MATLAB programmatic GUI listbox value and data it refers to - matlab

Question

I am making a GUI programmatically and have run into a small question regarding the uicontrol listbox and the data each 'value' or 'string' refers to. I feel this question will best be illustrated with some code. The code at the end of this question illustrates my question.
If you run this example, select all 5 files from the left listbox and press 'Button1', you will see them go into the right listbox. You can then select 1, or several of the files in the right list box and press 'Button2' and MATLAB will output the correct files names. All is fine here.
If you close and re run the program, and just select file1, file3, and file5, pressing Button1 will make them go into the right list box again. This is where my problem is: If you select all of the files now in the right list box (file1, file3, file3), and press Button2, matlab outputs file1, file2, and file3... not file1, file3 and file5 as I would like.
Now I understand why this is happening, because in a list box its value property starts at 1 and increases, and the underlying data in the Cell DataSet remains ordered file1 to file5... So value 1 2 3 refers to DataSet{1} DataSet{2} DataSet{3}...
What would be the best way to overcome this problem? I would like to add that for my actual GUI the file names might not always be so obviously named.
classdef example < handle
properties
Figure;
Button1;
Button2;
ListBox1;
ListBox2;
DataSet = {};
end
methods
function obj = example()
create(obj);
makeUpData(obj);
end
function create(obj)
obj.Figure = figure('Position',[300 300 640 640]);
obj.Button1 = uicontrol('Style','pushbutton','String','Button1',...
'Position',[240 260 80 40],'Callback',#obj.button1CB);
obj.Button2 = uicontrol('Style','pushbutton','String','Button2',...
'Position',[510 260 80 40],'Callback',#obj.button2CB);
obj.ListBox1 = uicontrol('Style','listbox','String','',...
'Position',[50 250 145 100],'Max',3);
obj.ListBox2 = uicontrol('Style','listbox','String','',...
'Position',[350 250 145 100],'Max',3);
end
function makeUpData(obj)
obj.DataSet = {'file1' 'file2' 'file3' 'file4' 'file5'};
obj.ListBox1.String = obj.DataSet;
end
function button1CB(obj,hObject,eventdata)
CurrentNum = get(obj.ListBox1,'Value');
NameListBox1 = get(obj.ListBox1,'String');
NewName = obj.ListBox2.String;
for i = 1:numel(CurrentNum)
NewName{end+1} = [NameListBox1{CurrentNum(i)}];
end
obj.ListBox2.String = NewName;
end
function button2CB(obj,hObject,eventdata)
CurrentNum = get(obj.ListBox2,'Value')
for i = 1:numel(CurrentNum)
obj.DataSet{CurrentNum(i)}
end
end
end
end

Answer 1

For this application I would recommend storing your data in a structure rather than a cell array. This will allow you to utilize dynamic field references to access your data and not worry about converting from a file name to an index in your cell array.
I've modified your properties definition:
properties
Figure;
Button1;
Button2;
ListBox1;
ListBox2;
DataSet = struct;
end
Your makeUpData definition:
function makeUpData(obj)
dummydata = {'file1' 'file2' 'file3' 'file4' 'file5'};
for ii = 1:length(dummydata)
obj.DataSet.(dummydata{ii}) = dummydata{ii};
end
obj.ListBox1.String = fieldnames(obj.DataSet);
end
And your button2CB definition:
function button2CB(obj,hObject,eventdata)
listboxvalues = get(obj.ListBox2, 'String');
CurrentNum = get(obj.ListBox2,'Value');
for i = 1:numel(CurrentNum)
obj.DataSet.(listboxvalues{CurrentNum(i)})
end
end
Now your selection returns:
ans =
file1
ans =
file3
ans =
file5
As expected.

Answer 2

You can change callback function of Button2 as follows, using ismember to get the corresponded index in the obj.DataSet:
function button2CB(obj,hObject,eventdata)
selected = cellstr(get(obj.ListBox2, 'String'));
referred = ismember(obj.DataSet, selected);
obj.DataSet(referred)
obj.DataSet{referred}
end