I need to write a code to record time stamps each time mouse is clicked. The following code works but only for 13 iteration or 13 presses. Is there a simpler way to do so?

 for i = 1:length('ButtonDownFcn')
    waitforbuttonpress
    tt(i) = now;
 end

Answer 1

[Walter Roberson]

length('ButtonDownFcn') asks for the length of the string 'ButtonDownFcn' which happens to be 13 characters.

How many presses would you like recorded, and how would you like the user to indicate that they want to stop clicking?

[Dushyant Dhundara]

It can be any number of presses depending on the user , that is why there is not a set number. And they can just press stop or something I guess, may be I should use a GUI?? I guess I though that 'ButtonDownFcn' was recording the number of mouse clicks

[Walter Roberson]

A GUI might make sense. You can use a ButtonDownFcn callback or a WindowButtonDownFcn callback.

[Dushyant Dhundara]

I am using the following code, but it doesn't save the timestamp as a variable

format long g
S.hFig = figure('KeyPressFcn',@youPressedSomething,...
            'menu','none',...
            'pos',[400 400 320 50]);
KeyPressFcn = ' '; %  ButtonDownFcn
S.th = uicontrol('Style','text','Position',[10 10 300 30],...
              'String','Hit Space Bar to record Time Stamp');
set(S.hFig,'KeyPressFcn', @(~,~) disp(now));
timeStamp = [];
for i = 1:length(timeStamp)
  timeStamp{i} = now;
end

[Walter Roberson]

function [getter, S] = timestamps

    timeStamp = [];

    function recordtime(~, ~)
      timeStamp(end+1) = now;
    end

    function ts = getterfcn(varargin)
      if nargin > 0
        timeStamp = [];
      end
      ts = timeStamp;
    end

    S.hFig = figure('menu','none',...
                'pos', [400 400 320 50]);

    S.th = uicontrol('Style', 'text', 'Position', [10 10 300 30], ...
                  'String', 'Push button to record Time Stamp');
    S.bh = uicontrol('Style', 'push', 'Position', [10 50 30 30], ...
                  'String', 'Timestamp', 'Callback', @recordtime);

    getter = @getterfcn;
  end

This code creates and configures a figure with a text area and a push button, and the code returns a function handle and a structure of handles.

When the pushbutton is clicked, the timestamp is recorded in the shared variable timeStamp.

Shared variables are not normally accessible outside the function that creates them. I could have programmed it without a shared variable, using other techniques, but it would not have been as self-contained.

I mentioned the function returns a function handle. Call that function handle to get the current list of timestamps. Also, if you pass any argument (with any value) to the function handle then the timestamp list will be emptied.

The structure of handles that is returned can be used to delete the figure once it is no longer needed. Or it can be used to disable the pushbutton if it is not required for a period.

Example of use:

[getter, S] = timestamps();
getter(true);  %clear timestamp list
duration = datenum([0, 0, 0, 0, 0, 15]);  %15 seconds

starttime = now; endtime = starttime + duration;
while now < endtime
  pause(0.01);
end

abs_time_of_clicks = getter();
rel_time_of_clicks = abs_time_of_clicks - starttime;

[Dushyant Dhundara]

This code works for the allotted duration time. If I had to use such a method, it can be easily done for the code I had posted initially by setting the number of loops

[Walter Roberson]

It is an example of the use of the code, showing the flexibility of the approach. Basically, you initialize,

[getter, S] = timestamps();
getter(true);  %clear timestamp list

and then you do whatever needs to be done to decide when to stop. When you figure out that you want to stop,

abs_time_of_clicks = getter();

will return the timestamps. You can then manipulate them such to find relative times, like

   rel_time_of_clicks = abs_time_of_clicks - abs_time_of_clicks(1);
   dv = datevec(rel_time_of_clicks);
   click_secs = dv(:,5)*60 + dv(:,6);   %seconds, assuming less than 1 hour

If this is not acceptable, you will need to tell us exactly how you want the interface to work: how should the user click, how should the user indicate they want to stop, how should your code initialize (reset) the list, how should your code retrieve the list, should absolute or relative times be returned, what units should the returned times be in, do you need an action (other than recording the timestamp) for each click, do you need to be able to retrieve the timestamps before the user has indicated to stop, should asking for the list of timestamps automatically clear out the existing list of timestamps? Do the routine names need to be anything in particular? Is it okay to have the initialization be a function, or does it have to be a script ?

[Dushyant Dhundara]

Thanks for your input. I think the question I had posted originally is pretty clear what I am asking. I do not require any of the functionalities you have listed. Anyways thanks for the help

[Walter Roberson]

S.hFig = figure('menu','none',...
            'pos',[400 400 320 50]);
S.th = uicontrol('Style','text','Position',[10 10 300 30],...
              'String','Hit Space Bar to record Time Stamp');
timestamp = [];
set(S.hFig,'KeyPressFcn', @(~,~) assignin('base', 'timestamp(end+1)', now));

Caution: this will only work as a script, not within a function.

There is no specific way to stop: clicks will be recorded as long as the user cares to make them. You can access the timestamp variable any time after it is initialized. The user is not given any method to indicate that they want to stop, or that any further action should be taken, because that is a feature you have indicated you do not require.