2. 4
Design a GUI using QT Designer of PyQT4
 QT Designer
 Create widget
 Using Filter: Label
 Drag and drop to the new widget
 Adjust size
 Press Ctrl+R to view what you created
 Filter: Line Edit
 Drag and drop to widget
 Filter: Button
 Drag and drop a push button

3. 5
Signals and slots: Components communication
 Move from Edit Widget mode to Edit Signal/Slots
mode
 Or press F4
 Use F3 to go back to Edit Widget mode
 Next, we want the Push button to affect the Hello
world label
 Click and drug a line from the
button to the label

4. 6
Signals and slots: Components communication
 Select the result of the “IF-THEN” statement
 Select clicked() and Next clear()
 F3 to go back to Edit Widget mode
 Change the name
of the button to show Clear
 Ctrl+R
 Try it!

5. 7
Properties of the widget

6. 8
Signals and slots: Components communication
 We want the textbox to edit the label
 F4 to go to Edit Signal/Slots mode
 IF textChanged(QString) THEN setText (QString)

7. 9
Signals and slots: Components communication
 Ctrl+R
 Type to the text box
 IF push button THEN clicked()->clear()

8. 10
Edit widget
 F3
 Select Push button and Text box
 Lay out Horizontally
 Select 3 items
 Lay Out Vertically

9. 11
Edit widget
 Make the widget responsive
 Select Form: QWidget from Object Inspector
 Lay Out in a Grid
 Ctrl+R
 Resize widget size

10. 12
Save project and convert it to python script
 Save it as a ui file
 qt_hello.ui (like XML schema)
 Convert ui file to python code
 Open a command line
 C:Python27Libsite-packagesPyQt4
 pyuic4 -o OutFile_ui.py InFile.ui
 Pyuic4.bat file is in
 C:Python27Libsite-packagesPyQt4

11. 13
Execute your script using python
 Open qt_hello.py using an editor
 Add import sys after from PyQt4 import QtCore, QtGui
 At the end of your code add:
def main():
app = QtGui.QApplication(sys.argv)
window = QtGui.QDialog()
ui = Ui_Form()
ui.setupUi(window)
window.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()
System-specific parameters
and functions
Define a new function called main()
without any parameters
The QDialog class is the base class of
dialog windows.
A dialog window is a top-level window
mostly used for short-term tasks and
brief communications with the user.
Initializes the window system and
constructs an application object
with argc command line arguments
in argv. sys. argv is a list in Python,
which contains the command-line
arguments passed to the script.Form created
from QT Designer
When the Python interpreter reads a source
file, it executes all of the code found in it.

12. 14
Execute your script using python
 Open cmd (command shell)
 python py_hello.py
 In a lab pc you have to write the full path of python from
the folder that you save the py_hello.py file, e.g.
 C:Python27python py_hello.py