Qt is a cross-platform application and UI framework for developers using C++ or QML, a CSS & JavaScript like language. Cascades leverages the Qt object model, event model, and threading model, using QtCore, QtXML, QtSql, QtNetwork and QtSensors. The Cascades UI elements are available through C/C++ bindings and using QML.

Qt 4.8 is included in the BlackBerry 10 Devices and is also available in the Native SDK. A release includes matched builds for win32, linux32, win64, linux64, macosx on the Native SDK and for armle-v7 and x86 on the devices.

Getting started

The Qt Api Documentation provides some good examples on how to get started with Qt.

UI Creation

UIs in Qt can be either written using Widgets or Qt Quick. Because Widgets have its origin in the desktop world and are more or less static, it is recommended to use Qt Quick and QML for UIs on mobile platforms.

Qt Quick

Qt Quick is a set of technologies built on top of Qt providing the developers with the means to write fluid application UIs especially for mobile and embedded platforms.

The core of Qt Quick is the Java Script like QML language that allows the declaration of a user interface. QML code is executed at runtime by the Qt Declarative UI Runtime. Because Qt Quick runs on top of Qt, custom elements can be defined on the C++ side and exposed to QML (extending QML). Furthermore data can be exchanged between C++ and QML which makes it possible to seperate UI and logic from each other. In general it is recommened to have the business logic in C++ and the UI in Java Script.


BlackBerry 10 developers interact through two forums:

  • Developers using Qt as part of Cascades-centric applications use the Cascades Forum
  • Developers using Qt without Cascades-layer use the Native Forum

IRC: #qt-qnx on freenode

Filing Bugs

Defects or requests for enhancement can be submitted through the DevZone JIRA, which is monitored by members of the BlackBerry DevRel team.

BlackBerry 10 uses Qt from the upstream community at Gitorious/qt; issues that come from there can also in the corresponding BugReports.

Qt Samples


Also See

QNX on Qt-Project