add a number to the legend

Hi,

I want to add a legend to the plot so that each time the button in GUI is pressed the legend will show a string with corresponding number.

I want to work it like this:

First plot: Sandwich panel(1), second plot: Sandwich panel(2), etc...

My current code:

semilogx(f,TL,'DisplayName','Sandwich panel');
grid on
ylabel('Transmission Loss [dB]');
xlabel ('Frequency')
xlim([80 10000])
title('Transmission Loss')
legend('-DynamicLegend','location','best')
hold all

Thanks,

Dominika

Answer 1

[Sara]

legend(['Sandwich panel(',num2str(put_number_here),')'])

or you could use sprintf.

[Dominika]

Thanks for an answer Sara but I want Matlab to do it automatically, each press of the button in GUI will produce a string 'Sandwich panel' with a counting number.

[Sara]

Dominika, do you mean you need a way to count how many times the button has been pressed? In that case, you'll have to create a variable that is incremented any time you press the button, set it to zero in the opening_funct of the gui, and increment it in the pushbutton callback. Make sure to have:

guidata(hObject, handles);

at the end of the callback. Does this help?

Answer 2

[David Sanchez]

Continuing with Sara's comment:

In your callback function,

N_pushes = N_pushes + 1;

my_str = sprintf('Sandwich panel %g',N_pushes);

legend(my_str);

[Dominika]

It seems to be exactly what I need but how can I get the handle of N_pushes from Opening function to the button Callback?

Thanks!

[Sara]

You set it in the opening function but not as a stand-alone variable, but rather as a member of handles. so it'll be something like: handles.N_pushes = 0; in the opening function And accordingly, you increment handles.N_pushes.

[Dominika]

I put in the Opening Function:

handles.N_pushes = 0;

and in the Callback Function:

handles.N_pushes = handles.N_pushes + 1;

my_str = sprintf('Sandwich panel %g',handles.N_pushes); 

semilogx(f,TL,'DisplayName','my_str'); 

grid on
ylabel('Transmission Loss [dB]');
xlabel ('Frequency')
xlim([80 10000])
title('Transmission Loss')
legend('-DynamicLegend','location','best')
hold all

guidata(hObject, handles);

The error: Reference to non-existent field 'N_pushes'.

Could you tell me what did I do wrong?

Thanks!

[Sara]

Do you have the instruction

guidata(hObject, handles);

at the end of EACH callback, including the opening function? Otherwise the variables you add to handles are not saved.

[Dominika]

Works like a charm.

Thank you so much.

Have a nice day!