Using Standard Dialogs

In this example, we’ll explore how to use various standard dialogs in PyQt5. Dialogs are highly beneficial when prompting users for tasks such as file selection, color choice, or font selection.

Listing 11 scripts/PYQT3/02_dialog_box/main.py

 # -*- coding: utf-8 -*-

 import sys
 from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QVBoxLayout, QWidget, QFileDialog, QLabel, QColorDialog, QFontDialog

 class MainWindow(QMainWindow):
     def __init__(self):
         super(MainWindow, self).__init__()

         layout = QVBoxLayout()

         # File Dialog
         self.label_file = QLabel(self)
         layout.addWidget(self.label_file)

         self.btn_open_file = QPushButton("Open File", self)
         self.btn_open_file.clicked.connect(self.open_file)
         layout.addWidget(self.btn_open_file)

         # Color Dialog
         self.label_color = QLabel("Selected Color", self)
         layout.addWidget(self.label_color)

         self.btn_open_color = QPushButton("Open Color Dialog", self)
         self.btn_open_color.clicked.connect(self.open_color)
         layout.addWidget(self.btn_open_color)

         # Font Dialog
         self.label_font = QLabel("Sample Text", self)
         layout.addWidget(self.label_font)

         self.btn_open_font = QPushButton("Open Font Dialog", self)
         self.btn_open_font.clicked.connect(self.open_font)
         layout.addWidget(self.btn_open_font)

         container = QWidget()
         container.setLayout(layout)
         self.setCentralWidget(container)

     def open_file(self):
         options = QFileDialog.Options()
         file_name, _ = QFileDialog.getOpenFileName(self, "Open File", "", "All Files (*);;Text Files (*.txt)", options=options)
         if file_name:
             self.label_file.setText(u"Selected file: {}".format(file_name))

     def open_color(self):
         color = QColorDialog.getColor()
         if color.isValid():
             self.label_color.setText("Selected Color: {}".format(color.name()))
             self.label_color.setStyleSheet("background-color: {}".format(color.name()))

     def open_font(self):
         font, ok = QFontDialog.getFont()
         if ok:
             self.label_font.setFont(font)

 if __name__ == '__main__':
     app = QApplication(sys.argv)
     mainWin = MainWindow()
     mainWin.show()
     sys.exit(app.exec_())

1. File Selection Dialog: A dialog that allows users to select a file.

   • The QFileDialog.getOpenFileName() method opens the file selection dialog.

   • When a user selects a file, the path of the chosen file is displayed on the label.

2. Color Selection Dialog: A dialog that enables users to select a color.

   • The QColorDialog.getColor() method opens the color selection dialog.

   • If the user selects a valid color, the label’s background is set to the chosen color, and the color’s name is displayed on the label.

3. Font Selection Dialog: A dialog where users can pick a font.

   • The QFontDialog.getFont() method opens the font selection dialog.

   • Upon font selection by the user, the label’s font changes to the chosen font.

The overall structure utilizes QVBoxLayout to align widgets from top to bottom, setting it as the central widget of the main window.