Many developers favor the creation of graphical user interfaces by hand-coding the layout of the interface elements. Most often than not, the resulting code is a highly cohesive mix of user interface and business logic that is not easy to maintain. Likewise, the development of custom widgets is often approached by subclassing top-level classes and overriding paint and event-handling methods. While this is the only alterantive for certain types of custom widgets, there is a big percentage that could be more easily created by composition of smaller widgets assembled together to work in as a unit.

This tutorial aims to share the following with the audience:

• Make a case for the benefits of using supporting tools for designing the layout portion of graphical user interfaces. In particular, the use of QtDesigner and code generators.
• Present a pattern and project structure for creating PyQt widgets that can also be used inside QtDesigner.
• Efficient use of composition over inheritance for assembling elaborate custom widgets more easily.

All material is based on Python and PyQt4. Audience is expected to have working knowledge of PyQt. Or, at least proficiency developing application in Qt and C++.

This tutorial is based on PyQt4 but concepts and techniques can be easily transferrable to PySide. Attendees require access to a computer with the following:

• Qt 4.5.2 or later.
• PyQt 4.5.4 or later.
• sip 4.8.2 or later.
• QtDesigner.
• Python plugin for QtDesigner.
• Python 2.5.x, 2.6.x or 2.7.x.

An easy way to check whether the Python plugin is available or not is to select from QtDesigner's main menu: Help > About Plugins > Loaded Plugins, should show libpythonplugin.so. This is normally installed automatically by the Qt installer.