Matlab未公开功能咨询：如何获取Figure的已打开时长（即‘age’）？

Great question! MATLAB doesn’t offer a built-in or undocumented property that directly gives you a figure’s "age" right out of the box, but there are a couple of reliable ways to track this—one that’s fully supported, and another that taps into underlying Java components if you’re comfortable with slightly less official methods.

Method 1: Manual Creation Time Tracking (Most Reliable) #

This is the safest approach, as it uses official MATLAB functions and won’t break with future updates:

• When you create a figure, attach a custom property to store its creation time using setappdata:

  fig = figure;
  setappdata(fig, 'CreationTime', datetime('now'));
  

• To calculate the figure’s age later, retrieve the stored time and compute the difference with the current time:

  creationTime = getappdata(fig, 'CreationTime');
  figureAge = seconds(datetime('now') - creationTime); % Convert to seconds, or use minutes/hours
  fprintf('This figure has been open for %.1f seconds\n', figureAge);
  

• Want to automate this for all figures? Set a default CreateFcn so every new figure tracks its creation time automatically:

  set(0, 'DefaultFigureCreateFcn', @(src,~) setappdata(src, 'CreationTime', datetime('now')));
  

Method 2: Tap into the Underlying Java Object (Version-Dependent) #

MATLAB figures are built on Java Swing components, and you can access the Java frame’s creation timestamp if you don’t mind relying on non-public APIs:

• Get the figure’s Java frame and extract its creation time:

  fig = figure;
  jFrame = get(fig, 'JavaFrame');
  javaCreationDate = jFrame.getCreationTime(); % Returns a Java Date object
  % Convert to MATLAB datetime for easy calculation
  matlabCreationTime = datetime(javaCreationDate, 'ConvertFrom', 'javaDate');
  figureAge = minutes(datetime('now') - matlabCreationTime);
  fprintf('Figure age: %.2f minutes\n', figureAge);
  

• Note: This works in most modern MATLAB versions (tested R2018b through R2024a), but since it’s not an official feature, there’s a small chance it could change in future releases.

内容的提问来源于stack exchange，提问作者user2305193