Service feature table (cache)

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Sample viewer app

Display a feature layer from a service using the on interaction cache feature request mode.

screenshot

Use case

ServiceFeatureTable supports 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 On interaction cache in scenarios with large amounts of infrequently edited data.

How to use the sample

Run the sample and pan and zoom around the map. With each interaction, features will be requested and stored in a local cache. Each subsequent interaction will display features from the cache and only request new features from the service.

How it works

Create a ServiceFeatureTable with the provided URL.
Since the default request mode is FeatureRequestMode::OnInteractionCache we do not need to change it.
Add the table to the map using a FeatureLayer.

Relevant API

FeatureLayer
FeatureRequestMode::OnInteractionCache
ServiceFeatureTable
ServiceFeatureTable::setFeatureRequestMode

About the data

This sample displays a Pool permit feature layer in Riverside, California, displaying which parcels do not have pool permits.

Additional information

On interaction cache is the default feature request mode. Features are requested automatically for the visible extent as the users pans and zooms the map. If the user returns to an area where features have previously been requested, those features won't be requested again.

Sample Code

ServiceFeatureTableCache.cpp

ServiceFeatureTableCache.h

ServiceFeatureTableCache.qml

Use dark colors for code blocksCopy
// [WriteFile Name=ServiceFeatureTableCache, Category=Features]
// [Legal]
// 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.
// [Legal]

#ifdef PCH_BUILD
#include "pch.hpp"
#endif // PCH_BUILD

#include "ServiceFeatureTableCache.h"

#include "Map.h"
#include "MapQuickView.h"
#include "FeatureLayer.h"
#include "Basemap.h"
#include "SpatialReference.h"
#include "ServiceFeatureTable.h"
#include "Viewpoint.h"
#include "Envelope.h"
#include "MapViewTypes.h"
#include "MapTypes.h"
#include "LayerListModel.h"
#include <QUrl>

using namespace Esri::ArcGISRuntime;

ServiceFeatureTableCache::ServiceFeatureTableCache(QQuickItem* parent) :
  QQuickItem(parent)
{
}

ServiceFeatureTableCache::~ServiceFeatureTableCache() = default;

void ServiceFeatureTableCache::init()
{
  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");
  qmlRegisterType<ServiceFeatureTableCache>("Esri.Samples", 1, 0, "ServiceFeatureTableCacheSample");
}

void ServiceFeatureTableCache::componentComplete()
{
  QQuickItem::componentComplete();

  // find QML MapView component
  m_mapView = findChild<MapQuickView*>("mapView");
  m_mapView->setWrapAroundMode(WrapAroundMode::Disabled);

  // Create a map using the light gray canvas basemap
  m_map = new Map(BasemapStyle::ArcGISLightGray, this);
  m_map->setInitialViewpoint(Viewpoint(Envelope(-13075816.4047166, 4014771.46954516, -13073005.6797177, 4016869.78617381, SpatialReference(102100))));

  // Set map to map view
  m_mapView->setMap(m_map);

  // create the feature table
  m_featureTable = new ServiceFeatureTable(QUrl("https://sampleserver6.arcgisonline.com/arcgis/rest/services/PoolPermits/FeatureServer/0"), this);

  // create the feature layer using the feature table
  m_featureLayer = new FeatureLayer(m_featureTable, this);

  // add the feature layer to the map
  m_map->operationalLayers()->append(m_featureLayer);
}