使用 PyQt5 创建一个简单的浏览器

在本文中，我们将了解如何使用 PyQt5 创建一个简单的浏览器。

Web 浏览器是用于访问万维网上信息的软件应用程序。当用户从特定网站请求网页时，网络浏览器会从网络服务器检索必要的内容，然后将页面显示在屏幕上。

PyQt5是跨平台的 GUI 工具包，一组用于 Qt v5 的Python绑定。由于该库提供的工具和简单性，人们可以非常轻松地开发交互式桌面应用程序。

GUI Implementation steps :
1. Create a main window
2. Create a QWebEngineView object and add it as the central widget to the main window
3. Add Status bar to the main window
4. Create a toolbar and add navigation button and the line edit to show the url, below is hot the toolbar will look like

Back-End Implementation Steps :
1. Add update url action to QWebEngineView object when url is changed.
2. Inside the update url action change the url of url bar and change cursor position
3. Add another update title action to the QWebEngineView object when loading is finished
4. Inside the update title method update the title of the window as the page title
5. Add actions to the navigation buttons using the build-in functions of the QWebEngineView object for reload, back, stop and forward buttons
6. Add action to the home button and inside the action change the url to google.com
7. Add action to the line edit when return key is pressed
8. Inside the line edit action get the text and convert this text to the QUrl object and set the scheme if it is null and set this url to the QWebEngineView object

编程需要懂一点英语

下面是实现

Python3

# importing required libraries
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtWebEngineWidgets import *
from PyQt5.QtPrintSupport import *
import os
import sys
 
# creating main window class
class MainWindow(QMainWindow):
 
    # constructor
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
 
 
        # creating a QWebEngineView
        self.browser = QWebEngineView()
 
        # setting default browser url as google
        self.browser.setUrl(QUrl("http://google.com"))
 
        # adding action when url get changed
        self.browser.urlChanged.connect(self.update_urlbar)
 
        # adding action when loading is finished
        self.browser.loadFinished.connect(self.update_title)
 
        # set this browser as central widget or main window
        self.setCentralWidget(self.browser)
 
        # creating a status bar object
        self.status = QStatusBar()
 
        # adding status bar to the main window
        self.setStatusBar(self.status)
 
        # creating QToolBar for navigation
        navtb = QToolBar("Navigation")
 
        # adding this tool bar tot he main window
        self.addToolBar(navtb)
 
        # adding actions to the tool bar
        # creating a action for back
        back_btn = QAction("Back", self)
 
        # setting status tip
        back_btn.setStatusTip("Back to previous page")
 
        # adding action to the back button
        # making browser go back
        back_btn.triggered.connect(self.browser.back)
 
        # adding this action to tool bar
        navtb.addAction(back_btn)
 
        # similarly for forward action
        next_btn = QAction("Forward", self)
        next_btn.setStatusTip("Forward to next page")
 
        # adding action to the next button
        # making browser go forward
        next_btn.triggered.connect(self.browser.forward)
        navtb.addAction(next_btn)
 
        # similarly for reload action
        reload_btn = QAction("Reload", self)
        reload_btn.setStatusTip("Reload page")
 
        # adding action to the reload button
        # making browser to reload
        reload_btn.triggered.connect(self.browser.reload)
        navtb.addAction(reload_btn)
 
        # similarly for home action
        home_btn = QAction("Home", self)
        home_btn.setStatusTip("Go home")
        home_btn.triggered.connect(self.navigate_home)
        navtb.addAction(home_btn)
 
        # adding a separator in the tool bar
        navtb.addSeparator()
 
        # creating a line edit for the url
        self.urlbar = QLineEdit()
 
        # adding action when return key is pressed
        self.urlbar.returnPressed.connect(self.navigate_to_url)
 
        # adding this to the tool bar
        navtb.addWidget(self.urlbar)
 
        # adding stop action to the tool bar
        stop_btn = QAction("Stop", self)
        stop_btn.setStatusTip("Stop loading current page")
 
        # adding action to the stop button
        # making browser to stop
        stop_btn.triggered.connect(self.browser.stop)
        navtb.addAction(stop_btn)
 
        # showing all the components
        self.show()
 
 
    # method for updating the title of the window
    def update_title(self):
        title = self.browser.page().title()
        self.setWindowTitle("% s - Geek Browser" % title)
 
 
    # method called by the home action
    def navigate_home(self):
 
        # open the google
        self.browser.setUrl(QUrl("http://www.google.com"))
 
    # method called by the line edit when return key is pressed
    def navigate_to_url(self):
 
        # getting url and converting it to QUrl object
        q = QUrl(self.urlbar.text())
 
        # if url is scheme is blank
        if q.scheme() == "":
            # set url scheme to html
            q.setScheme("http")
 
        # set the url to the browser
        self.browser.setUrl(q)
 
    # method for updating url
    # this method is called by the QWebEngineView object
    def update_urlbar(self, q):
 
        # setting text to the url bar
        self.urlbar.setText(q.toString())
 
        # setting cursor position of the url bar
        self.urlbar.setCursorPosition(0)
 
 
# creating a pyQt5 application
app = QApplication(sys.argv)
 
# setting name to the application
app.setApplicationName("Geek Browser")
 
# creating a main window object
window = MainWindow()
 
# loop
app.exec_()

输出：