Software development with qt

Software Development with Qt Andreas Jakl Senior Technical Consultant Forum Nokia 13 April, 2010

13.04.2010 © 2010 Nokia 2 Qt in a Nutshell Qt is a class library for platform independent development of graphical user interfaces based on C++. The framework also includes XML, databases, multithreading, network, internationalization, 3D, WebKit, multimedia, etc.

13.04.2010 © 2010 Nokia 3 Short History of Qt Focus on mobile platforms (Symbian, Maemo, MeeGo), dedicated mobility APIs Nokia purchases Trolltech, name changes to Qt Development Frameworks APIs Qt 4.0 – compatibility break, leads to new KDE 4 desktop Qtopia – platform for mobile phones & PDAs First public release through newsgroups (Qt 0.90) • Dual licensing: commercial & free for open source Decided to go into business • “Q” looked beautiful in Emacs font. “t” for toolkit • Company : Quasar Technologies (later: Trolltech) Development started • Cross platform GUI toolkit was needed Eirik Chambe-Eng Haavard Nord

13.04.2010 © 2010 Nokia 5 Qt Licensing • LGPL license • Qt is completely free! – Unlike GPL, the LGPL: • Allows using Qt for free in commercial, closed source apps – Complete development source code of Qt available • Commercial version – Code changes to Qt source code don’t have to be shared – Included support options

13.04.2010 © 2010 Nokia 6 Platforms Windows Mac OS Linux / X11 C++ Embedded Linux Windows CE Maemo / MeeGo Java Symbian (S60) Python Ada Pascal Maintained by Perl Qt open source community. PHP Not officially supported by Qt Development Frameworks.

13.04.2010 © 2010 Nokia 10 Symbian and Qt • Qt for Symbian: – Compatible to S60 3rd. Edition, FP1+ (Nokia N95, E71) – Install SDK for your device, or lowest denominator for devices you want to support with your product • Info about system version of Nokia S60 devices: http://www.forum.nokia.com/devices/ Qt Compatibility Series 60 Series 60 S60 S60 S60 S60 Symbian^2 Symbian^3 Symbian^4 1st Ed. 2nd Ed. 3rd Ed. 3rd Ed. 3rd Ed. 5th Ed. (+ 3 FPs) FP1 FP2 = Symbian^1

© 2010 Nokia 12 Symbian and Qt • Symbian^4: replaces S60 with Qt-based UI • Components: – Uiemo (UI Extensions for Mobile, Orbit): extension library for Qt, 50+ UI elements tailored for mobile – Direct UI: new app framework based on Uiemo • Availability: – End of 2010 Symbian^4 Concept Video

© 2010 Nokia 13 Maemo / MeeGo and Qt • Maemo 5 – GTK+ based UI – Qt pre-installed – Final Qt support: H1 2010 (4.6.2) • MeeGo 1.0 N (formerly: Maemo 6) – Qt replaces GTK+ – Multi-touch, gestures support – GTK and Clutter will stay in MeeGo

© 2010 Nokia 14 MeeGo and Qt • Moblin (Intel) and Maemo (Nokia) merge to – New Linux distribution (Linux Foundation) – MeeGo UI toolkit based on Qt – GTK and Clutter included for application compatibility

© 2010 Nokia 15 Qt Architecture • Qt uses native styles to draw UI – UI elements have original look & feel – Can be adapted by the developer • Built on low level APIs of platform – No runtime! • Cross-platform – Single source for multiple platforms – Only requires recompilation

13.04.2010 © 2010 Nokia 17 Hello World Project main.cpp #include <QApplication> #include <QPushButton> int main(int argc, char *argv[]) { QApplication app(argc, argv); QPushButton helloButton("Hello World"); helloButton.resize(150, 50); helloButton.show(); return app.exec(); }

13.04.2010 © 2010 Nokia 18 Qt and C++ • Qt goes beyond C++ – Seamless object communication (signals & slots) – Meta object system, featuring object properties and object trees – Contextual string translation for internationalization • … but still works with standard C++ compilers on all platforms!

13.04.2010 © 2010 Nokia 19 Interactivity: Quit Hello World • Add functionality to exit the Hello World example: QObject::connect(&helloButton, SIGNAL(clicked()), &app, SLOT(quit())); – Button emits clicked() signal – Connected to QApplication::quit()

13.04.2010 © 2010 Nokia 20 Signals & Slots • Signal – Emitted when a particular event occurs (e.g., clicked()) – Qt widgets: predefined signals – Also create your own signals • Slot – Function called in response to a signal – Qt widgets: predefined slots (e.g., quit()) – Also create your own slots • Connection signals  slots established by developer, handled by Qt framework

The Future of Qt

© 2010 Nokia 23 Qt Quick (Qt User Interface Creation Kit) • Create UIs as a designer – Without C++ knowledge – Using visual tools – Module: Declarative UI – Based on QML language (extension to JavaScript) – Supported in Qt 4.7 – http://blog.qt.nokia.com/2010/02/15/meet-qt-quick/

© 2010 Nokia 24 QML • Describe UI by tree structure of property bindings – Properties dynamically evaluated – Communication through Rectangle { signals & slots width: 200 – Bindings to C++ code possible height: 200 color: "white" – Animate properties using states Image { source: "pics/logo.png" and transitions anchors.centerIn: parent } }

© 2010 Nokia 25 UI Framework (Uiemo) • Scene graph approach to the UI • Optimized for – Graphics effects, 3D HW acceleration – Gestures, multi-touch, kinetics • Adventurous? – It’s open source! – Symbian: http://qt.gitorious.org/uiemo

13.04.2010 © 2010 Nokia 27 Advantages of Hybrid Applications Web Qt HTML, CSS, JavaScript C++ Rapid development Full device access Broad reach Powerful libraries Embed Qt UI elements into HTML page Access Qt objects from JavaScript Trigger JavaScript from Qt Shared storage http://qt.nokia.com/forms/whitepapers/reg-whitepaper-hybrid

13.04.2010 © 2010 Nokia 28 Qt Mobility • Qt: Desktop → Mobile • Requires new APIs for – Sensors – Location – Messaging – etc. • Qt Mobility: new cross-platform APIs for mobile use cases – Back-end implementation on all platforms where it makes sense

13.04.2010 © 2010 Nokia 29 Smart Installer • Distribute Qt apps on Symbian devices – Qt not pre-installed on current phones – Solution: installation / update on demand – Package Smart Installer with your app • Download – http://qt.nokia.com/developer/nokia-smart-installer-for-symbian – Final: H1 2010

13.04.2010 © 2010 Nokia 31 Qt Books C++ GUI Programming with Qt 4 (2nd edition) Jasmin Blanchette, Mark Summerfield. Prentice Hall. Official book for Qt development. Good for looking things up or for enhancing your knowledge, average for learning from scratch. Status: Qt 4.3, 2008 Foundations of Qt Development Johan Thelin. Apress. More in-depth and technically oriented explanation of Qt. Most other books are rather similar to the official documentation that you get for free with the SDK – this is different, and is therefore a good companion. Status: 2007

13.04.2010 © 2010 Nokia 32 Even More Information Qt for Symbian Editors: Frank H. P. Fitzek, Tommi Mikkonen, Tony Torp. Wiley. For Qt developers wanting to get started with development on the mobile Symbian platform, or the other way round. Status: Qt 4.6, April 2010 Online: qt.nokia.com, www.forum.nokia.com, www.qtcentre.org Lots of documentation and examples installed with SDK

Thank You.

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Software development with qt

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