Qt is a cross-platform application framework for building graphical user interfaces and Qt QML is a declarative language that allows building user interface elements. Qt Creator is an integrated development environment for developing Qt applications. Qt supports developing Android applications that have native look and feel and access device capabilities while being written once and deployed across platforms. Qt applications have large size but provide powerful and native UI libraries and cross-platform capabilities.

1. QtQml

2. Outline
• What is Qt ?
• What is Qml?
• Qml Elements
• Qt creator
• Qt on Android

3. What is Qt ?
• Cross-platform GUI application framework
• Written in C++
• Open Source
• Qt modules: Qt Core, Qt GUI, Qt QML, Qt Quick, Qt
Network, Qt Multimedia, Qt WebKit, Qt SQL …
• Software developed by Qt
– Perforce , tesla , VLC , google earth, Mathematica,
jewelrybox …

4. What is Qml ?
• Qt Meta Language
• JavaScript-based, declarative language for
designing user interface–centric app
• Support by QtQuick (the standard library for
writing QML applications)
• Mainly for mobile app
• Qml element easily to be extended by javascript
and C++ class
• Qml can use various qt modules

5. Qt Elements
• Item– basic element
• Rectangular – inherit from items
• Component --encapsulated QML types
• Animation
• Model --contains the data and its structure
• Delegate--dictates how the data should appear in the view
• View--a container that displays the data
– Pathview
– Grid view
– List view

6. Qt creator
• IDE
• Layout
• Example :
– calqlatr (java script)
– Calendar (c++)

7. QML on Android
• Support for native android style with Qt Quick Controls ,not
yet included material design
– http://doc.qt.io/qt-5/android-support.html
– http://doc.qt.io/qt-5/qtquickcontrols-
platformnotes.html#android-style
• Support most of Qt modules: multimedia , sensor reading,
GPS , bluetooth…
– http://doc.qt.io/qt-5/examples-android.html
• Develop on Qt creator

8. Qt Android Extras
• The way to call the android java api
• Example : qt notifier
http://doc.qt.io/qt-5/qtandroidextras-
notification-notificationclient-cpp.html
• Qt thread & Android thread
– http://www.kdab.com/qt-android-episode-7/

9. Pros
• Cross-platform
• powerful UI libraries
• IDE: Qt Creator
• Native-look
• Performance is the same with (maybe better than)
native app
– Qt Core is written in high performance C++
– Utilize hardware acceleration
– http://stackoverflow.com/questions/22460127/how-slow-or-fast-is-qt-
mobile-for-android
– http://www.developereconomics.com/cross-platform-apps-qt-vs-
html5/
– http://v-play.net/2014/10/qt-vs-html5-cross-platform-apps/

10. cons
• Size is large
– 35MB for hello world
– http://achipa.blogspot.tw/2014/11/native-ui-in-
qt-on-android-without.html
• Need to compile QMl
• Licensing is confusing
– https://blog.qt.io/blog/2009/11/30/qt-making-
the-right-licensing-decision/