List related features | ArcGIS Maps SDK for Qt

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Sample viewer app

List features related to a selected feature.

Use case

Related features are useful for managing relational information, like what you would store in a relational database management system (RDBMS). You can define relationship between records as one-to-one, one-to-many, or many-to-one. For example, you could model inspections and facilities as a many-to-one relationship. Then, for any facility feature, you could list related inspection features.

How to use the sample

Click on a feature to select it. The related features will be displayed in a list.

How it works

With a Feature, call queryRelatedFeaturesAsync on the feature’s feature table.
Iterate over the result’s collection of RelatedFeatureQueryResult objects to get the related features and add them to a list.

Relevant API

ArcGISFeature
ArcGISFeatureTable
FeatureQueryResult
ArcGISFeatureTable::queryRelatedFeaturesAsync
RelatedFeatureQueryResult

Sample Code

ListRelatedFeatures.cpp

ListRelatedFeatures.h

ListRelatedFeatures.qml

RelatedFeature.cpp

RelatedFeature.h

RelatedFeatureListModel.cpp

RelatedFeatureListModel.h

main.cpp

// [WriteFile Name=ListRelatedFeatures, Category=Features]
// [Legal]
// Copyright 2017 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

// sample headers
#include "ListRelatedFeatures.h"
#include "RelatedFeature.h"
#include "RelatedFeatureListModel.h"

// ArcGIS Maps SDK headers
#include "ArcGISFeature.h"
#include "ArcGISFeatureLayerInfo.h"
#include "ArcGISFeatureTable.h"
#include "AttributeListModel.h"
#include "CoreTypes.h"
#include "Envelope.h"
#include "Error.h"
#include "FeatureIterator.h"
#include "FeatureLayer.h"
#include "FeatureQueryResult.h"
#include "LayerListModel.h"
#include "Map.h"
#include "MapQuickView.h"
#include "MapTypes.h"
#include "Point.h"
#include "QueryParameters.h"
#include "RelatedFeatureQueryResult.h"
#include "SelectionProperties.h"
#include "SpatialReference.h"
#include "ViewInsets.h"

// Qt headers
#include <QFuture>
#include <QList>
#include <QUrl>
#include <QUuid>

// STL headers
#include <memory>

using namespace Esri::ArcGISRuntime;

namespace
{
  // Convenience RAII struct that deletes all pointers in given container.
  struct FeatureQueryListResultLock
  {
    FeatureQueryListResultLock(const QList<RelatedFeatureQueryResult*>& list) : results(list) { }
    ~FeatureQueryListResultLock() { qDeleteAll(results); }
    const QList<RelatedFeatureQueryResult*>& results;
  };
}

ListRelatedFeatures::ListRelatedFeatures(QQuickItem* parent /* = nullptr */):
  QQuickItem(parent)
{
}

void ListRelatedFeatures::init()
{
  // Register the map view for QML
  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");
  qmlRegisterType<ListRelatedFeatures>("Esri.Samples", 1, 0, "ListRelatedFeaturesSample");
  qmlRegisterAnonymousType<ViewInsets>("Esri.Samples", 1);
  qmlRegisterUncreatableType<RelatedFeatureListModel>("Esri.ArcGISRuntimeSamples", 1, 0,
                                                      "RelatedFeatureListModel", "RelatedFeatureListModel is an uncreatable type");
}

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

  // Create a list model to store the related features
  m_relatedFeaturesModel = new RelatedFeatureListModel(this);
  emit relatedFeaturesModelChanged();

  // find QML MapView component
  m_mapView = findChild<MapQuickView*>("mapView");
  m_mapView->setSelectionProperties(SelectionProperties(QColor(Qt::yellow)));

  // Create a map using the URL of a web map
  m_map = new Map(QUrl("https://arcgis.com/home/item.html?id=dcc7466a91294c0ab8f7a094430ab437"), this);

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

  // connect signals
  connectSignals();
}

void ListRelatedFeatures::connectSignals()
{
  // connect to doneLoading signal
  connect(m_map, &Map::doneLoading, this, [this](const Error& loadError)
  {
    if (!loadError.isEmpty())
      return;

    bool foundLayer = false; // Found the Alaska National Parks layer.
    for (int i = 0; i < m_map->operationalLayers()->size() || !foundLayer; ++i)
    {
      // get the Alaska National Parks layer
      if (m_map->operationalLayers()->at(i)->name().contains(QStringLiteral("- Alaska National Parks")))
      {
        foundLayer = true;
        m_alaskaNationalParks = static_cast<FeatureLayer*>(m_map->operationalLayers()->at(i));
        m_alaskaFeatureTable = static_cast<ArcGISFeatureTable*>(m_alaskaNationalParks->featureTable());
      }
    }
  });

