Display an alert message when a graphic is clicked.
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
- Create a
GraphicsOverlay
and add it to theMapView
. - Add a
Graphic
along with aSimpleFillSymbol
to the graphics overlay. - Create a
Point
from the location clicked on the map view by the user from theMapQuickView::mouseClicked
signal. - Identify the graphic on the map view with
identifyGraphicsOverlay(graphicsOverlay, mouseEvent.x(), mouseEvent.y(), tolerance, returnPopupsOnly, max results)
.
Relevant API
- Graphic
- GraphicsOverlay
- MapView
Tags
graphics, identify
Sample Code
// [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 "Basemap.h"
#include "GraphicsOverlay.h"
#include "SimpleFillSymbol.h"
#include "SimpleRenderer.h"
#include "PolygonBuilder.h"
#include "Graphic.h"
#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->identifyGraphicsOverlay(m_graphicsOverlay, mouseEvent.x(), mouseEvent.y(), tolerance, returnPopupsOnly, maximumResults);
});
// connect to the identifyLayerCompleted signal on the map view
connect(m_mapView, &MapQuickView::identifyGraphicsOverlayCompleted, this, [this](QUuid, 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;
}