Dialog UI and sprintf creating unnecessary new lines

I am trying to create a dialog box and set the text value inside it using the uicontrol function. The actual text I use is a combination of 3 different string variables that I combine using sprintf.

ui_message = sprintf('%s\n%s\n%s',line_1,line_2,line_3)

However, in cases where line_2 is a string that is longer than the dialog box itself, it moves down onto the next line (which is desirable) but it also adds a new line between line_1 and line_2!

So where I want my results to appear in the ui dialog box as (self explanatory what corresponds to which "line_N" variable"):

"Hello"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"Goodbye"

For some reason I get

"Hello"

"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"Goodbye"

instead. If the AAAAA string overlaps two lines, then there are two spaces between the first and second lines.

[Walter Roberson]

Send a cell array of character vectors instead of using \n to separate the parts ?

If somehow you have a character vector with embedded newlines then you can use strsplit() on it.

[Dimitry Ignatov]

I don't know how the following fixes it but it looks like this works, strsplit helped. I did:

ui_mess = sprintf('%s\n%s\n%s',line_1,line_2,line_3)
ui_mess = strsplit(ui_mess,'\n')

uicontrol( . . . 'String',ui_mess)

I'll take it.

[Walter Roberson]

Unless something else outside your control is generating the initial ui_mess, I would just have directly coded

ui_mess = {line_1, line_2, line_3};

Answer 1

[Binbin Qi]

The following is my code. It is can work normally. Can you give your code here?

 function mydialog(line1,line2,line3)
if nargin == 0
    line1 = 'Hello';
    line2 = 'AAAAAAAAAAAAA';
    line3 = 'Goodbye';
end
    ui_message = @(line_1,line_2,line_3)sprintf('%s\n%s\n%s',line_1,line_2,line_3);
    d = dialog('Position',[300 300 250 150],'Name','My Dialog');

    uicontrol('Parent',d,...
               'Style','text',...
               'Position',[20 80 210 40],...
               'String',ui_message(line1,line2,line3));

    uicontrol('Parent',d,...
               'Position',[85 20 70 25],...
               'String','Close',...
               'Callback','delete(gcf)');
end

[Walter Roberson]

you need line2 to be longer.

I was able to reproduce the problem on my system.

[Binbin Qi]

ok, you are right. I suggest you can use listbox instand of text

function mydialog(line1,line2,line3)
if nargin == 0
    line1 = 'Hello';
    line2 = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
    line3 = 'Goodbye';
end
    ui_message = @(line_1,line_2,line_3)sprintf('%s\n%s\n%s',line_1,line_2,line_3);
    d = dialog('Position',[300 300 550 500],'Name','My Dialog');

    uicontrol('Parent',d,...
               'Style','listbox',...
               'Position',[20 200 210 140],...
               'String',ui_message(line1,line2,line3));

    uicontrol('Parent',d,...
               'Position',[85 20 70 25],...
               'String','Close',...
               'Callback','delete(gcf)');
end

[Dimitry Ignatov]

A listbox is too far from what I need, it implies the user needs to make a selection of some kind. I just need to display strings of undetermined (variable) length (I have some code that sizes the dialog box based on how many characters it needs to display).

[Binbin Qi]

ok ,I think @Walter Roberson is right, you can use cell, like the following code.

function mydialog(line1,line2,line3)
if nargin == 0
    line1 = 'Hello';
    line2 = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
    line3 = 'Goodbye';
end
    ui_message = @(line_1,line_2,line_3){line_1,line_2,line_3};
    d = dialog('Position',[300 300 550 500],'Name','My Dialog');

    uicontrol('Parent',d,...
               'Style','text',...
               'Position',[20 200 210 140],...
               'HorizontalAlignment','left',...
               'String',ui_message(line1,line2,line3));

    uicontrol('Parent',d,...
               'Position',[85 20 70 25],...
               'String','Close',...
               'Callback','delete(gcf)');
end