  // connect to the mouseClicked signal
  connect(m_mapView, &MapQuickView::mouseClicked, this, [this](QMouseEvent& mouseEvent)
  {
    // hide the attribute view
    emit hideAttributeTable();

    // clear the list model
    m_relatedFeaturesModel->clear();

    // create objects required to do a selection with a query
    Point clickPoint = m_mapView->screenToLocation(mouseEvent.position().x(), mouseEvent.position().y());
    double mapTolerance = 10 * m_mapView->unitsPerDIP();
    Envelope envelope = Envelope(clickPoint.x() - mapTolerance,
                                 clickPoint.y() - mapTolerance,
                                 clickPoint.x() + mapTolerance,
                                 clickPoint.y() + mapTolerance,
                                 m_map->spatialReference());
    QueryParameters queryParams;
    queryParams.setGeometry(envelope);
    queryParams.setSpatialRelationship(SpatialRelationship::Intersects);

    // clear any selections
    m_alaskaNationalParks->clearSelection();

    // select features
    m_alaskaNationalParks->selectFeaturesAsync(queryParams, SelectionMode::New).then(this, [this](FeatureQueryResult* rawResult)
    {
      auto result = std::unique_ptr<FeatureQueryResult>(rawResult);
      // The result could contain more than 1 feature, but we assume that
      // there is only ever 1. If more are given they are ignored. We
      // are only interested in the first (and only) feature.
      if (result->iterator().hasNext())
      {
        m_selectedFeature = static_cast<ArcGISFeature*>(result->iterator().next(this));

        // zoom to the selected feature
        m_mapView->setViewpointGeometryAsync(m_selectedFeature->geometry().extent(), 100);

        // query related features
        m_alaskaFeatureTable->queryRelatedFeaturesAsync(m_selectedFeature).then(this, [this](QList<RelatedFeatureQueryResult*> rawRelatedResults)
        {
          FeatureQueryListResultLock lock(rawRelatedResults);
          for (const RelatedFeatureQueryResult* relatedResult : lock.results)
          {
            while (relatedResult->iterator().hasNext())
            {
              // get the related feature
              const ArcGISFeature* feature = static_cast<ArcGISFeature*>(relatedResult->iterator().next());
              const ArcGISFeatureTable* relatedTable = static_cast<ArcGISFeatureTable*>(feature->featureTable());
              const QString displayFieldName = relatedTable->layerInfo().displayFieldName();
              const QString serviceLayerName = relatedTable->layerInfo().serviceLayerName();
              const QString displayFieldValue = feature->attributes()->attributeValue(displayFieldName).toString();

              // add the related feature to the list model
              RelatedFeature relatedFeature = RelatedFeature(displayFieldName,
                                                             displayFieldValue,
                                                             serviceLayerName);
              m_relatedFeaturesModel->addRelatedFeature(relatedFeature);
              emit relatedFeaturesModelChanged();
            }
          }

          if (m_selectedFeature)
          {
            delete m_selectedFeature;
            m_selectedFeature = nullptr;
          }

          emit showAttributeTable();
        });
      }
    });
  });
}

QAbstractListModel* ListRelatedFeatures::relatedFeaturesModel() const
{
  return m_relatedFeaturesModel;
}

// [WriteFile Name=ListRelatedFeatures, Category=Features]
// [Legal]
// Copyright 2017 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]

#ifndef LISTRELATEDFEATURES_H
#define LISTRELATEDFEATURES_H

// Qt headers
#include <QQuickItem>

namespace Esri::ArcGISRuntime
{
  class ArcGISFeature;
  class ArcGISFeatureTable;
  class FeatureLayer;
  class Map;
  class MapQuickView;
}
class RelatedFeatureListModel;
class QAbstractListModel;

Q_MOC_INCLUDE("QAbstractListModel")

class ListRelatedFeatures : public QQuickItem
{
  Q_OBJECT

  Q_PROPERTY(QAbstractListModel* relatedFeaturesModel READ relatedFeaturesModel NOTIFY relatedFeaturesModelChanged)

public:
  explicit ListRelatedFeatures(QQuickItem* parent = nullptr);
  ~ListRelatedFeatures() override = default;

  void componentComplete() override;
  static void init();

signals:
  void showAttributeTable();
  void hideAttributeTable();
  void relatedFeaturesModelChanged();

private:
  void connectSignals();
  QAbstractListModel* relatedFeaturesModel() const;

  Esri::ArcGISRuntime::Map* m_map = nullptr;
  Esri::ArcGISRuntime::MapQuickView* m_mapView = nullptr;
  Esri::ArcGISRuntime::FeatureLayer* m_alaskaNationalParks = nullptr;
  Esri::ArcGISRuntime::ArcGISFeatureTable* m_alaskaFeatureTable = nullptr;
  Esri::ArcGISRuntime::ArcGISFeature* m_selectedFeature = nullptr;
  RelatedFeatureListModel* m_relatedFeaturesModel = nullptr;
};

