Identify layer features

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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 /* 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.components  import android.app.Application import androidx.compose.runtime.mutableStateOf import androidx.compose.ui.unit.dp import androidx.lifecycle.AndroidViewModel import com.arcgismaps.data.ServiceFeatureTable import com.arcgismaps.mapping.ArcGISMap import com.arcgismaps.mapping.BasemapStyle import com.arcgismaps.mapping.Viewpoint import com.arcgismaps.mapping.layers.ArcGISMapImageLayer import com.arcgismaps.mapping.layers.FeatureLayer.Companion.createWithFeatureTable import com.arcgismaps.mapping.view.IdentifyLayerResult import com.arcgismaps.mapping.view.SingleTapConfirmedEvent import com.arcgismaps.toolkit.geoviewcompose.MapViewProxy import com.esri.arcgismaps.sample.identifylayerfeatures.R import com.esri.arcgismaps.sample.sampleslib.components.MessageDialogViewModel import kotlinx.coroutines.CoroutineScope import kotlinx.coroutines.launch  class MapViewModel(  application: Application,  private val sampleCoroutineScope: CoroutineScope ) : AndroidViewModel(application) {   // create a map using the topographic basemap style  val map: ArcGISMap = ArcGISMap(BasemapStyle.ArcGISTopographic)   // create a mapViewProxy that will be used to identify features in the MapView  // should also be passed to the composable MapView this mapViewProxy is associated with  val mapViewProxy = MapViewProxy()   // create a ViewModel to handle dialog interactions  val messageDialogVM: MessageDialogViewModel = MessageDialogViewModel()   // string text to display the identify layer results  val bottomTextBanner = mutableStateOf("Tap on the map to identify feature layers")   init {  // create a feature layer of damaged property data  val featureTable = ServiceFeatureTable(application.getString(R.string.damage_assessment))  val featureLayer = createWithFeatureTable(featureTable)   // create a layer with world cities data  val mapImageLayer = ArcGISMapImageLayer(application.getString(R.string.world_cities))  sampleCoroutineScope.launch {  mapImageLayer.load().onSuccess {  mapImageLayer.apply {  subLayerContents.value[1].isVisible = false  subLayerContents.value[2].isVisible = false  }  }.onFailure { error ->  // show the message dialog and pass the error message to be displayed in the dialog  messageDialogVM.showMessageDialog(error.message.toString(), error.cause.toString())  }  }   // add the world cities layer with and the damaged properties feature layer  map.apply {  // set initial Viewpoint to North America  initialViewpoint = Viewpoint(39.8, -98.6, 5e7)  operationalLayers.addAll(listOf(mapImageLayer, featureLayer))  }   }   /**  * Identify the feature layer results and display the resulting information  */  private fun handleIdentifyResult(result: Result<List<IdentifyLayerResult>>) {  sampleCoroutineScope.launch {  result.onSuccess { identifyResultList ->  val message = StringBuilder()  var totalCount = 0  identifyResultList.forEach { identifyLayerResult ->  val geoElementsCount = geoElementsCountFromResult(identifyLayerResult)  val layerName = identifyLayerResult.layerContent.name  message.append(layerName).append(": ").append(geoElementsCount)   // add new line character if not the final element in array  if (identifyLayerResult != identifyResultList[identifyResultList.size - 1]) {  message.append("\n")  }  totalCount += geoElementsCount  }  // if any elements were found show the results, else notify user that no elements were found  if (totalCount > 0) {  bottomTextBanner.value = "Number of elements found:\n${message}"  } else {  bottomTextBanner.value = "Number of elements found: N/A"  messageDialogVM.showMessageDialog(  title = "No element found",  description = "Tap an area on the map with visible features"  )  }  }.onFailure { error ->  messageDialogVM.showMessageDialog(  title = "Error identifying results: ${error.message.toString()}",  description = error.cause.toString()  )  }  }  }   /**  * Gets a count of the GeoElements in the passed result layer.  * This method recursively calls itself to descend into sublayers and count their results.  * @param result from a single layer.  * @return the total count of GeoElements.  */  private fun geoElementsCountFromResult(result: IdentifyLayerResult): Int {  var subLayerGeoElementCount = 0  for (sublayerResult in result.sublayerResults) {  // recursively call this function to accumulate elements from all sublayers  subLayerGeoElementCount += geoElementsCountFromResult(sublayerResult)  }  return subLayerGeoElementCount + result.geoElements.size  }   /**  * Identifies the tapped screen coordinate in the provided [singleTapConfirmedEvent]  */  fun identify(singleTapConfirmedEvent: SingleTapConfirmedEvent) {  sampleCoroutineScope.launch {  // identify the layers on the tapped coordinate  val identifyResult = mapViewProxy.identifyLayers(  screenCoordinate = singleTapConfirmedEvent.screenCoordinate,  tolerance = 12.dp,  maximumResults = 10  )  // use the layer result to display feature information  handleIdentifyResult(identifyResult)  }  } }