Update pushbutton string using counter when another pushbutton is active - matlab

Question

I am setting the handles in the opening function:
function Select_A_B_OpeningFcn(hObject, eventdata, handles, varargin)
handles.output = hObject;
handles.string = '';
new_count = 1;
set(handles.counter,'String',num2str(new_count));
if isempty(varargin)
varargin{1} = 1;
varargin{2} = 1;
end
A = {'Apple';'Orange';'Bag';'Cowboy'};
handles.pushbutton1text = A;
new_count = str2double(handles.counter.String);
handles.pushbutton1 = handles.pushbutton1text(new_count);
guidata(hObject, handles);
Then I am trying to change the handles to pushbutton1 when the pushbutton tagged as 'Next' is pushed:
function next_Callback(hObject, eventdata, handles)
current_count = str2double(get(handles.counter, 'String'));
new_count = current_count+1;
set(handles.counter,'String',new_count);
set(handles.pushbutton1,'String',get(handles.counter,'string');
guidata(hObject, handles);
I get the following error when I try to set the handles to pushbutton1:
Error using set
Conversion to double from cell is not possible.
I have tried several ways to fix the error, but no success yet. What am I doing wrong?

Answer 1

Here is a programmatic GUI which does what you want and is, in my opinion, much simpler to understand/debug. You can easily implement this using GUIDE; everything that comes before the pushbutton's callback can be put into the GUI Opening_Fcn.
I added comments in the code; if something is unclear please tell me.
function DisplayFruits
clear
clc
hFig = figure('Position',[200 200 300 300]);
handles.A = {'Apple';'Orange';'Bag';'Cowboy'};
handles.counter = 1;
%// Counter text
handles.CounterTitle = uicontrol('Style','text','Position',[50 200 60 20],'String','Counter');
handles.CounterBox = uicontrol('Style','text','Position',[130 200 60 20],'String','1');
%// Content of A
handles.TextTitle = uicontrol('Style','text','Position',[50 170 60 20],'String','Content');
handles.TextBox = uicontrol('Style','text','Position',[130 170 60 20],'String',handles.A{handles.counter});
%// Pushbutton to increment counter/content
handles.PushButton = uicontrol('Style','push','Position',[130 100 80 40],'String','Update counter','Callback',#(s,e) UpdateCallback);
guidata(hFig,handles);
%// Pushbutton callback
function UpdateCallback
%// Update counter
handles.counter = handles.counter + 1;
%// If maximum value possible, set back to 1.
if handles.counter == numel(handles.A)+1;
handles.counter = 1;
end
%// Update text boxes
set(handles.CounterBox,'String',num2str(handles.counter));
set(handles.TextBox,'String',handles.A{handles.counter});
guidata(hFig,handles);
end
end
Sample screenshot of the GUI:
As the user presses the button, the counter is incremented and the "content box" is updated.
Hope this helps!
As a side note, I think the error you got above was due to this command:
handles.pushbutton1 = handles.pushbutton1text(new_count);
here you assigned a string to the pushbutton but later you try to modify its String property and Matlab does not like it.