app.UIFigure = uifigure(); creates a new UIfigure window and the original app is not accessible through app.UIFigure

This is a continuation to Adam Danz's answer to:

https://in.mathworks.com/matlabcentral/answers/581585-why-a-linear-model-cannot-be-plotted-in-app-designer?s_tid=mlc_ans_men_view&mentions=true

While I get the plot by copyobj(), my app.uifigure is changed from app main window to the new window.

I can close the new app.uifigure, close(app.UIFigure) but the old one is still lost. So I cannot use some button down functions!

Answer 1

[Adam Danz]

@Mohd Aaquib Khan,

the first two lines of my answer in the thread you linked to were just to simulate app desgner. These two lines, copied below, can be removed from your implementation.

app.UIFigure = uifigure(); 
app.UIAxes = uiaxes(app.UIFigure); 

The code in the red box in the image in your question should appear like this

1. I've removed the first two lines
2. I've changes app.UIAxes to app.UIaxes2 since I think this the variable that stores your axes.

% Plot cfit object externally. 
a = linspace(0,10,10)';
b = linspace(0,20,10)';
[fitline,gof] = fit(a, b, 'poly1'); 
fig = figure('Visible','off');  % you may want to set this to "on" to see what's happening
ax = axes(fig); 
h = plot(fitline,a,b); 
% Copy content of temp axes to app designer
hApp = copyobj(h, app.UIAxes2); 
% You'll need to recreate the legend since it isn't independently copied
lh = legend(app.UIAxes2);
% Delete temp figure
delete(fig)

[Mohd Aaquib Khan]

Great, everything works well here except my name tag that you used 😄

you are right, there is no need to create a UIFigure!! My mistake for doing it without thinking.

One last doubt is do we have flexibility of adding more plots to this plot through more copyobj() in other callback functions by using hold on or by using other ways?

[Adam Danz]

Ha! Sorry, I updated the tag.

If I understood your follow-up question correctly, you can add as many graphics objects you want by following this template

ax = axes(fig); 
hold(ax,'on')
h1 = _____ 
h2 = _____
h3 = _____
% Copy content of temp axes to app designer
hApp = copyobj([h1,h2,h3] app.UIAxes2); 

However, it's much better to directly plot to your app axes by specifying the parent handle as the first option input:

plot(app.UIAxes2,____)

The reason you can't do this with fitline is because it uses a different version of plot() that does not support the optional parent argument.

[Mohd Aaquib Khan]

Dont mind the tag, I just meant it as a joke. Crazy enough, the tag you used was my brothers name so I was confused if I logged in from my brothers account!! 😂

Thanks for your solution.

Answer 2

[dpb]

If the AppDesigner app main figure were named just UIFigure in the auto-generated startup code function createComponents(app), then when you execute

app.UIFigure = uifigure();

you've overwritten the application app struct UIFigure handle with the new one and (as you've discovered) orphaned the original. DON'T DO THAT!!! :) You must use a different struct name when you create the second figure.

app.UIFigure2 = uifigure();

would work.

It's surprising the original app uifigure would not have some additional decoration in its name based on the name you gave the app when you created/saved it, but it appears must be given the symptoms you describe.

Show us what the beginning of the auto-generated createComponents(app) function looks like...

[Mohd Aaquib Khan]

Thank you for your answer.

Below is the createComponents(app):

% Component initialization
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 1390 752];
            app.UIFigure.Name = 'MATLAB App';
            app.UIFigure.ButtonDownFcn = createCallbackFcn(app, @UIFigureButtonDown, true);
            app.UIFigure.Scrollable = 'on';

            % Create UIAxes2
            app.UIAxes2 = uiaxes(app.UIFigure);
            title(app.UIAxes2, 'Title')
            

Also, I have tried app.UIFigure2 = uifigure(); but I get the error below.!!

Error using MyApp_16Sep/energyCycleNumberDropDownValueChanged

Unrecognized property 'UIFigure2' for class 'MyApp_16Sep'.

[dpb]

% Component initialization
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            ...

So, indeed, the main app figure is just UIFigure so you did overwrite that struct value when you created the second one. That clearly is a no-no; you never want to overwrite the created component handles; once you do that, they're lost forever unless you do a findobj search to find them again.

As for the second uifigure, try

app.UIFigure2=uifigure('Name','Figure 2','Syle','modal');

to differentiate it from the first...I don't know if there are any specific things done to prevent 'normal'secondary figures in AppDesigner or not; if this doesn't work, as per ususal, we would need to see the specific code in context.

I know you could create the secondary handle as a local variable in the callback function; doing that would, of course, mean you would have to do everything that was to be done within that function prior to leaving or that handle would also be orphaned.

[Mohd Aaquib Khan]

Still getting error with app.UIFigure2=uifigure('Name','Figure 2','Syle','modal');

Error using matlab.ui.internal.uifigureImpl
Can't find Syle property on the Figure class.


Error in uifigure (line 26)
window = matlab.ui.internal.uifigureImpl(varargin{:});

Error in myApp_16Sep/energyCycleNumberDropDownValueChanged (line 479)
app.UIFigure2=uifigure('Name','Figure 2','Syle','modal');

Anyway as you might have noticed, I was doing this to plot the fit curve as multiple plots were not possible in app till now. In 2023b we can do it I think

And I have changed the way I implement it now. I am using Y = feval( FitOutputVariable, X) and plot X,Y so it is sorted now.

So currently just pursuing it out of curiosity 😄

[dpb]

app.UIFigure2=uifigure('Name','Figure 2','Syle','modal');

'Style' is misspelled...read things carefully!!!

[Mohd Aaquib Khan]

Error using matlab.ui.internal.uifigureImpl
Can't find Style property on the Figure class.

Error in uifigure (line 26)
window = matlab.ui.internal.uifigureImpl(varargin{:});

Error in ITT_16Sep/energyCycleNumberDropDownValueChanged (line 479)
app.UIFigure2=uifigure('Name','Figure 2','Style','modal');

[Voss]

WindowStyle, not Style:

app.UIFigure2=uifigure('Name','Figure 2','WindowStyle','modal');

[dpb]

See uifigure -- old fogey memory ain't what it used to be, it's 'WindowStyle', not just 'Style'. Again, check docs, etc.,...don't rely on blind faith.

[Mohd Aaquib Khan]

Yea but the bigger problem is that it is not identifying UIFigure2

Error using MyApp_16Sep/energyCycleNumberDropDownValueChanged

Unrecognized property 'UIFigure2' for class 'MyApp_16Sep'.

[dpb]

>>  app.UIFigure=uifigure;
>> app.UIFigure2=uifigure('Name','Second','WindowStyle','modal');
>> app
app = 
  struct with fields:

     UIFigure: [1×1 Figure]
    UIFigure2: [1×1 Figure]
>> delete(app.UIFigure2)
>> delete(app.UIFigure)
>> clear app
>> 

works locally so syntax isn't the problem.

Would have to see the actual MyApp_16Sep/energyCycleNumberDropDownValueChanged callback function that is where the error is...there's something amiss inside it.