Building Cross-Platform Apps using Qt and Qyoto

1. Development of Cross
Platform Apps using
Qyoto and Qt
Jeff Alstadt

2. ABOUT CENTARE
fast. forward. thinking.
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3. OF NOTE
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iOS, Java, C#, Silverlight/XAML
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Certified Professional Scrum Trainers

4. Good Morning

5. Why Qt and why Qyoto
AGENDA
GETTING STARTED WITH Qt
and Qyoto

6. BUT ISNT QT DEAD?
Quite the opposite, it is living strong.
Qt is being used by 450,000 developers in 70
industries
Qt increases productivity by 70% with reduced
development costs of 75%
These guys are using Qt:

7. WHAT IS QT
What is Qt?
How is Qt Cross-Platform?
How do Qyoto and Qt work
together?
How can I use Qyoto in my apps?

8. WHAT IS QT?
Qt is a cross-platform UI framework that was
developed by Trolltech, later acquired by Nokia
for creating UIs that can run on the Mac, Linux
and Windows platform
Qt utilizes a moc compiler known as the Meta
Object Compiler with several macros to provide
the Qt specifics of the Qt language

9. THE FOUNDERS OF QT
Haavard Nord and Eirik Chambe-Eng founded
Qt with its initial development in 1991.
The toolkit was called Qt becuase the letter Q
looked appealing in Haavard‘s Emacs font and
“t“ was inspired by Xt, the X toolkit

10. GETTING STARTED WITH QT CREATOR
Qt Creator is the cross-platform developer IDE
It has a C++ compiler support built in, Qt centric UI designer
tools, and solid debugger. Works on all three platforms including
Mac, Linux and Windows

11. WHAT IS QYOTO?
Qyoto is a C# language binding for Qt.
It is not officially supported by Nokia or Digia
It is an open source community driven project
with a lot of the work coming from KDE
contributors
The top contributors of Kyoto are Arno Rehn, Ian
Moore, and Dimitri Dobrev

12. CONCEPTS OF QT DESIGN
Signals and Slots
Qt Property System
Qt Event System
Using Model View in Qt

13. SIGNALS AND SLOTS
A MEANS TO COMMUNICATE DATA
Signal Specific concept in Qt
Creates the construct to every Qt developer needs
to know
Type safe
Decoupled
Objects inherited from
QObject will only receive
the signal notifcations
connect connects the
object signal to the
respective slot

14. SHOW ME THE CODE:

15. SHOW ME THE C# CODE
[Q_OBJECT]
public class Counter
{
public Counter()
{}
private int m_value;
[Q_SLOT]
public void setValue(int value)
{
if ( m_value != value)
{
m_value = value;
emit valueChanged(value);
}
}
}

16. QT PROPERTY SYSTEM
The Qt system provides a
means to set any property in
the Qt Meta-Object System
The Qt solution works with
any standard C++ compiler
Qt supports
Q_PROPERTY is a macro that
is used to declare property
This declaration must be
done inside a QObject

17. QT EVENT SYSTEM
An event is an object or a set of objects
derived from the abstract class QEvent
Events represent things that have happened
either within an application or as a result of
outside activity that the application needs to
know about
Events are recieved and handled by instance
of a derived QObject class

18. LIST OF COMMON EVENT TYPES
QResizeEvent (Window Resizing)
QPaintEvent (Window Repainting)
QMouseEvent (Mouse Input)
QKeyEvent (Keyboard Input)
QCloseEvent (Window close)

19. SENDING EVENTS
In Qt, we can utilize the QCoreApplication to create and send our
own custom events.
To do this, we utilize sendEvent() and postEvent().
sendEvent() processes the event immediatly.
postEvent() posts the event on queue for later dispatch When Qt‘s
main event loop runs, it will then dispatch all posted events.
To create a custom Qt Event type, simpily subclass your event from
QEvent and ensure it has an event number that is greater than
QEvent::User (1000 presently in 4.8)
For all events, check here

20. USING MODEL VIEW IN QT
Qt has an advanced Model View archictecture concept
that was inspired from the MVC approach
Instead Qt utilizes a delegate instead of a controller
The delegate is used to provide a fine control over how
items are rendered and edited
For Qt specific views, Qt provides the appropriate
delegate for that view

21. COMMON PREDEFINED QT MODELS
QStringListModel
QStandardItemModel
QDirModel
QSqlQueryModel
QSqlTableModel
QSqlRelationalTableModel
QSortFilterProxyModel

22. GREAT HOW DO I GET A ROCKIN‘ WITH
QYOTO
To set up Qyoto you will need a fresh Linux install
of your favorite Linux distro (I chose Ubuntu)
Next you will need to download and install the Qt
SDK, Mono, MonoDevelop, Gtk2.0, QScintella 2.0,
Phonon lib, smoke gen
My blog has more details how to set up your box.

23. QYOTO DEMO
Overview of using mono develop with qyoto
Will be shown on Linux

24. QT IN MOBILE
Qt on Android
Qt on iOS

25. QT ON ANDROID
The Necessitas project is a community driven
lighthouse based port of Qt to Android
It has a plugin for Qt Creator to do Android
development
An installer application for Android called
Ministro exists
Ministro is responsible for downloading the Qt
libraries specific to that Android device

26. QT ON IOS
The Qt Lighthouse project was an initiative to
get Qt running on the iOS platforms.
It has had success, and is being integrated
with Qt 5.0

27. ONWARD TO QT 5
Qt 5 brings on a lot of new changes.
QML plays a bigger role in UI design
JavaScript will be heavily used over C++
Its objectives are
Make better use of the GPU, allowing you to create smooth (and
accelerated) graphics performance even with limited resources
Making your creation of advanced applications and UIs easier
and faster (with QML and Javascript)
Make apps connected to the web be as powerful as possible, i.e.
to embed and power up web content and services into any Qt
app
Reduce the complexity and amount of code required to
maintain and implement a port

28. VISION FOR QT 5
“Qt 5 should be the foundation for a new way
of developing applications. While offering all
of the power of native Qt using C++, the focus
should shift to a model, where C++ is mainly
used to implement modular backend
functionality for Qt Quick” – Lars Knoll, Qt
Project

29. QT 5 ARCHITECTURE CHANGES
Rearchitecture of the graphics stack
QtQuick and QML Scenegraph will be the center of the new graphics
architecture
QPainter will still be available
Qt 5 will require OpenGL 2.0
Qwidgets will be layered on top of the scene graph
Qt ports will be based on Lighthouse
Lighthouse provides a better windows abstract system
Modular repository structure
Speeds up the integration process of contributions to the Qt
framework
Seperation of all QWidget related functionality into its own library
QML will be the UI defacto, where QWidget will be there to support
older Qt apps

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