Set the focus on the desired widget in tkinter

Setting the focus on a specific widget in tkinter is crucial when you want to direct the user's attention to or start interaction with a particular input field or control immediately after launching the application. For instance, you might want an entry field to be ready for typing as soon as a form window opens.

Here's a tutorial on how to set the focus on a desired widget using tkinter:

Setting Focus on a Widget in Tkinter Tutorial:

1. Import Required Libraries:

import tkinter as tk

2. Create the Main Application Window:

root = tk.Tk()
root.title("Focus Tutorial")

3. Create Several Widgets: Let's create a couple of Entry widgets and a Button widget for demonstration:

label1 = tk.Label(root, text="First Entry:")
label1.pack(pady=10)

entry1 = tk.Entry(root)
entry1.pack(pady=10)

label2 = tk.Label(root, text="Second Entry:")
label2.pack(pady=10)

entry2 = tk.Entry(root)
entry2.pack(pady=10)

submit_button = tk.Button(root, text="Submit")
submit_button.pack(pady=20)

4. Set Focus on a Desired Widget: Now, let's say you want to set the focus on entry2 as soon as the window opens. Use the focus_set() method:

entry2.focus_set()

5. Run the Main Loop:

root.mainloop()

Complete Code:

import tkinter as tk

root = tk.Tk()
root.title("Focus Tutorial")

label1 = tk.Label(root, text="First Entry:")
label1.pack(pady=10)

entry1 = tk.Entry(root)
entry1.pack(pady=10)

label2 = tk.Label(root, text="Second Entry:")
label2.pack(pady=10)

entry2 = tk.Entry(root)
entry2.pack(pady=10)

submit_button = tk.Button(root, text="Submit")
submit_button.pack(pady=20)

entry2.focus_set()

root.mainloop()

Upon running the above code, you'll notice that even though entry1 appears first, the focus is set on entry2, making it ready for user input immediately.

Note: In some situations, especially when dealing with more complex layouts, you may want to set the focus inside a widget's callback or after the window is fully drawn to ensure it works correctly. Using the after method to delay focus-setting can be useful in such cases:

def set_focus_on_widget():
    entry2.focus_set()

root.after(100, set_focus_on_widget)

Python Tkinter focus_set method example: The focus_set() method in Tkinter is used to set the input focus to a particular widget. This means that the keyboard input will be directed to the specified widget.
```
import tkinter as tk

root = tk.Tk()

entry = tk.Entry(root)
entry.pack()

# Set focus to the entry widget
entry.focus_set()

root.mainloop()
```

Setting the focus on an entry widget in Tkinter:

import tkinter as tk

root = tk.Tk()

entry = tk.Entry(root)
entry.pack()

# Set focus to the entry widget
entry.focus_set()

root.mainloop()

Python Tkinter focus_get and focus_set methods:

import tkinter as tk

def switch_focus():
    if entry1.focus_get() == entry1:
        entry2.focus_set()
    else:
        entry1.focus_set()

root = tk.Tk()

entry1 = tk.Entry(root)
entry1.pack()

entry2 = tk.Entry(root)
entry2.pack()

button = tk.Button(root, text="Switch Focus", command=switch_focus)
button.pack()

root.mainloop()

Change focus between widgets in Tkinter:

import tkinter as tk

def switch_focus():
    if entry1.focus_get() == entry1:
        entry2.focus_set()
    else:
        entry1.focus_set()

root = tk.Tk()

entry1 = tk.Entry(root)
entry1.pack()

entry2 = tk.Entry(root)
entry2.pack()

button = tk.Button(root, text="Switch Focus", command=switch_focus)
button.pack()

root.mainloop()