Dynamic text like current time in prompt

Suppose I have this code like:

t=input(sprintf('%s\tInput temperature: ',datetime))

or

t_start=tic;
t=input(sprintf('%s\tInput temperature: ',seconds(toc(t_start))))

How do I get the datetime or the time elapsed to update continuously every second or whatever?

Can the input or the result of something like display("random text") be updated?

Thanks!

[Stephen23]

In theory you could use backspace to overwrite a line of text (which does not include a newline), but most likely you would be much better off using a proper GUI.

[Adam Danz]

Once input(__) is executed it can only be escaped by pressing the return key or ctrl+c and the prompt cannot be changed. You can use a GUI along with a timer.

[Salil Joshi]

Thanks Adam and Stephen (not sure why it is not letting me reply to Stephen though). I essentially want to display the current time or the time elapsed while waiting for the input, so that the user gets an idea of what stage the data acquisition is at. If I use the input function, then matlab waits for my input, so it cannot cycle back to keep updating the prompt.

Answer 1

[Adam Danz]

Here's a custom dialog box that requests input from the user and displays waiting time in seconds in the upper left corner. Timing stops when the figure is closed or when enter is pressed and the timing (duration) and user input (response) are returned.

Be cautious of the timer and tic/tic timing if you need a fine precision of temporal resolution.

% Build GUI (it will become visible at the end)
h.fig = figure('Position', [50 50 400 200],'Visible','off');
movegui(h.fig, 'center')
h.text = uicontrol(h.fig, 'Style', 'text', 'String', 'Enter something',...
    'Units','normalize', 'Position', [0,.75,1,.1], 'HorizontalAlignment', 'center',...
    'FontSize', 12);
h.inputbox = uicontrol(h.fig, 'Style', 'edit', 'Units', 'Normalize', ...
    'Position', [.2 .35 .6, .25],'FontName', 'FixedWidth','FontSize', 10);
h.button = uicontrol(h.fig, 'Style', 'pushbutton', 'String','Enter', ...
    'Units','Normalize','Position',[.4 .1 .2, .15], 'callback', @(h,~)uiresume(ancestor(h,'figure')));
h.timeStr = uicontrol(h.fig, 'Style', 'text', 'String', '0 sec',...
    'Units','normalize', 'Position', [.05,.75,.15,.1], 'HorizontalAlignment', 'center',...
    'FontName','FixedWidth','FontSize', 10);

% Create timer that updates the waiting time
h.timer = timer();
h.timer.ExecutionMode = 'fixedRate';
h.timer.Period = 1;  % seconds
h.timer.StartDelay = 1;
h.timer.TimerFcn = @(~,~)set(h.timeStr,'String',regexprep(h.timeStr.String,'^\d+','${num2str(str2double($0)+1)}'));
h.timer.StopFcn = @(timerHandle,~)delete(timerHandle);
h.fig.UserData.cleanup = onCleanup(@()stop(h.timer));

% turn on GUI, start timer, and wait for user
h.fig.Visible = 'on';
start(h.timer)
starttime = tic();
uiwait(h.fig) 

% % % % % % % % % % % % % % % % % %
%                                 %
%  Exectution is suspended until  %
%  user closes figure or presses  %
%  enter.                         %
%                                 %
% % % % % % % % % % % % % % % % % %


% Get waiting time
duration = toc(starttime); %seconds
% Get user's response
if isvalid(h.fig)
    % User pressed enter
    response = h.inputbox.String;
    close(h.fig) % close GUI
else
    % User closed fig
    response = '';
end

% Show results
fprintf('Wait time: %.2f sec.  Response: %s\n', duration, response)

[Salil Joshi]

Wow! Thanks! Excuse me while I go back and try to understand this code. Me sees lot of learnings in there!

:-)

[Salil Joshi]

I essentially want to display the current time or the time elapsed while waiting for the input, so that the user gets an idea of what stage the data acquisition is at. If I use the input function, then matlab waits for my input, so it cannot cycle back to keep updating the prompt.

[Adam Danz]

Exactly.... But see the link Walter Roberson shared.

The GUI I threw together shows the elapsed time. It can easily be changed to show the current time or a different type of duration. What are you imagining?

Answer 2

[Walter Roberson]

https://www.mathworks.com/matlabcentral/fileexchange/26471-setprompt-set-the-command-window-prompt

[Adam Danz]

That's cool! So many treasures in the FEX.

[Salil Joshi]

Thanks a bunch!

[Salil Joshi]

I am on R2020b, and it is whining about Unrecognized function or variable 'setPrompt'. Not sure if it needs some specific packages installed.

[Adam Danz]

Did you download the file in that link and add it to your Matlab path?