Identify graphics

View inC++QMLView on GitHubSample viewer app

Display an alert message when a graphic is clicked.

screenshot

Use case

A user may wish to select a graphic on a map to view relevant information about it.

How to use the sample

Select a graphic to identify it. You will see an alert message displayed.

How it works

  1. Create a GraphicsOverlay and add it to the MapView.
  2. Add a Graphic along with a SimpleFillSymbol to the graphics overlay.
  3. Create a Point from the location clicked on the map view by the user from the MapQuickView::mouseClicked signal.
  4. Identify the graphic on the map view with identifyGraphicsOverlayAsync(GraphicsOverlay*, QPointF, double, bool, int).

Relevant API

  • Graphic
  • GraphicsOverlay
  • MapView

Tags

graphics, identify

Sample Code

IdentifyGraphics.cppIdentifyGraphics.cppIdentifyGraphics.hIdentifyGraphics.qml
Use dark colors for code blocksCopy
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
// [WriteFile Name=IdentifyGraphics, Category=DisplayInformation]
// [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 "IdentifyGraphics.h"

#include "Map.h"
#include "MapQuickView.h"
#include "SpatialReference.h"
#include "GraphicsOverlay.h"
#include "SimpleFillSymbol.h"
#include "SimpleRenderer.h"
#include "PolygonBuilder.h"
#include "Graphic.h"
#include "MapTypes.h"
#include "SymbolTypes.h"
#include "GraphicsOverlayListModel.h"
#include "GraphicListModel.h"
#include "IdentifyGraphicsOverlayResult.h"
#include "Geometry.h"

#include <QFuture>
#include <QMouseEvent>
#include <QList>
#include <QUuid>
#include <memory>

using namespace Esri::ArcGISRuntime;

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

IdentifyGraphics::~IdentifyGraphics() = default;

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

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

  // find QML MapView component
  m_mapView = findChild<MapQuickView*>("mapView");

  // Create a map using the topographic basemap
  m_map = new Map(BasemapStyle::ArcGISTopographic, this);
  // set map on the map view
  m_mapView->setMap(m_map);

  // create a new graphics overlay
  m_graphicsOverlay = new GraphicsOverlay(this);

  // assign a renderer to the graphics overlay
  SimpleFillSymbol* simpleFillSymbol = new SimpleFillSymbol(SimpleFillSymbolStyle::Solid, QColor(255, 255, 0, 180), this);
  SimpleRenderer* simpleRenderer = new SimpleRenderer(simpleFillSymbol, this);
  m_graphicsOverlay->setRenderer(simpleRenderer);

  // add the overlay to the mapview
  m_mapView->graphicsOverlays()->append(m_graphicsOverlay);

  // add polygon graphics
  addPolygonGraphic();

  // connect signals
  connectSignals();
}

// create the polygon geometry and graphic
void IdentifyGraphics::addPolygonGraphic()
{
  // create the polygon using the builder class
  PolygonBuilder polygonBuilder(SpatialReference::webMercator());
  polygonBuilder.addPoint(-20e5, 20e5);
  polygonBuilder.addPoint(20e5, 20e5);
  polygonBuilder.addPoint(20e5, -20e5);
  polygonBuilder.addPoint(-20e5, -20e5);

  // create the graphic and add to the graphics overlay
  Graphic* graphic = new Graphic(polygonBuilder.toGeometry(), this);
  m_graphicsOverlay->graphics()->append(graphic);
}

void IdentifyGraphics::connectSignals()
{
  //! [identify graphics api snippet]
  // connect to the mouse clicked signal on the MapQuickView
  connect(m_mapView, &MapQuickView::mouseClicked, this, [this](QMouseEvent& mouseEvent)
  {
    // call identify on the map view
    constexpr double tolerance = 5.0;
    constexpr bool returnPopupsOnly = false;
    constexpr int maximumResults = 1;

    m_mapView->identifyGraphicsOverlayAsync(m_graphicsOverlay, mouseEvent.position(), tolerance, returnPopupsOnly, maximumResults).then(this,
    [this](IdentifyGraphicsOverlayResult* rawIdentifyResult)
    {
      // Delete rawIdentifyResult on leaving scope.
      auto identifyResult = std::unique_ptr<IdentifyGraphicsOverlayResult>(rawIdentifyResult);

      if (identifyResult)
      {
        m_identifiedGraphicsCount = identifyResult->graphics().size();
        emit identifiedGraphicsCountChanged();
      }
    });

  });
  //! [identify graphics api snippet]
}

int IdentifyGraphics::identifiedGraphicsCount()
{
  return m_identifiedGraphicsCount;
}

Your browser is no longer supported. Please upgrade your browser for the best experience. See our browser deprecation post for more details.