#endif // LISTRELATEDFEATURES_H

// [WriteFile Name=ListRelatedFeatures, Category=Features]
// [Legal]
// Copyright 2017 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]

import QtQuick
import QtQuick.Controls
import Esri.Samples

ListRelatedFeaturesSample {
    id: rootRectangle
    clip: true
    width: 800
    height: 600

    onHideAttributeTable: attributeView.height = 0;
    onShowAttributeTable: attributeView.height = 200;

    MapView {
        id: mapView
        anchors.fill: parent
        objectName: "mapView"

        Component.onCompleted: {
            // Set the focus on MapView to initially enable keyboard navigation
            forceActiveFocus();
        }

        // bind the insets to the attribute view so the attribution text shows when the view expands
        viewInsets.bottom: attributeView.height
    }

    Rectangle {
        id: attributeView
        anchors {
            left: parent.left
            right: parent.right
            bottom: parent.bottom
        }
        height: 0

        // Animate the expand and collapse of the legend
        Behavior on height {
            SpringAnimation {
                spring: 3
                damping: 0.4
            }
        }

        ListView {
            anchors {
                fill: parent
                margins: 5
            }

            clip: true
            model: relatedFeaturesModel
            spacing: 5

            // Create delegate to display the attributes
            delegate: Rectangle {
                width: rootRectangle.width
                height: childrenRect.height
                color: "transparent"

                Text {
                    anchors.horizontalCenter: parent.horizontalCenter
                    anchors.margins: 10

                    text: displayFieldValue
                    font.pixelSize: 12
                }
            }

            // Create a section to separate features by table
            section {
                property: "serviceLayerName"
                criteria: ViewSection.FullString
                labelPositioning: ViewSection.CurrentLabelAtStart | ViewSection.InlineLabels
                delegate: Rectangle {
                    width: rootRectangle.width
                    height: childrenRect.height
                    color: "lightsteelblue"

                    Text {
                        anchors.horizontalCenter: parent.horizontalCenter
                        text: section
                        font {
                            bold: true
                            pixelSize: 13
                        }
                    }
                }
            }
        }
    }
}

// [WriteFile Name=ListRelatedFeatures, Category=Features]
// [Legal]
// Copyright 2017 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

// sample headers
#include "RelatedFeature.h"

// Qt headers
#include <QString>

RelatedFeature::RelatedFeature(const QString& displayFieldName, const QString& displayFieldValue,
                               const QString& serviceLayerName) :
  m_displayFieldName(displayFieldName),
  m_displayFieldValue(displayFieldValue),
  m_serviceLayerName(serviceLayerName)
{
}

// [WriteFile Name=ListRelatedFeatures, Category=Features]
// [Legal]
// Copyright 2017 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]

#ifndef RELATEDFEATURE_H
#define RELATEDFEATURE_H

// Qt headers
#include <QString>

class RelatedFeature
{

public:
  explicit RelatedFeature(const QString& displayFieldName, const QString& displayFieldValue,
                          const QString& serviceLayerName);
  ~RelatedFeature() = default;

public:
  QString displayFieldName() const { return m_displayFieldName; }
  QString displayFieldValue() const { return m_displayFieldValue; }
  QString serviceLayerName() const { return m_serviceLayerName; }

private:
  QString m_displayFieldName;
  QString m_displayFieldValue;
  QString m_serviceLayerName;
};

#endif // RELATEDFEATURE_H

// [WriteFile Name=ListRelatedFeatures, Category=Features]
// [Legal]
// Copyright 2017 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

// sample headers
#include "RelatedFeature.h"
#include "RelatedFeatureListModel.h"

// Qt headers
#include <QAbstractListModel>
#include <QByteArray>
#include <QHash>
#include <QModelIndex>
#include <QObject>
#include <QVariant>

RelatedFeatureListModel::RelatedFeatureListModel(QObject* parent) :
  QAbstractListModel(parent)
{
}

void RelatedFeatureListModel::addRelatedFeature(RelatedFeature relatedFeature)
{
  beginInsertRows(QModelIndex(), rowCount(), rowCount());
  m_relatedFeatures << relatedFeature;
  endInsertRows();
}
int RelatedFeatureListModel::rowCount(const QModelIndex& parent) const
{
  Q_UNUSED(parent);
  return m_relatedFeatures.count();
}

QVariant RelatedFeatureListModel::data(const QModelIndex& index, int role) const
{
  if (index.row() < 0 || index.row() >= m_relatedFeatures.count())
    return QVariant();

  RelatedFeature relatedFeature = m_relatedFeatures[index.row()];

  if (role == DisplayFieldNameRole)
    return relatedFeature.displayFieldName();
  else if (role == DisplayFieldValueRole)
    return relatedFeature.displayFieldValue();
  else if (role == ServiceLayerName)
    return relatedFeature.serviceLayerName();
  return QVariant();
}

