Building a Custom Web Browser in PyQt5 - A Step-by-Step Guide with Code

Introduction:

In this tutorial, we will be building a custom web browser using the PyQt5 library and the QWebEngineView class. PyQt5 is a set of Python bindings for the Qt libraries, and QWebEngineView provides a widget for displaying web pages. We will be using the QMainWindow class to create the main window for our browser, and the QLineEdit, QToolBar, and QPushButton classes for the address bar, toolbar, and buttons.

 

Step 1: Setting up the Environment

• Before we begin coding our browser, we need to make sure we have the necessary libraries installed. The PyQt5 library can be installed using the pip package manager with the command "pip install PyQt5".

 

Step 2: Creating the Browser Class

import sys from PyQt5.QtCore import QUrl,QFile, QTextStream from PyQt5.QtWidgets import QApplication, QMainWindow, QLineEdit, QToolBar, QPushButton from PyQt5.QtWebEngineWidgets import QWebEngineView,QWebEnginePage   class Browser(QMainWindow):     def __init__(self):         super().__init__()         self.setWindowTitle("My Browser")                 self.view = QWebEngineView(self)         self.setStyleSheet(self.read_stylesheet())       def read_stylesheet(self):

 

• In the above code, we import the necessary libraries and create a new class called "Browser" that inherits from the QMainWindow class.
• In the init method, we create an instance of the QWebEngineView class and set the window title of our main window.
• We also create a method called read_stylesheet that will read the stylesheet file and set it for the browser.

 

Step 3: Adding the Address Bar and Toolbar

# Create the address bar         self.address_bar = QLineEdit()         self.address_bar.returnPressed.connect(self.load_url)           # Create the toolbar         self.toolbar = QToolBar()         self.toolbar.addWidget(self.address_bar)

 

• In the above code, we create the address bar using the QLineEdit class and add it to a toolbar created with the QToolBar class.
• We also connect the returnPressed signal of the address bar to a method that will load the URL entered by the user.

 

Step 4: Adding the Back and Forward Buttons

# Create back button     self.back_button = QPushButton(""<")     self.back_button.clicked.connect(self.view.back)     self.toolbar.addWidget(self.back_button)       # Create forward button     self.forward_button = QPushButton(">")     self.forward_button.clicked.connect(self.view.forward)     self.toolbar.addWidget(self.forward_button)       self.addToolBar(self.toolbar)

 

·       In the above code, we create two buttons, one for going back and one for going forward, using the QPushButton class.

·       We also connect the clicked signal of these buttons to the back() and forward() methods of the QWebEngineView class.

·       We add the toolbar to the main window

 

Step 5: Loading the URL

def load_url(self):         url = self.address_bar.text()         self.view.load(QUrl(url))

 

• In the above code, we create a method called load_url that will take the text from the address bar and use it to load a web page using the load() method of the QWebEngineView class.

 

Step 6: Updating the Back and Forward Buttons

def update_back_forward_buttons(self):         self.back_button.setEnabled(self.view.page().action(QWebEnginePage.Back).isEnabled())         self.forward_button.setEnabled(self.view.page().action(QWebEnginePage.Forward).isEnabled())

 

• In the above code, we create a method called update_back_forward_buttons that will be called when the web page is finished loading. This method will update the enabled state of the back and forward buttons based on whether the back() and forward() actions are available.

 

Step 7: Styling the Browser using a CSS File

• Create a stylesheet file called "styles.css" that can be used to customize the look and feel of our browser.
• In the read_stylesheet method, read the stylesheet file and set it using the setStyleSheet() method of the QMainWindow class.

 

Step 8: Running the Application

app = QApplication(sys.argv) browser = Browser() browser.show() sys.exit(app.exec_())

 

• In the above code, we create an instance of the QApplication class and our Browser class
• We call the show() method of the Browser class to display the main window.

 

Complete Code:

import sys from PyQt5.QtCore import QUrl,QFile, QTextStream from PyQt5.QtWidgets import QApplication, QMainWindow, QLineEdit, QToolBar, QPushButton from PyQt5.QtWebEngineWidgets import QWebEngineView,QWebEnginePage   class Browser(QMainWindow):     def __init__(self):         super().__init__()         self.setWindowTitle("My Browser")                 self.view = QWebEngineView(self)         self.setStyleSheet(self.read_stylesheet())       def read_stylesheet(self):         file = QFile("styles.css")         # Create the address bar         self.address_bar = QLineEdit()         self.address_bar.returnPressed.connect(self.load_url)           # Create the toolbar         self.toolbar = QToolBar()         self.toolbar.addWidget(self.address_bar)           # Create back button         self.back_button = QPushButton("<")         self.back_button.clicked.connect(self.view.back)         self.toolbar.addWidget(self.back_button)           # Create forward button         self.forward_button = QPushButton(">")         self.forward_button.clicked.connect(self.view.forward)         self.toolbar.addWidget(self.forward_button)           self.addToolBar(self.toolbar)           self.view.load(QUrl("http://www.google.com"))         self.setCentralWidget(self.view)         self.view.loadFinished.connect(self.update_back_forward_buttons)             def load_url(self):         url = self.address_bar.text()         self.view.load(QUrl(url))             def update_back_forward_buttons(self):         self.back_button.setEnabled(self.view.page().action(QWebEnginePage.Back).isEnabled())         self.forward_button.setEnabled(self.view.page().action(QWebEnginePage.Forward).isEnabled())   app = QApplication(sys.argv) browser = Browser() browser.show() sys.exit(app.exec_())

 

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