(R.string.gdp_per_capita_url))
        val featureLayer = FeatureLayer(serviceFeatureTable)

        // create a map with the streets base map type
        val streetsMap = ArcGISMap(BasemapStyle.ARCGIS_STREETS).apply {
            // add the feature layer to the map's operational layers
            operationalLayers.add(featureLayer)
        }

        mapView.let {
            // set the map to be displayed in the layout's map view
            it.map = streetsMap
            // set an initial view point
            it.setViewpoint(
                Viewpoint(
                    Envelope(
                        -1131596.019761,
                        3893114.069099,
                        3926705.982140,
                        7977912.461790,
                        SpatialReferences.getWebMercator()
                    )
                )
            )
            // give any item selected on the map view a red selection halo
            it.selectionProperties.color = Color.RED
            // set an on touch listener on the map view
            it.onTouchListener = object : DefaultMapViewOnTouchListener(this, it) {
                override fun onSingleTapConfirmed(motionEvent: MotionEvent): Boolean {
                    // clear the previous selection
                    featureLayer.clearSelection()
                    // get the point that was tapped and convert it to a point in map coordinates
                    val tappedPoint =
                        android.graphics.Point(
                            motionEvent.x.roundToInt(),
                            motionEvent.y.roundToInt()
                        )
                    // set a tolerance for accuracy of returned selections from point tapped
                    val tolerance = 25.0

                    val identifyLayerResultFuture =
                        mapView.identifyLayerAsync(featureLayer, tappedPoint, tolerance, false, -1)
                    identifyLayerResultFuture.addDoneListener {
                        try {
                            val identifyLayerResult = identifyLayerResultFuture.get()
                            // get the elements in the selection that are features
                            val features = identifyLayerResult.elements.filterIsInstance<Feature>()
                            // add the features to the current feature layer selection
                            featureLayer.selectFeatures(features)
                            // make a toast to show the number of features selected
                            Toast.makeText(
                                applicationContext,
                                "${features.size} features selected",
                                Toast.LENGTH_SHORT
                            ).show()
                        } catch (e: Exception) {
                            val errorMessage = "Select feature failed: " + e.message
                            Log.e(TAG, errorMessage)
                            Toast.makeText(applicationContext, errorMessage, Toast.LENGTH_LONG)
                                .show()
                        }
                    }
                    return super.onSingleTapConfirmed(motionEvent)
                }
            }
        }
    }

    override fun onResume() {
        super.onResume()
        mapView.resume()
    }

    override fun onPause() {
        mapView.pause()
        super.onPause()
    }

    override fun onDestroy() {
        mapView.dispose()
        super.onDestroy()
    }
}

Your browser is no longer supported. Please upgrade your browser for the best experience. See our browser deprecation post for more details.