Display a feature layer from a service using the manual cache feature request mode.
Use case
Service feature tables support three request modes, which define how features are requested from the service and stored in the local table. The feature request modes have different performance characteristics. Use manual cache in scenarios where you want to explicitly control requests for features.
How to use the sample
Run the sample and pan and zoom around the map. Features will be requested and displayed automatically.
How it works
Set the ServiceFeatureTable.setFeatureRequestMode(...) property of the service feature table to MANUAL_CACHE before the table is loaded.
Load the table with serviceFeatureTable.loadAsync().
Call populateFromServiceAsync() on the table to request features.
Relevant API
FeatureLayer
FeatureRequestMode.MANUAL_CACHE
ServiceFeatureTable
ServiceFeatureTable.populateFromServiceAsync
ServiceFeatureTable.setFeatureRequestMode
About the data
The sample opens with a tree maintenance feature layer centered over San Francisco.
Additional information
In manual cache mode, features are never automatically populated from the service. All features are loaded manually using calls to populateFromServiceAsync.
Tags
cache, feature request mode, performance
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.samples.servicefeaturetablemanualcache;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;
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.FeatureQueryResult;
import com.esri.arcgisruntime.data.QueryParameters;
import com.esri.arcgisruntime.data.ServiceFeatureTable;
import com.esri.arcgisruntime.geometry.Point;
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.MapView;
publicclassMainActivityextendsAppCompatActivity{
private MapView mMapView;
@OverrideprotectedvoidonCreate(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 a map with the topographic basemap ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_TOPOGRAPHIC);
// create feature layer with its service feature table// create the service feature tablefinal ServiceFeatureTable serviceFeatureTable = new ServiceFeatureTable(
getResources().getString(R.string.sample_service_url));
//explicitly set the mode to on manual cache (which means you need to call populate from service) serviceFeatureTable.setFeatureRequestMode(ServiceFeatureTable.FeatureRequestMode.MANUAL_CACHE);
// create the feature layer using the service feature table FeatureLayer featureLayer = new FeatureLayer(serviceFeatureTable);
// add the layer to the map map.getOperationalLayers().add(featureLayer);
// load the table serviceFeatureTable.loadAsync();
// add a done loading listener to call populate from service when the table is loaded is done serviceFeatureTable.addDoneLoadingListener(new Runnable() {
@Overridepublicvoidrun(){
// set up the query parameters QueryParameters params = new QueryParameters();
// for a specific 311 request type params.setWhereClause("req_type = 'Tree Maintenance or Damage'");
// set all outfields List<String> outFields = new ArrayList<>();
outFields.add("*");
//populate the table based on the query, listen for result in a listenable futurefinal ListenableFuture<FeatureQueryResult> future = serviceFeatureTable
.populateFromServiceAsync(params, true, outFields);
//add done listener to the future which fires when the async method is complete future.addDoneListener(new Runnable() {
@Overridepublicvoidrun(){
try {
//call get on the future to get the result FeatureQueryResult result = future.get();
// create an Iterator Iterator<Feature> iterator = result.iterator();
Feature feature;
// cycle through selectionsint counter = 0;
while (iterator.hasNext()) {
feature = iterator.next();
counter++;
Log.d(getResources().getString(R.string.app_name),
"Selection #: " + counter + " Table name: " + feature.getFeatureTable().getTableName());
}
Toast.makeText(getApplicationContext(), counter + " features returned", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Log.e(getResources().getString(R.string.app_name), "Populate from service failed: " + e.getMessage());
}
}
});
}
});
// set the map to be displayed in the mapview mMapView.setMap(map);
//set a viewpoint on the mapview so it zooms to the features once they are cached. mMapView.setViewpoint(new Viewpoint(new Point(-13630484, 4545415, SpatialReferences.getWebMercator()), 500000));
}
@OverrideprotectedvoidonPause(){
super.onPause();
// pause MapView mMapView.pause();
}
@OverrideprotectedvoidonResume(){
super.onResume();
// resume MapView mMapView.resume();
}
@OverrideprotectedvoidonDestroy(){
super.onDestroy();
// dispose MapView mMapView.dispose();
}
}