Chapter 3 - Create an empty QMainWindow

You can now think of presenting your data in a UI. A QMainWindow provides a convenient structure for GUI applications, such as a menu bar and status bar. The following image shows the layout that QMainWindow offers out-of-the box:

QMainWindow layout

In this case, let your application inherit from QMainWindow, and add the following UI elements:

  • A “File” menu to open a File dialog.

  • An “Exit” menu close the window.

  • A status message on the status bar when the application starts.

In addition, you can define a fixed size for the window or adjust it based on the resolution you currently have. In the following snippet, you will see how window size is defined based on available screen width (80%) and height (70%).

Note

You can achieve a similar structure using other Qt elements like QMenuBar, QWidget, and QStatusBar. Refer the QMainWindow layout for guidance.

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from PySide2.QtCore import Slot, qApp
from PySide2.QtGui import QKeySequence
from PySide2.QtWidgets import QMainWindow, QAction


class MainWindow(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        self.setWindowTitle("Eartquakes information")

        # Menu
        self.menu = self.menuBar()
        self.file_menu = self.menu.addMenu("File")

        # Exit QAction
        exit_action = QAction("Exit", self)
        exit_action.setShortcut(QKeySequence.Quit)
        exit_action.triggered.connect(self.close)

        self.file_menu.addAction(exit_action)

        # Status Bar
        self.status = self.statusBar()
        self.status.showMessage("Data loaded and plotted")

        # Window dimensions
        geometry = qApp.desktop().availableGeometry(self)
        self.setFixedSize(geometry.width() * 0.8, geometry.height() * 0.7)

Try running the script to see what output you get with it.