Ring the system bell

A beep is the cheapest way to get a user’s attention — a flag for an invalid action, or a nudge that a long job has finished.

Beep with bell

bell() rings the system alert sound. Every widget has it, so call it on app or on whatever widget is at hand:

app.bell()

It plays the platform’s default alert; there is no volume or tone control.

Beep on a rejected action

The usual job: the user did something the app can’t accept, and you want to say so without a dialog. Beep, and put the reason on screen:

import ttkbootstrap as ttk

app = ttk.App(title="Bell", size=(320, 140))

amount = ttk.Entry(app)
amount.pack(padx=20, pady=(20, 4), fill="x")
message = ttk.Label(app, text="", bootstyle="danger")
message.pack()

def submit():
    if not amount.get().isdigit():
        app.bell()
        message.configure(text="Enter a number")
        return
    message.configure(text="")
    save(amount.get())

ttk.Button(app, text="Save", command=submit, bootstyle="primary").pack(pady=10)

app.mainloop()

The beep is the alert; the label is the explanation. A beep on its own tells the user something was wrong but not what — so pair it with something visible.

Note

Use it sparingly. A beep on every keystroke gets old fast, and a user who has silenced their system alert sound hears nothing at all — so never let a beep be the only way you report something.

Let a dialog beep for you

The shipped dialogs and toasts can ring the bell themselves. Messagebox error dialogs already do; ToastNotification takes alert=True:

ttk.ToastNotification(
    title="Export finished",
    message="Your report is ready.",
    alert=True,
).show_toast()

See also

• Mark a window busy — the other half of telling the user what is going on.

• Dialogs guide — Messagebox and Querybox, which beep on error for you.

• Validation guide — rejecting bad input before it reaches your handler.

Reference

• Toast — ToastNotification and its alert option.