Introduction to PyQt4

Info

Creating an application in PyQT4 may be done in a few ways. The most common one is to use QTDesigner, which we get with QT. QTDesigner let us draw the GUI which is very handy for complicated interfaces. We can place widgets on the window, add names etc. To create an application in PyQT4 you have to:

Create the GUI in QTDesigner
Set names in the Property Editor to ease coding of the application (QTDesigner)
Using pyuic4 create the python GUI class
Call the application using that GUI class
Extend it with our own slots
When you use a widget you go to PyQt's Classes and check methods of each used widgets. The method names as "setText" are very easy to understand.

Tutorials List

Simple text editor in PyQT4 - First application in PyQT4
Extending PyQT4 text editor - Adding more features using PyQT4 widgets
QYolk I - List widgets in PyQt4 - How to use list widgets in PyQt4
QYolk II - Containers - How to use a Tab Widget
PyQT4 Text editor - final changes - Some advanced PyQT4 features
QYolk III - List of updates - A new feature

WebKit in PyQt - rendering web pages - qt-webkit provides WebKit API in the Qt library and it can be use in PyQt to render web pages
PyQt events - A description of Qt events, and QListWidget example of handling mouse events.
QtSql in PyQt4 - handling databases - Overview of QtSql classes in PyQt that allow managing databases and grid integration
QGraphicsView and QGraphicsScene - Description of widgets for visualizing 2D data (images etc.)
QTimer - making timers in PyQt4 - Description of timers available in PyQt4

QScintilla2 and PyQT4 - Adding widgets for programmers to PyQt4.
Making PyQt4 widgets with SIP - Tutorial on making PyQt4 widgets from Qt4 widgets using SIP.
PictureFlow - listing images in PyQt4 - PictureFlow - extra PyQt4 widget
Rendering PDF files in PyQt4 with pypoppler-qt4 - Description of pypoppler-qt4 - bindings for Poppler library.

Introduction

We start with a "Hello... Close Button". When you launch the QTDesigner you will be able to chose base window type:

We choose simple Widget, which will give us a simple window. From the right menu we drag one Push Button on to the window:

Right-Click on the pushButton will allow us to change its caption (displayed text).

When the GUI is done we can use QTDesigner to connect widgets with "simple" predefined slots - in our case we want the "close()" slot which will close the application. To do that we have to switch to Signal Editing:

To connect a widget with a signal press the mouse button over the pushButton and move the mouse pointer over the wiget window and then drop:

A Signal-Slots window should appear:

The signal is clicked() and slot is close. Now we save the gui as for example test.ui. In the terminal go to the folder with saved GUI (ui file) and type:

pyuic4 test.ui > test_ui.py

Next create test.py file with the code:

import sys
from PyQt4 import QtCore, QtGui

from test_ui import Ui_Form


class MyForm(QtGui.QMainWindow):
    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)
        self.ui = Ui_Form()
        self.ui.setupUi(self)


if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    myapp = MyForm()
    myapp.show()
    sys.exit(app.exec_())

And run it:

python test.py

You will see our application, and when you click the button it will close.

Notes

Ui_Form is the class name generated by pyuic4 the "Form" part is the name of the main window. You can change it in QTDesigner (we will do this in next tutorial). You have to change the objectName:

The code from test.py is a general code for running and extending GUI classes generated by pyuic4.

Tutorials List

Introduction

Notes

Categories