Writing the UI code

Once the .ui file has been created with Qt Designer, we can now write the code that will manage the functionality behind the UI. This will be in a Python file of the same name as the .ui file in the unitconverter.gui package.

As always, we will start the Python file with the imports for the modules and functions used within the file:

import os.path
from PyQt4 import uic
from PyQt4.QtGui import QApplication, QMainWindow
from PyQt4.QtCore import SIGNAL
from ..Converter import get_table

Next, we will load the .ui file in order to create an instance of the user interface it defines. This is done by replacing the extension of the full file path of the Python source file with .ui.

ui_filename = os.path.splitext(__file__)[0] + '.ui'
ui_UnitConverter = uic.loadUiType(ui_filename)[0]

We will now define a class named UnitConverter, which provides the functionality for the user interface. This class will inherit from both QMainWindow and the user interface class created when the .ui...