CODEWITHSUNDEEP
cocoa
Debajit
Debajit

Reputation: 47111

Cocoa: Measure time between keypresses?

I'm trying to write an app where I need to accept keypresses, and call a function whenever the user has stopped typing (or when there is a specified delay between keystrokes).

How do I measure the time between two keystrokes?

Upvotes: 2

Views: 2668

Answers (5)

Amaan Durrani
Amaan Durrani

Reputation: 11

I think you should use threads for this. Create thread for keys and in each thread you can calculate time between key strokes. For more explanation you watch my video for this exact solution.

https://www.youtube.com/watch?v=sDGYM8LeZh8

See the code below:

import keyboard # keyboard library
import string   # string for capturing keyboard key codes
import time     # for capturing time

from threading import * # threads for keypresses

# get the keys
keys = list(string.ascii_lowercase)

# key listener
def listen(key):
    while True:
        global timeda   # global variable for storing time for 1st keypress
        global newda    # global variable for storing time for next keypress

        keyboard.wait(key)  # when key is presses

        # check if variables are defined
        try:
            timeda
            newda

        # this will run for the first keypress only so assign initial time to variable

        except NameError:
            timeda = time.time()
            newda  = time.time()
            print("First key is pressed at "+str(round(newda,2)))
            print('\n==========\n')

        # for all keypresses except for the first will record time here
        else:
            newda = time.time()         # assign time for next keypressed
            newtime = newda - timeda    # get difference between two keys presses

            # just to test time of first keypress
            print("Previous keypress was at "+str(round(timeda,2)))

            # just to test time of next keypress
            print("Current keypress is at "+ str(round(newda,2)))

            # convert time into seconds
            newtime = newtime % 60

            print("Difference between two keypresses is "+str(round(newtime,2)))
            print('\n==========\n')     # need some space for printing difference 
            timeda = time.time()

# creating threads for keys and assigning event and args 
threads = [Thread(target=listen, kwargs={'key':key}) for key in keys]

# calling each thread
for thread in threads:
    thread.start()


# thats it

Upvotes: 0

stefanB
stefanB

Reputation: 79810

  • You could setup timer to execute something X amount of time after user stopped typing, then restart the time each time user type something - so it will delay timer expiry.

Not sure how computationally intensive this is, if it is easy to reset timeout on timer.

  • Optionally you could start timer on last keystroke for X amount of time. On expiry you could check timestamp of last keystroke, which you saved on last keystroke, then you can either restart timer starting with (timeout - last keystroke time) amount of time. On expiry do the check again. Then, on each keystroke if timer is running only update timestamp of last keystroke ...

Upvotes: 0

David Weiss
David Weiss

Reputation: 1782

Something like this:

NSDate *start = [NSDate date];
// do the thing you are timing
NSDate *stop = [NSDate date];

NSTimeInterval duration = [start timeIntervalSinceDate:stop];

Upvotes: 8

Mike Abdullah
Mike Abdullah

Reputation: 15003

Probably a better approach is to pick up the NSEvent associated with each keypress and compare the difference in their -timestamp property.

Upvotes: 5

Peter Hosey
Peter Hosey

Reputation: 96333

Get the current time, then subtract the previous current time. See -[NSDate timeIntervalSinceDate:].

Upvotes: 2

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