QHash<int, QByteArray> RelatedFeatureListModel::roleNames() const
{
  QHash<int, QByteArray> roles;
  roles[DisplayFieldNameRole] = "displayFieldName";
  roles[DisplayFieldValueRole] = "displayFieldValue";
  roles[ServiceLayerName] = "serviceLayerName";
  return roles;
}

void RelatedFeatureListModel::clear()
{
  beginResetModel();
  m_relatedFeatures.clear();
  endResetModel();
}

// [WriteFile Name=ListRelatedFeatures, Category=Features]
// [Legal]
// Copyright 2017 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]

#ifndef RELATEDFEATURELISTMODEL_H
#define RELATEDFEATURELISTMODEL_H

// sample headers
#include "RelatedFeature.h"

// Qt headers
#include <QAbstractListModel>
#include <QByteArray>
#include <QHash>
#include <QList>

class RelatedFeatureListModel : public QAbstractListModel
{
  Q_OBJECT

public:
  enum RelatedRoles
  {
    DisplayFieldNameRole = Qt::UserRole + 1,
    DisplayFieldValueRole,
    ServiceLayerName
  };

  explicit RelatedFeatureListModel(QObject* parent = nullptr);
  ~RelatedFeatureListModel() override = default;

  void addRelatedFeature(RelatedFeature relatedFeature);
  int rowCount(const QModelIndex& parent = QModelIndex()) const override;
  QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;
  void clear();
  int size() const { return m_relatedFeatures.size(); }

protected:
  QHash<int, QByteArray> roleNames() const override;

private:
  QList<RelatedFeature> m_relatedFeatures;
};

#endif // RELATEDFEATURELISTMODEL_H

// [Legal]
// Copyright 2017 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]

// sample headers
#include "ListRelatedFeatures.h"

// ArcGIS Maps SDK headers
#include "ArcGISRuntimeEnvironment.h"

// Qt headers
#include <QCommandLineParser>
#include <QDir>
#include <QGuiApplication>
#include <QQmlEngine>
#include <QQuickView>

// Platform specific headers
#ifdef Q_OS_WIN
#include <Windows.h>
#endif

#define STRINGIZE(x) #x
#define QUOTE(x) STRINGIZE(x)

int main(int argc, char *argv[])
{
  Esri::ArcGISRuntime::ArcGISRuntimeEnvironment::setUseLegacyAuthentication(false);
  QGuiApplication app(argc, argv);
  app.setApplicationName(QString("ListRelatedFeatures"));

  // Use of ArcGIS location services, such as basemap styles, geocoding, and routing services,
  // requires an access token. For more information see
  // https://links.esri.com/arcgis-runtime-security-auth.

  // The following methods grant an access token:

  // 1. User authentication: Grants a temporary access token associated with a user's ArcGIS account.
  // To generate a token, a user logs in to the app with an ArcGIS account that is part of an
  // organization in ArcGIS Online or ArcGIS Enterprise.

  // 2. API key authentication: Get a long-lived access token that gives your application access to
  // ArcGIS location services. Go to the tutorial at https://links.esri.com/create-an-api-key.
  // Copy the API Key access token.

  const QString accessToken = QString("");

  if (accessToken.isEmpty())
  {
      qWarning() << "Use of ArcGIS location services, such as the basemap styles service, requires" <<
                    "you to authenticate with an ArcGIS account or set the API Key property.";
  }
  else
  {
      Esri::ArcGISRuntime::ArcGISRuntimeEnvironment::setApiKey(accessToken);
  }

  // Initialize the sample.
  ListRelatedFeatures::init();

  // Initialize application view
  QQuickView view;
  view.setResizeMode(QQuickView::SizeRootObjectToView);

  QString arcGISRuntimeImportPath = QUOTE(ARCGIS_RUNTIME_IMPORT_PATH);

#if defined(LINUX_PLATFORM_REPLACEMENT)
  // on some linux platforms the string 'linux' is replaced with 1
  // fix the replacement paths which were created
  QString replaceString = QUOTE(LINUX_PLATFORM_REPLACEMENT);
  arcGISRuntimeImportPath = arcGISRuntimeImportPath.replace(replaceString, "linux", Qt::CaseSensitive);
#endif

  // Add the import Path
  view.engine()->addImportPath(QDir(QCoreApplication::applicationDirPath()).filePath("qml"));
  // Add the Runtime and Extras path
  view.engine()->addImportPath(arcGISRuntimeImportPath);

  // Set the source
  view.setSource(QUrl("qrc:/Samples/Features/ListRelatedFeatures/ListRelatedFeatures.qml"));

  view.show();

  return app.exec();
}

Use case

How to use the sample

How it works

Relevant API

Tags

Sample Code