Since Python Tk widgets are classes, we can use inheritance to specialize widgets for our applications. A common use case is specifying themes for our widgets so that our GUI controls look consistent. In this tutorial, I’ll explain how to make themed Tk widgets.
from tkinter import * class ThemedFrame(Frame): def __init__(self, parent=None, **configs): Frame.__init__(self, parent, **configs) self.config(bg='Red', borderwidth=10) self.pack(expand=YES, fill=BOTH) class ThemedButton(Button): def __init__(self, parent=None, **configs): Button.__init__(self, parent, **configs) self.config(font=('Arial', 32)) self.pack() if __name__ == '__main__': frame = ThemedFrame() ThemedButton(frame, text='Quit', command=(lambda: sys.exit())) frame.mainloop()
The above code makes the following window. The background is red and the button has its font set to Arial 32. All of the ThemedButtons and ThemedFrames in this application will adhere to a consistent styling.
Making the ThemedFrame and ThemedButton are fairly straightforward. For ThemedFrame, we create a ThemedFrame class and have it extend Frame. Line 6 calls the Frame’s __init__ method and then we start our custom configuration on line 7. In this case, we set the frame’s background to red and give it a border that is 10 pixels thick. Then we pack the frame and set it’s expand and fill options so that the frame always resizes with the window.
ThemedButton follows the same pattern as ThemedFrame. The ThemedButton class extends Button. On line 12, we call Button’s __init__ method followed by configuration options on line 14. In this case, we set the button’s font to Arial 32. Then we call the pack() method.
The demonstration part is found on lines 18-21. We create a ThemedFrame object on line 19. It’s made the same way as a regular Frame. Line 20 makes a ThemedButton. The constructor is consistent with Button’s constructor, so we are free to pass attributes such as the text and callback handlers to the button. Finally, we call mainloop() on ThemedFrame. All of this works because ThemedButton and ThemedFrame are simply specialization of their parent classes.