Qt DevDays 2012@Berlin talk: "Effective QML - part1"

1. Effective QML
Best practices for developing with Qt Quick
Adenilson Cavalcanti
Bsc. Msc.
KDE developer
WebKit contributor

2. Presentation structure
The case for QML
How to train yourself or a team
Overview on QML
Good practices
Advanced techniques
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3. What is this Q-Whatchamacallit?
Qt Meta Language (QML)*
Declarative vs Imperative
* http://en.wikpedia.org/wiki/QML
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4. A case study: QML x QGV*
Requirements:
1 top bar
1 lower bar
scrolling kinetic list in the center
re-scalable
*QGV stands for QGraphicsView
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5. A case study: QML x QGV
QGV vs QML: are different, but can solve similar
problems.
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6. A case study: QML x QGV
Which one will be more verbose?
Which one will be faster to develop?
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7. A case study: QML x QGV
Results
1600
1400
1200
1000
Lines of code
800 LOC
600
400
200
0
QGV QML
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8. A case study: QML x QGV
A difference of almost 1000% in development time
QGV: 1 ½ day (8-10 hours)*
QML: 1 hour (+ 30 minutes for minor adjustments)
*Assuming a ready to use KineticScrolling list and a basic Button
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9. A case study: QML x QGV
Question: if you start a new project today, which
one will be done earlier?
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10. QML: what it means for...
Managers x designers x developers
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11. Should I put C++ out of the equation?
Porto de Galinhas (Pernambuco) - Brazil
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12. QML and C++
Relevant questions
Complexity
Functionality
Team
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13. What about QWidgets?
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14. How many QWidgets?
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15. 96 Widgets! Not counting all KDE widget or Qt add-ons...
Relevant questions
What your app need?
Desktop x Touchscreen
Animations?
Designer assets?
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16. Right tool to the right job
DevDays@California - 2008
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17. Trainment
How to become QML-proficient?
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18. Trainment
If you are a student
Yeah, Matrix.
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19. Trainment
Students: use the power of Opensource!
Great online documentation
Qt is opensource
KDE
gSoC
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20. Trainment
Lessons for students:
Making mistakes is part of learning process
The one who make more points is also the one
who makes more mistakes
While learning, look for the best!
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21. Relax time...
Ilha Bela (Sao Paulo) - Brazil
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22. Trainment
If you are a professional/manager
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23. Trainment
Qt has a real ecosystem
ICS (USA based)
KDAB (Europe)
Digia (owned Trolltech)
Collabora (ninja-ish guys)
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24. Services
If you need it today!!!11!
Must have Star Wars reference
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25. QML: 101
QML elements
Visual: Rectangle, Image, BorderImage, Text, TextEdit, TextInput,
AnimatedImage, Gradient
Positioner/Repeater: Column, Row, Grid, Flow, Repeater
Views: ListView, GridView, PathView
Utilities: Connection, Loader, Timer, WorkerScript,
Path(Line/Quad/Cubic/Attribute/etc)
Animations: Property, Number, Vector3d, Color, Rotation,
Parent, Anchor
Models: ListModel, ListElement, XmlListModel, etc
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26. QML: 101
We lack time to cover it all...
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27. The end?
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28. The end?
Not really...
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29. To be continued...
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