PySide Beginner Examples

The purpose of this page is to cover beginner level examples of the PySide GUI manager (accompanying pages cover aspects that are more advanced).

Newcomers to GUI programming may stumble over the word "widget". It's meaning outside of computing is usually given as

"'a small gadget or mechanical device, especially one whose name is unknown or unspecified'"

For GUI work such as PySide the term "widget" is most often used to refer to the visible elements of the GUI - windows, dialogs, and input/output features. All visible elements of PySide are called widgets, and, for those who are interested, they all descend from a common parent class, QWidget. In addition to the visible elements PySide also offers widgets for networking, XML, multimedia, and database integration.

A widget that is not embedded in a parent widget is called a window and usually windows have a frame and a title bar. The most common types of windows are the "main window" (from the Class QMainWindow) and the various subclasses of the dialog (from the Class QDialog). One big difference is that QDialog is modal (i.e. the user can not do anything outside of the Dialog window while it is open) and the QMainWindow is non-modal which allows the user to interact with other windows in parallel.

This guide is a shortcut list for getting a PySide program working quickly under FreeCAD, it isn't intended to teach Python or PySide. Some sites that do that are:
 * PySide tutorial at zetcode.com
 * PySide/PyQt Tutorial at PythonCentral.io
 * PySide 1.0.7 Reference at Srinikom.github.io (note this is a reference, not a tutorial)

Import Statement
PySide is not loaded with Python by default, it must be requested prior to using it. The following command:

causes the 2 parts of PySide to be loaded - QtGui holds classes for managing the Graphic User Interface while QtCore contains classes that do not directly relate to management of the GUI (e.g. timers and geometry). Although it is possible to only import the one that is needed, generally they are both needed and both imported.

Note : the 'import' statement is not repeated in each code snippet below, it is assumed that it is already in the Python file.

The simplest interaction with PySide is to present a message to the user which they can only accept:



The next most simple interaction is to ask for a yes/no answer:

QtGui.QMessageBox.No, QtGui.QMessageBox.No) if reply == QtGui.QMessageBox.Yes:       # this is where the code relevant to a 'Yes' answer goes         pass if reply == QtGui.QMessageBox.No:         # this is where the code relevant to a 'No' answer goes         pass



The next code snippet asks the user for a piece of text - note this can be any key on the keyboard really:



Remember that even if the user enters only digits, "1234" for example, they are strings and must be converted to number representation with either of the following: