Creating a custom scrollbar widget in Python with Tkinter

Python Tkinter Custom Widgets and Themes: Exercise-12 with Solution

Write a Python program to build a custom scrollbar widget with a unique appearance, such as custom arrows or a background using Tkinter.

Sample Solution:

Python Code:

import tkinter as tk

class CustomScrollbar(tk.Frame):
    def __init__(self, master, **kwargs):
        super().__init__(master, **kwargs)
        self.canvas = tk.Canvas(self, bg="lightgray")
        self.scrollbar = tk.Scrollbar(self, orient="vertical", command=self.canvas.yview)
        self.canvas.config(yscrollcommand=self.scrollbar.set)

        self.scrollbar.pack(side="right", fill="y")
        self.canvas.pack(side="left", fill="both", expand=True)

        self.canvas.create_text(50, 50, text="Tkinter Exercises", fill="blue", font=("Arial", 14))

        # Create custom arrow buttons
        self.up_button = tk.Button(self, text="▲", command=self.scroll_up, font=("Arial", 12))
        self.down_button = tk.Button(self, text="▼", command=self.scroll_down, font=("Arial", 12))
        
        self.up_button.pack(side="top", fill="x")
        self.down_button.pack(side="bottom", fill="x")

        self.canvas.bind("", self.on_canvas_configure)

    def scroll_up(self):
        self.canvas.yview_scroll(-1, "units")

    def scroll_down(self):
        self.canvas.yview_scroll(1, "units")

    def on_canvas_configure(self, event):
        self.canvas.configure(scrollregion=self.canvas.bbox("all"))

if __name__ == "__main__":
    root = tk.Tk()
    root.title("Custom Scrollbar Example")
    custom_scrollbar = CustomScrollbar(root)
    custom_scrollbar.pack(fill="both", expand=True)
    root.mainloop()

Explanation:

In the exercise above -

• Create a CustomScrollbar class that inherits from "tk.Frame".
• Inside the "CustomScrollbar" class, create a canvas widget with a custom background color and a vertical scrollbar widget.
• The scrollbar command option allows you to configure the canvas to be scrollable.
• Add custom arrow buttons ("▲" and "▼") to scroll up and down. These buttons use the scroll_up and scroll_down methods to scroll the canvas.
• A custom rectangle and text are included on the canvas for demonstration purposes.
• Bind the <Configure> event to the "on_canvas_configure()" method, which updates the canvas scroll region when the window is resized.
• In the if name == "__main__": block, we create a Tkinter window and add the 'CustomScrollbar' widget to it.

Output:

Flowchart:

Python Code Editor:

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