Identify features in all layers in a map.
Use case
"Identify layers" operation allows users to tap on a map, returning features at that location across multiple layers. Because some layer types have sublayers, the sample recursively counts results for sublayers within each layer.
How to use the sample
Tap to identify features. A bottom text banner will show all layers with features under the tapped location, as well as the number of features.
How it works
- The tapped position is passed to
MapView.identifyLayers(...)method. - For each
IdentifyLayerResultin the results, features are counted.- Note: there is one identify result per layer with matching features; if the feature count is 0, that means a sublayer contains the matching features.
Relevant API
- IdentifyLayerResult
- IdentifyLayerResult.sublayerResults
- LayerContent
Additional information
This sample uses the GeoViewCompose Toolkit module to be able to implement a Composable MapView. The GeoView supports two methods of identify: identifyLayer, which identifies features within a specific layer and identifyLayers, which identifies features for all layers in the current view.
Tags
geoviewcompose, identify, recursion, recursive, sublayers, toolkit
Sample Code
/* Copyright 2023 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.arcgismaps.sample.identifylayerfeatures
import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.runtime.Composable
import com.arcgismaps.ApiKey
import com.arcgismaps.ArcGISEnvironment
import com.esri.arcgismaps.sample.sampleslib.theme.SampleAppTheme
import com.esri.arcgismaps.sample.identifylayerfeatures.screens.MainScreen
class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
// authentication with an API key or named user is
// required to access basemaps and other location services
ArcGISEnvironment.apiKey = ApiKey.create(BuildConfig.API_KEY)
setContent {
SampleAppTheme {
IdentifyLayerFeaturesApp()
}
}
}
@Composable
private fun IdentifyLayerFeaturesApp() {
Surface(
color = MaterialTheme.colorScheme.background
) {
MainScreen(
sampleName = getString(R.string.app_name)
)
}
}
}