Category: pyqt5

PyQt5 window

If you do not have PyQT5 installed, you should install it first.
In a terminal you can type:

sudo apt-get install python3-pyqt5

If you are on a Windows or Mac computer, you can download PyQT5 from: https://www.riverbankcomputing.com/software/pyqt/download5

Related courses:

Create GUI Apps with PyQt5

PyQt5 window

You can create a PyQT5 window using the code below:

import sys
from PyQt5.QtWidgets import QApplication, QWidget
from PyQt5.QtGui import QIcon
 
class App(QWidget):
 
def __init__(self):
super().__init__()
self.title = 'PyQt5 simple window - pythonspot.com'
self.left = 10
self.top = 10
self.width = 640
self.height = 480
self.initUI()
 
def initUI(self):
self.setWindowTitle(self.title)
self.setGeometry(self.left, self.top, self.width, self.height)
self.show()
 
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = App()
sys.exit(app.exec_())

We set the window size using the setGeometry(left,top,width,height) method. The window title is set using setWindowTitle(title). Finally show() is called to display the window.

Run with:

python3 window.py

Download PyQT5 Code

The output should look similar to the screenshot above (depending on your operating system).

PyQt5 statusbar

PyQt5 supports a window status bar. To add a status bar add the line:

self.statusBar().showMessage('Message in statusbar.')

A statusbar can be added to the main window (QMainWindow). It is one of the methods the class itself contains;

Related course:

Create GUI Apps with PyQt5

PyQt5 statusbar example:
The program below adds a statusbar to a PyQt5 window:

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QMainWindow
from PyQt5.QtGui import QIcon
 
class App(QMainWindow):
 
def __init__(self):
super().__init__()
self.title = 'PyQt5 status bar example - pythonspot.com'
self.left = 10
self.top = 10
self.width = 640
self.height = 480
self.initUI()
 
def initUI(self):
self.setWindowTitle(self.title)
self.setGeometry(self.left, self.top, self.width, self.height)
self.statusBar().showMessage('Message in statusbar.')
self.show()
 
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = App()
sys.exit(app.exec_())

The example creates a window (QMainWindow). We set the screen parameters using:

self.left = 10
self.top = 10
self.width = 640
self.height = 480

Window properties are set in the initUI() method which is called in the constructor. The method:

statusBar().showMessage()

sets the text on the statusbar.

Download PyQT5 Examples

PyQt5 supports buttons using the QPushButton class. This class is inside the PyQt5.QtWidgets group. The button can be created by calling the constructor QPushButton with the text to display as parameter.

Related course:

Create GUI Apps with PyQt5

Introduction
To use buttons with a PyQt5 application, we need to update our import line:

from PyQt5.QtWidgets import QApplication, QWidget, QPushButton
from PyQt5.QtCore import pyqtSlot

In the initUI() method, add these lines of code:

button = QPushButton('PyQt5 button', self)
button.setToolTip('This is an example button')
button.move(100,70)

QPushButton creates the widget, the first argument is text on the button.
The method setToolTip shows the message when the user points the mouse on the button.
Finally the button is moved to the coordinates x=100,y=70.
We need to create a method for a button click:

@pyqtSlot()
def on_click(self):
print('PyQt5 button click')

Add connect the method to the click with:

button.clicked.connect(self.on_click)

Final PyQt5 button code:

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton
from PyQt5.QtGui import QIcon
from PyQt5.QtCore import pyqtSlot
 
class App(QWidget):
 
def __init__(self):
super().__init__()
self.title = 'PyQt5 button - pythonspot.com'
self.left = 10
self.top = 10
self.width = 320
self.height = 200
self.initUI()
 
def initUI(self):
self.setWindowTitle(self.title)
self.setGeometry(self.left, self.top, self.width, self.height)
 
button = QPushButton('PyQt5 button', self)
button.setToolTip('This is an example button')
button.move(100,70)
button.clicked.connect(self.on_click)
 
self.show()
 
@pyqtSlot()
def on_click(self):
print('PyQt5 button click')
 
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = App()
sys.exit(app.exec_())

Screenshot of PyQt5 button example above.

Download PyQT5 Examples

PyQt5 signals and slots

Graphical applications (GUI) are event-driven, unlike console or terminal applications. A users action like clicks a button or selecting an item in a list is called an event.

If an event takes place, each PyQt5 widget can emit a signal. A signal does not execute any action, that is done by a slot.

Related course:

Create GUI Apps with PyQt5

Signals and slot introduction
Consider this example:

button.clicked.connect(self.slot_method)

The button click (signal) is connected to the action (slot). In this example, the method slot_method will be called if the signal emits.

This principle of connecting slots methods or function to a widget, applies to all widgets,

widget.signal.connect(slot_method)

or we can explicitly define the signal:

QtCore.QObject.connect(widget, QtCore.SIGNAL(‘signalname’), slot_function)

PyQt supports many type of signals, not just clicks.

Example
We can create a method (slot) that is connected to a widget. A slot is any callable function or method.

