PyQt5技术问询：点击菜单栏对象时如何实现打开新窗口功能

Hey there! Let's get that menu bar action working to open a new window in your PyQt5 app. I've put together a complete, working version of your code with the feature implemented, plus breakdowns of the key parts so you understand how it all fits.

Complete Working Code #

import sys
from PyQt5.QtWidgets import QMainWindow, QApplication, QWidget, QAction, QLabel, QVBoxLayout
from PyQt5.QtGui import QIcon, QPixmap
from PyQt5 import QtCore

# Define the new window class
class NewWindow(QWidget):
    def __init__(self):
        super().__init__()
        self.initNewUI()

    def initNewUI(self):
        self.setWindowTitle("New Window")
        self.setGeometry(200, 200, 300, 200)
        
        # Add a sample label to the new window
        label = QLabel("This is your new window!", self)
        label.setAlignment(QtCore.Qt.AlignCenter)
        
        layout = QVBoxLayout()
        layout.addWidget(label)
        self.setLayout(layout)

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

    def initUI(self):
        self.left = 10
        self.top = 10
        self.width = 800
        self.height = 600
        self.setWindowTitle("Main Project Window")
        self.setGeometry(self.left, self.top, self.width, self.height)

        # Set up central widget and layout for the main window
        central_widget = QWidget()
        self.setCentralWidget(central_widget)
        main_layout = QVBoxLayout(central_widget)

        # Add your image (replace with your actual image path)
        pixmap = QPixmap("your_image.png")
        image_label = QLabel()
        image_label.setPixmap(pixmap.scaled(400, 300, QtCore.Qt.KeepAspectRatio))
        main_layout.addWidget(image_label)

        # Add your two labels
        label1 = QLabel("First Project Label", self)
        main_layout.addWidget(label1)
        label2 = QLabel("Second Project Label", self)
        main_layout.addWidget(label2)

        # Create menu bar and menu items
        menubar = self.menuBar()
        window_menu = menubar.addMenu("Windows")

        # Create the "Open New Window" action
        open_window_action = QAction(QIcon(), "Open New Window", self)
        open_window_action.setShortcut("Ctrl+N")  # Optional keyboard shortcut
        open_window_action.triggered.connect(self.launch_new_window)
        window_menu.addAction(open_window_action)

        # Optional: Add an exit action for convenience
        exit_action = QAction(QIcon(), "Exit", self)
        exit_action.setShortcut("Ctrl+Q")
        exit_action.triggered.connect(self.close)
        file_menu = menubar.addMenu("File")
        file_menu.addAction(exit_action)

        self.show()

    def launch_new_window(self):
        # Instantiate and show the new window
        # Store it as a class attribute to prevent garbage collection
        self.new_window = NewWindow()
        self.new_window.show()

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

Key Explanations #

• NewWindow Class: We create a separate class for the new window to keep code clean and modular. You can customize this class to add any widgets (buttons, text fields, etc.) your project needs.
• Menu Action Binding: The triggered.connect(self.launch_new_window) line links the menu item click to our function that opens the window. This is PyQt's signal-slot mechanism at work.
• Preventing Window Disappearance: By storing the new window as self.new_window (a class attribute), we avoid it being immediately garbage-collected (which would make it close right after opening). If you want multiple independent windows, you can store them in a list instead.
• Main Window Setup: I filled in the missing parts of your original initUI method to ensure the main window (with image and labels) displays correctly.

Extra Tips #

• Replace "your_image.png" with the actual path to your image file. If you don't need the image, just remove those lines.
• To add more menu items that open different windows, repeat the pattern: create a new window class, add a menu action, and bind it to a function that launches that window.
• If you need communication between the main window and new windows, use PyQt's custom signals and slots to pass data back and forth.

内容的提问来源于stack exchange，提问作者A Damian