How can I detect long mouse clicks with tkinter?-CodePudding

I want to detect a long mouse click using tkinter. How can I do that? The <Button-1> doesn't help at all.

CodePudding user response：

You can create a binding for both the button press (<ButtonPress-1>) and button release (<ButtonRelease-1>). Save the time that the press happened and then compute the delay when the release happened.

Or, depending on what you mean by "detect", you can schedule a job to run when the button is clicked, and then cancel the job if the button is released before the timeout.

CodePudding user response：

Here's code demonstrating how to "detect" when a long mouse click has occurred (the second thing @Bryan Oakley mentioned). It accomplished the feat by "binding" various callback functions to different tkinter events, including a virtual one I made up named '<<LongClick-1>>'.

It will display a window with a Label in it indicating the mouse's click status. If you click and hold the mouse button down long enough (2 secs), the on_long_click() event handler function will called and change the text on the Label accordingly.

import tkinter as tk
from tkinter.constants import *
from time import perf_counter as cur_time


LONG_CLICK = 2.0  # Seconds.
start_time = None
timer = None
CHECKS_PER_SECOND = 100  # Frequency that a check for a long click is made.

root = tk.Tk()
root.geometry('100x100')

def on_button_down(event):
    global start_time, timer

    label.config(text='Click detected')
    start_time = cur_time()
    timing = True
    timer = check_time()


def check_time():
    global timer

    if (cur_time() - start_time) < LONG_CLICK:
        delay = 1000 // CHECKS_PER_SECOND  # Determine millisecond delay.
        timer = root.after(delay, check_time)  # Check again after delay.
    else:
        root.event_generate('<<LongClick-1>>')
        root.after_cancel(timer)
        timer = None


def on_button_up(event):
    global timer

    if timer:
        root.after_cancel(timer)
        timer = None
        label.config(text='Waiting')


def on_long_click(event):
    label.config(text='Long click detected')


label = tk.Label(root, text='Waiting')
label.pack(fill=BOTH, expand=1)

root.bind('<ButtonPress-1>', on_button_down)
root.bind('<ButtonRelease-1>', on_button_up)
root.bind('<<LongClick-1>>', on_long_click)

root.mainloop()

Although it's not particularly exciting, here's a screenshot of it running: