View source for PySideSimplicissimus Module 4 ShowLicence

[[Category:LanguageBindings]]
[[Category:PySide]]

* '''Note:''' this article is a member of the multipart [[PySide-Newbie-Tutorials]]

'''English''' [[http://qt-devnet.developpez.com/tutoriels/pyside/simplissimus/3-licence/ French]] [[PySideSimplicissimus_Module_4_ShowLicence_Japanese|日本語]]

= Show Licence =

Please note that this example shows the '''CCPL''' license, whereas [[PySide]] is released under '''LGPL'''. So make sure that you are displaying the right license.

All current source code for "Close", "About", "Show Licence", all versions of "Combined", "Engineering Application" aka "truss" are stored in one repository '''tuts4pyside'''. For your convenience, please install a copy of the repository with the following command:

<code> git clone https://github.com/OldAl/tuts4pyside</code>

If you do not have git, pllease install it first.
After downloading, place the '''CCPL.txt''' in the same directory as the program. The file has the '''Creative Commons Attribution-Share alike Licence''' text. '''licence.ui''' needs to be converted to Python file as follows:

<code> pyside-uic licence.ui > ui_licence.py</code>

'''Program Listing:''' follows:
<code>
#!/usr/bin/env python
# licence.py - display GPL licence

import sys

from PySide.QtGui import QApplication, QMainWindow, QTextEdit, QPushButton

from ui_licence import Ui_MainWindow

class MainWindow(QMainWindow, Ui_MainWindow):
 def __init__(self, parent=None):
 '''Mandatory initialisation of a class.'''
 super(MainWindow, self).__init__(parent)
 self.setupUi(self)
 self.showButton.clicked.connect(self.fileRead)

def fileRead(self):
 '''Read and display GPL licence.'''
 self.textEdit.setText(open('COPYING.txt').read())

if __name__ == '__main__':
 app = QApplication(sys.argv)
 frame = MainWindow()
 frame.show()
 app.exec_()
</code>

If you run the program and click the button, it will show in the TextEdit window the listing of the licence. All of the code mimics closely that of '''About''' and '''Close''' scripts. Two statements are of some interest:
<code>
self.showButton.clicked.connect(self.fileRead)
</code>
The purpose of the pushButton is to show the licence, so it has been named '''showButton'''. The above statement connects the showButton.clicked event with a class method '''fileRead'''. Thus when showButton is clicked, the Python class method '''fileRead''' is executed. That method has a single "Pythonised" statement:
<code>
self.textEdit.setText(open('COPYING.txt').read())
</code>
Not the simplest way to show what happens, but Python programmers like to do such things to us, readers. The code is equivalent to a series of statements as follows:
<code>
#open file
fl = open('COPYING.txt')
tmp = fl.read()
self.textEdit.setText(tmp)
</code>
It may be clearer, but a lot more typing and somewhat slower as Python is an interpreter. It is a subjective judgement which of the two styles is better.