Creating Main Window in Pyqt5

PyQt5 : Creating Main Window .

In this blog we will create our first window of PyQt5 and also try some basic methods for resize it or change it's title .

if you don't have any idea about PyQt5 then you can check introduction to PyQt5 .

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Creating Our first Window :

# PyQt5 : Dynamic Coding
# creating mainwindow .

from PyQt5.QtWidgets import QApplication,QWidget
import sys

class Example(QWidget):
    def __init__(self):
        super().__init__()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    ex = Example()
    ex.show()


    sys.exit(app.exec_())

Lets understand the code .

 at first we import the classes from pyqt5 and also import system module .

Note : PyQt5 is not built-in so please install it before use .

now we create a class of name Example and inherit Qwidget class into it now creating the constructor of Example and  also calling the constructor of Qwidget .

at last we used a if condition and if the condition is true then a object of QApplication and Example is created and we use ex.show( ) method to show our GUI on the screen .

What is QApplication( ) :

Every PyQt5 application must create an application object. The sys.argv parameter is a list of arguments from a command line. Python scripts can be run from the shell. It is a way how we can control the startup of our scripts. if you dont want to run the code from shell or cmd you can use  ' [ ] ' insted of sys.argv

What is QWidget ?

The QWidget widget is the base class of all user interface objects in PyQt5. We provide the default constructor for QWidget. The default constructor has no parent. A widget with no parent is called a window.

OUTPUT :

The output of above code will look like  .

Create window using QMainwindow 

Any Qwidget without a parent ( containing widget ) is its own window . This is a fine way to create windows however There is also a specific Qmainwindow  class. This class have few advantages over Qwidgets like it includes the use of toolbars , statusbar , Menu etc .

So lets code :

# PyQt5 : Dynamic Coding
# creating mainwindow .

from PyQt5.QtWidgets import QApplication,QMainWindow
import sys

class Example(QMainWindow):
    def __init__(self):
        super().__init__()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    ex = Example()
    ex.show()
    sys.exit(app.exec_())

The code gives us the output same as above window .

Changing title of window .

# PyQt5 : Dynamic Coding
# changing title .

from PyQt5.QtWidgets import QApplication,QMainWindow
import sys

class Example(QMainWindow):
    def __init__(self):
        super().__init__()

        self.setWindowTitle('Dynamic Coding')


if __name__ == "__main__":
    app = QApplication(sys.argv)
    ex = Example()
    ex.show()
    sys.exit(app.exec_())

For changing title i use a predefined method of PyQt5 =  setWindowTitle('string')

OUTPUT :

Set geometry and make it non resizable .

# PyQt5 : Dynamic Coding
# changing geometry .

from PyQt5.QtWidgets import QApplication,QMainWindow
import sys

class Example(QMainWindow):
    def __init__(self):
        super().__init__()

        self.setWindowTitle('Dynamic Coding')
        self.setGeometry(100,100,300,200) 
        self.setFixedSize(300,200)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    ex = Example()
    ex.show()
    sys.exit(app.exec_())

for setting the geometry we use setGeometry methods which takes four arguments and then are .

• position from X axis
• position from Y axis
• width of GUI
• height of GUI

and use setFixedSize method to seta fixed size of GUI to make it non resizable .

Adding Icon at mainwindow .

 

# PyQt5 : Dynamic Coding
# adding icon .

from PyQt5.QtWidgets import QApplication,QMainWindow
from PyQt5 import QtGui
import sys

class Example(QMainWindow):
    def __init__(self):
        super().__init__()

        self.setWindowTitle('Dynamic Coding')
        self.setGeometry(100,100,300,200)
        self.setFixedSize(300,200)
        self.setWindowIcon(QtGui.QIcon('icon.png'))


if __name__ == "__main__":
    app = QApplication(sys.argv)
    ex = Example()
    ex.show()
    sys.exit(app.exec_())

 

For adding icon we import another PyQt5 class QtGui and use it with a method named setWindowIcon and inside it call a QtGui method QIcon and pass the icon name .

Note : The icon size 12x12 is reccomended .

Check out our previous post on PyQt5 .

Introduction to PyQt5

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This blog is contributed by Yogesh singh .

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