Run a function erverytime a new Datatip is selected (Callbacks for datatips)

Hello Matlab Community,

I would highly appreciate your help. I have the folowing problem:

I am creating a GUI, which is able to work with Datatips interactivly.

My goal is to create a function that run everytime a new datatip is selected. I want to do many things with that function, for exampel saving the datatips to an array or showing the last selected datapoint in the label below.

I am basicially talking about a callback for datatipselected.

That's why I am looking for a simple way to solve this. A pseudo code for this would be:

datatipselected = listener('selectingdatatips')

set(datatipselected, @run)

function run

% run code

end

[Mario Malic]

Not sure if I've understood correctly, so I'm posting this as a comment.

When the datatip is created, it's contained in the Children property of the graphic primitive such as line.

If you want to execute your callback when a new datatip is displayed in all graphic objects or a specific one.

dataTips = findall(groot, 'type', 'datatip'); % groot, axes handle, figure handle, any graphic object

You can use numel to get number of datatips, and if it changes, you can run your function.

[Philipp Schulz]

Hello Mario, thank you for your answer! How do I create a callback for a changing variable?

[Mario Malic]

See Interactivity sectíon https://ch.mathworks.com/help/matlab/ref/matlab.ui.figureappd-properties.html ButtonDownFcn probably should be the way to go. You should see examples with callbacks on uifigures/uiaxes first as it is not simple at first.

What do you mean by variable? I think you'll have to make your variable a property of the app so you can access it inside callback.

[Philipp Schulz]

This is what I tried to do after understanding your first answer. I created the variable dataTips in my property.

Then I was describing the variable app.dataTips in my startup Function as:

app.dataTips = findall(groot, 'type', 'datatip'); % groot, axes handle, figure handle, any graphic object

Now my problem is to define a callback function that runs after everytime the value app.dataTips changes. This way I have the chance to save the new datatip in the end of my array of all datatips. Do you know a way to create a function as such?

This would help me out a lot

Answer 1

[Adam Danz]

You can set the UpdateFcn of datacursormode. The function will execute every time a datatip is added. You can do anything you want within that function but you'll either need to reconstruct the original datatip or add new lines to the datatip.

Here are two demos that use custom update functions; you can run them to see how they work.

• Setting precision of datatip text
• Image in UIAxes

Here are demos that use custom update function to add a row of data to the datatip

• Add C value to surf object
• Add C value to scatter
• Add C value to pcolor
• Add a name to each line
• Add a date to each point
• Add parameter values to curves
• Add a 3rd value to X,Y info

Here's an example of using a ButtonDownFcn to create a datatip (use this only in cases where the option above is not supported).

• ButtonDownFcn to datatip
• ButtonDownFcn to pseudo-datatip that return values (go to method #5)

[Philipp Schulz]

Hello Adam,

thank you for this detailed answer. This helpeld me a lot solving my problem.

I have one more question. Once I enable datacursormode, my graph doesn't display datatips while hovering over them. This was working before activating datacursormode.

Is there a solution to it?

[Adam Danz]

Perhaps these threads may be helpful:

Image in uiaxes

Data tips in app designer