File Picker in PyQt: A Comprehensive Python GUI Tutorial (Lesson 14)

In this tutorial, we will learn how to open files using a file picker dialog in a PyQt-based Python GUI application. This functionality can be useful when you want to allow users to select and open files from their computer.

To get started, make sure you have PyQt installed. You can install PyQt using pip:

pip install PyQt5

Next, create a new Python script and import the necessary modules:

import sys
from PyQt5.QtWidgets import QApplication, QFileDialog, QMainWindow, QPushButton

Now, create a main window class that will contain a button to open the file picker dialog:

class FilePickerWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        self.init_ui()

    def init_ui(self):
        self.setWindowTitle('File Picker Example')
        self.setGeometry(100, 100, 400, 200)

        self.btn = QPushButton('Open File', self)
        self.btn.setGeometry(150, 80, 100, 30)
        self.btn.clicked.connect(self.open_file)

    def open_file(self):
        file_dialog = QFileDialog()
        file_dialog.setFileMode(QFileDialog.ExistingFile)
        file_dialog.setNameFilter('All Files (*.*)')

        if file_dialog.exec_():
            file_path = file_dialog.selectedFiles()[0]
            print(f'Selected file: {file_path}')

In the open_file method, we create a QFileDialog instance and set the file mode to QFileDialog.ExistingFile, which allows the user to select an existing file. We then set the name filter to show all files (All Files (*.*)).

When the user selects a file and clicks the "Open" button in the file picker dialog, the selectedFiles() method returns a list of selected file paths. We extract the first file path from the list and print it to the console.

Finally, create an application instance and show the main window:

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

Now, when you run the script, a window will appear with a button labeled "Open File". Clicking this button will open a file picker dialog, allowing you to select a file. The selected file path will be printed to the console.

That’s it! You have successfully implemented file opening functionality using a file picker in a PyQt-based Python GUI application. I hope you found this tutorial helpful. Thank you for reading!