Tkinteris the most commonly usedGUI (Graphical User Interface) library inPython. It is simple, easy to learn and comes built-in with Python. The name "Tkinter" comes from thetk interface, which is the underlying toolkit it uses.
To create multiple windows in a Tkinter application, we use the Toplevel widget. It functions similarly to a Frame, but it opens in a separate window with properties like a title bar, minimize, maximize and close buttons, just like the main application window.
What is the Toplevel Widget
- Toplevel is used to create a new independent window in a Tkinter application.
- It acts like the main window, having its own title bar, minimize, maximize and close buttons.
- It can be used for pop-ups, dialogs or additional windows in the application.
In this guide, we will explore how to open a new window when a button is clicked using two approaches:
- Using a function to create a new window
- Using a class-based approach for better modularity
Setting Up Tkinter
Tkinter comespre-installed withPython. However, on some Linux distributions likeUbuntu, wemay need to install it using:
sudo apt-get install python-tk
Creating a New Window Using a Function
This approach creates a new window when a button is clicked using the Toplevel widget. Here is the code:
Pythonfromtkinterimport*fromtkinter.ttkimport*# Create the main windowmaster=Tk()master.geometry("300x200")# Set window sizemaster.title("Main Window")# Function to open a new windowdefopen_new_window():new_window=Toplevel(master)# Create a new windownew_window.title("New Window")new_window.geometry("250x150")Label(new_window,text="This is a new window").pack(pady=20)# Create a label and a button to open the new windowLabel(master,text="This is the main window").pack(pady=10)Button(master,text="Open New Window",command=open_new_window).pack(pady=10)# Run the Tkinter event loopmaster.mainloop()Output:
Explanation:
- Toplevel(master): Creates a new window that is independent of the main window.
- new_window.title("New Window"): Sets the window title.
- new_window.geometry("250x150"): Defines the size of the new window.
- Label(...).pack(): Displays text inside the new window.
- command=open_new_window: Calls the function when the button is clicked.
Using a Class-Based Approach
This approach creates a dedicated class for new windows, making the code more reusable and organized. Here is the code:
Pythonfromtkinterimport*fromtkinter.ttkimport*# Class for creating a new windowclassNewWindow(Toplevel):def__init__(self,master=None):super().__init__(master)self.title("New Window")self.geometry("250x150")Label(self,text="This is a new window").pack(pady=20)# Create the main windowmaster=Tk()master.geometry("300x200")master.title("Main Window")Label(master,text="This is the main window").pack(pady=10)# Create a button to open the new window using the classbtn=Button(master,text="Open New Window")btn.bind("<Button>",lambdae:NewWindow(master))# Bind the eventbtn.pack(pady=10)# Run the Tkinter event loopmaster.mainloop()Output:
Explanation:
1. Class-Based Window (NewWindow)
- Inherits from Toplevel, so every instance behaves as a separate window.
- Defines window properties like title, size and a label inside the window.
2. Binding Click Event (bind()): Instead of usingcommand=, we use.bind("<Button>", lambda e: NewWindow(master)), meaning the button click event creates a new window.