On running the application, we can click the button to execute the action (slot).

from PyQt5.QtWidgets import (QApplication, QComboBox, QDialog,
QDialogButtonBox, QFormLayout, QGridLayout, QGroupBox, QHBoxLayout,
QLabel, QLineEdit, QMenu, QMenuBar, QPushButton, QSpinBox, QTextEdit,
QVBoxLayout)
 
import sys
 
class Dialog(QDialog):
 
def slot_method(self):
print('slot method called.')
 
def __init__(self):
super(Dialog, self).__init__()
 
button=QPushButton("Click")
button.clicked.connect(self.slot_method)
 
mainLayout = QVBoxLayout()
mainLayout.addWidget(button)
 
self.setLayout(mainLayout)
self.setWindowTitle("Button Example - pythonspot.com")
 
if __name__ == '__main__':
app = QApplication(sys.argv)
dialog = Dialog()
sys.exit(dialog.exec_())

PyQt5 messagebox

In this article you will learn how to create a PyQt5 messagebox:

To show a messagebox we need to import QMessageBox.

from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QMessageBox

We use the method QMessageBox.question() to display the messagebox.

PyQt5 messagebox code

Copy the code below to display a messagebox.

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QMessageBox
from PyQt5.QtGui import QIcon
from PyQt5.QtCore import pyqtSlot
 
class App(QWidget):
 
    def __init__(self):
        super().__init__()
        self.title = 'PyQt5 messagebox - pythonspot.com'
        self.left = 10
        self.top = 10
        self.width = 320
        self.height = 200
        self.initUI()
 
    def initUI(self):
        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)
 
        buttonReply = QMessageBox.question(self, 'PyQt5 message', "Do you like PyQt5?", QMessageBox.Yes | QMessageBox.No, QMessageBox.No)
        if buttonReply == QMessageBox.Yes:
            print('Yes clicked.')
        else:
            print('No clicked.')
 
        self.show()
 
if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())

More buttons for a messagebox
Take into account we use QMessageBox.Yes and QMessageBox.No. We can easily add other options:

        buttonReply = QMessageBox.question(self, 'PyQt5 message', "Do you want to save?", QMessageBox.Yes | QMessageBox.No | QMessageBox.Cancel, QMessageBox.Cancel)
        print(int(buttonReply))
        if buttonReply == QMessageBox.Yes:
            print('Yes clicked.')
        if buttonReply == QMessageBox.No:
            print('No clicked.')
        if buttonReply == QMessageBox.Cancel:
            print('Cancel')

The available buttons are:

Overview
QMessageBox.Cancel	QMessageBox.Ok	QMessageBox.Help
QMessageBox.Open	QMessageBox.Save	QMessageBox.SaveAll
QMessageBox.Discard	QMessageBox.Close	QMessageBox.Apply
QMessageBox.Reset	QMessageBox.Yes	QMessageBox.YesToAll
QMessageBox.No	QMessageBox.NoToAll	QMessageBox.NoButton
QMessageBox.RestoreDefaults	QMessageBox.Abort	QMessageBox.Retry
QMessageBox.Ignore

Download PyQT5 Examples

PyQt5 textbox example

In this article you will learn how to use a textbox in PyQt5. The widget is called QLineEdit and has the methods setText() to set the textbox value and text() to get the value.

We can set the size of the textbox using the resize(width,height) method. The position can be set using the move(x,y) method or using a grid layout.

Related course:

Create GUI Apps with PyQt5

PyQt5 textbox
Creation of the textbox is fairly straightforward:

self.textbox = QLineEdit(self)
self.textbox.move(20, 20)
self.textbox.resize(280,40)

PyQt5 textbox example

The example below creates a window with a textbox.

import sys
from PyQt5.QtWidgets import QMainWindow, QApplication, QWidget, QPushButton, QAction, QLineEdit, QMessageBox
from PyQt5.QtGui import QIcon
from PyQt5.QtCore import pyqtSlot
 
class App(QMainWindow):
 
def __init__(self):
super().__init__()
self.title = 'PyQt5 textbox - pythonspot.com'
self.left = 10
self.top = 10
self.width = 400
self.height = 140
self.initUI()
 
def initUI(self):
self.setWindowTitle(self.title)
self.setGeometry(self.left, self.top, self.width, self.height)
 
# Create textbox
self.textbox = QLineEdit(self)
self.textbox.move(20, 20)
self.textbox.resize(280,40)
 
# Create a button in the window
self.button = QPushButton('Show text', self)
self.button.move(20,80)
 
# connect button to function on_click
self.button.clicked.connect(self.on_click)
self.show()
 
@pyqtSlot()
def on_click(self):
textboxValue = self.textbox.text()
QMessageBox.question(self, 'Message - pythonspot.com', "You typed: " + textboxValue, QMessageBox.Ok, QMessageBox.Ok)
self.textbox.setText("")
 
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = App()
sys.exit(app.exec_())

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PyQt5 window

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