Lucas Danzinger & Koushik Hajra

ArcGIS Runtime SDK for Qt:Building Apps

• What is Qt• ArcGIS Runtime SDK for Qt capabilities• Getting started• Fundamental development patterns• How Esri uses Qt• Where to go from here

Agenda

What is Qt?

What is the Qt Framework?

• Write once, run anywhere• Builds as native C++Portable

• Cross-platform libraries• High-level abstractions

Approach-able

• Pre-built some platforms• Source code availableOpen

- Cross platform libraries for native app development- Business logic in C++. - UI in QML (JavaScript-based)- Write once, deploy everywhere

- Linux, Windows, Mac, iOS, Android

- Platform nuances are abstracted- Abstraction APIs for common native workflows

- HTTP, local data storage, sensors, Bluetooth, etc

Qt Framework

How does it work?

Android (via JNI & NDK)

iOS(via cocoa)

macOS(via cocoa) Linux Windows

Native platformAPIs (http, file i/o,

sensors etc)

Java Objective C Objective C C++ C++

Qt Abstracted APIQNetworkManager,

QFile, etc

Qt GUI (and other) LibrariesComboBox, Button,Charts, QImage

Your App

Language

C++ Compiler clang/gcc clang clang gcc MSVC

Platform

• Windows – x86, x64• Linux – x64, arm 64 (beta)• macOS – x64• Android – armv7, armv8, x86• iOS – arm64, sim

Which platforms can I build for?

ArcGIS Runtime SDK for Qt capabilities

Offline Maps/Scenes

ArcGIS Runtime SDK for Qt

Offline Routing Offline GeocodingOffline Geometry

Symbols & Renderers(with customizations)

Geoprocessing

Search/Identify/Query/Popups

ArcGIS Platform& IdentityUtility Network

Navigation

Augmented Reality

Data Collectionand editing

Koushik Hajra

ArcGIS Runtime SDK for Qt Capabilities

Getting started

• Setup Qt: - Create account- Commercial license / open-source?- Install kits for target platforms

• Setup ArcGIS Runtime SDK for Qt- Create developer account- https://developers.arcgis.com/qt/latest/

• Install compiler / SDK dependencies- macOS/iOS: Xcode compiler- Windows: Visual Studio compiler, debugging tools- Linux: GCC compiler- Android: Android NDK and SDK

• IDE- Qt Creator

Setup

App development patterns

App Pattern API to useIdeal place to

start for

Runs on Linux, macOS & Windows

Runs on iOS & Android

QML with Qt Quick QML Web Developer Yes Yes

C++ with Qt Quick C++ C++ Developer Yes Yes

C++ with Qt Widgets C++ C++ Developer Yes No

Commonly-used pattern

https://developers.arcgis.com/qt/latest/qml/guide/qt-sdk-best-practices.htm

The QML API

• QML is a declarative language from The Qt Company- Declare components similarly to writing JSON or CSS

• Write procedural code as JavaScript functions • Create UI rapidly with Qt Quick, with animation and prebuilt controls• The QML API extends QML with new types that expose ArcGIS Runtime functionality• Used by AppStudio

The C++ API

• Flexible: Create your UI with Qt Quick (targets any platforms) or Qt Widgets (targets desktop platforms)

- Most common design pattern: QML UI, C++ business logic

• Works with Local Server (QML API doesn’t)

Need help choosing between C++ and QML APIs? See https://developers.arcgis.com/qt/latest/qml/guide/qt-sdk-best-practices.htm

Koushik Hajra

Building your first ArcGIS Runtime Qt app

Runtime fundamental patterns + Qt

Asynchronous API

• The Runtime API is a modern, asynchronous API• Tasks

- RouteTask, LocatorTask, OfflineMapTask, GeoprocessingTask, Map.save …- All follow the same pattern- All are Loadable - All have async functions to execute their tasks- TaskWatchers are returned for keep track of concurrent tasks

• Signals & Slots- Signal == “event”- Slot == “event handler”

- *Slots can be defined as standalone methods or inline lambda functions

Asynchronous API – example LocatorTask

Asynchronous API – example LocatorTask

Asynchronous API – example LocatorTask (QML)

Koushik Hajra

Asynchronous coding with Qt

Memory management

• C++ is not a managed language• Memory is not automatically handled for you

- Pros- Close to the metal- Fine tuned performance

- Fast

- Can run on memory constrained devices

- Cons- A little extra work for you

Memory management – Qt Parent/Child

• When you create a new object, you pass in a parent object. • When the parent object is deleted, so are the children• Can be any QObject – often you will see “this”• Any object you create on the heap, it is up to you to manage• Any object we return always has a parent (but you can re-set)

Memory management – Clean up when you are done

• Apps with lots of temporary graphics added and removed- You don’t want memory allocated for the lifetime of the app

• Signals passing through pointers- The parent object is set by our API- No leaks, but memory will grow each time it emits

• Use RAII – Resource Acquisition is Initialization- e.g. C++11 “smart pointers” – std::shared_ptr, std::unique_ptr- Other methods…

Memory management – QML

Koushik Hajra

C++ memory management

ListModels

• Qt’s way of doing MVC/MVVM• Mutable lists exposed as list models in Runtime API

- LayerListModel, GraphicListModel, etc

• List Models can be displayed with- ListViews- TableViews- GridViews

• Model – the data• View – what is displayed• Delegate – access the model’s “roles”

ListModels – Map Layer Documentation

ListModels – Map Layer List Example

Koushik HajraList Models

Wrap up

How is Esri using Qt?

Runtime Core (for testing)

How to get started using the SDK• Create a developer account

- https://developers.arcgis.com/sign-up

• Download Qt Framework and ArcGIS Runtime SDK for Qt- https://developers.arcgis.com/qt/latest/cpp/guide/install-and-set-up-on-windows.htm et al

• Read the guide’s fundamental topics- https://developers.arcgis.com/qt/latest/qml/guide/arcgis-runtime-sdk-for-qt.htm

• Study and modify the samples- https://github.com/Esri/arcgis-runtime-samples-qt

• Use the Forum and join the community discussion- https://geonet.esri.com/community/developers/native-app-developers/arcgis-runtime-sdk-for-qt/