Updating GUI handles when using callback - matlab

Question

I have a GUI made from GUIDE and I cannot figure out how to update a GUI handle when I call a callback in a callback. So for instance in the function which calls the function all I have is the following:
function start_ss_Callback(hObject, eventdata, handles)
% hObject handle to start_ss (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Hints: get(hObject,'String') returns contents of start_ss as text
% str2double(get(hObject,'String')) returns contents of start_ss as a double
start_hh_Callback(hObject, eventdata, handles)
and in start_hh_Callback I have the code given below but my handles.plot_holds doesn't update regardless of the fact that I have guidata(hObject, handles). Is this because I'm using it as a function? If I just go through the start_hh_Callback itself not through start_ss_Callback, it updates. However, if I use it within a callback like start_ss_Callback it does not update.
I hope my question is clear, let me know if you need clarification.
function start_hh_Callback(hObject, eventdata, handles)
% hObject handle to start_hh (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Hints: get(hObject,'String') returns contents of start_hh as text
% str2double(get(hObject,'String')) returns contents of start_hh as a double
axes(handles.axes1)
if isempty(handles.plot_holds)
cla
plot_button_Callback(hObject, eventdata, handles)
else
% in the event the time is changed after more than 1 plot is held then
% the additional plot times will be re evaluated for each parameter and
% the new indicies will take into affect.
myParams = get(handles.load_params_button,'string');
mystartDD = str2num(get(handles.start_dd,'string'));
mystartHH = str2num(get(handles.start_hh,'string'));
mystartMM = str2num(get(handles.start_mm,'string'));
mystartSS = str2num(get(handles.start_ss,'string'));
myendDD = str2num(get(handles.end_dd,'string'));
myendHH = str2num(get(handles.end_hh,'string'));
myendMM = str2num(get(handles.end_mm,'string'));
myendSS = str2num(get(handles.end_ss,'string'));
startFromStart = (mystartDD)*60*60*24 + (mystartHH-handles.startHour)*60*60 ...
+ (mystartMM-handles.startMinute)*60 + (mystartSS-handles.startSecond);
endFromStart = (myendDD)*60*60*24 + (myendHH-handles.startHour)*60*60 ...
+ (myendMM-handles.startMinute)*60 + (myendSS-handles.startSecond);
iStart = find(handles.load.dataGST.(handles.myParams{handles.plot_holds(1,1)}).(handles.myPackets{handles.plot_holds(1,1)}{handles.plot_holds(1,2)}).Time > (startFromStart+handles.startTimeOffset),1);
iEnd = find(handles.load.dataGST.(handles.myParams{handles.plot_holds(1,1)}).(handles.myPackets{handles.plot_holds(1,1)}{handles.plot_holds(1,2)}).Time > (endFromStart+handles.startTimeOffset),1);
if isempty(iEnd)
iEnd = length(handles.load.dataGST.(handles.myParams{handles.plot_holds(1,1)}).(handles.myPackets{handles.plot_holds(1,1)}{handles.plot_holds(1,2)}).Time);
end
cla
hold off
plot(handles.load.dataGST.(handles.myParams{handles.plot_holds(1,1)}).(handles.myPackets{handles.plot_holds(1,1)}{handles.plot_holds(1,2)}).Time(iStart:iEnd),...
handles.load.dataGST.(handles.myParams{handles.plot_holds(1,1)}).(handles.myPackets{handles.plot_holds(1,1)}{handles.plot_holds(1,2)}).Data(iStart:iEnd))
grid minor
box on
handles.plot_holds(1,3) = iStart;
handles.plot_holds(1,4) = iEnd;
if size(handles.plot_holds,1)>1
hold all
for ii = 2:size(handles.plot_holds)
iStart = find(handles.load.dataGST.(handles.myParams{handles.plot_holds(ii,1)}).(handles.myPackets{handles.plot_holds(ii,1)}{handles.plot_holds(ii,2)}).Time > (startFromStart+handles.startTimeOffset),1);
iEnd = find(handles.load.dataGST.(handles.myParams{handles.plot_holds(ii,1)}).(handles.myPackets{handles.plot_holds(ii,1)}{handles.plot_holds(ii,2)}).Time > (endFromStart+handles.startTimeOffset),1);
if isempty(iEnd)
iEnd = length(handles.load.dataGST.(handles.myParams{handles.plot_holds(ii,1)}).(handles.myPackets{handles.plot_holds(ii,1)}{handles.plot_holds(ii,2)}).Time);
end
plot(handles.load.dataGST.(handles.myParams{handles.plot_holds(ii,1)}).(handles.myPackets{handles.plot_holds(ii,1)}{handles.plot_holds(ii,2)}).Time(iStart:iEnd),...
handles.load.dataGST.(handles.myParams{handles.plot_holds(ii,1)}).(handles.myPackets{handles.plot_holds(ii,1)}{handles.plot_holds(ii,2)}).Data(iStart:iEnd))
handles.plot_holds(ii,3) = iStart;
handles.plot_holds(ii,4) = iEnd;
end
end
end
legend(handles.myLegends{1:length(handles.myLegends)})
guidata(hObject, handles);

Answer 1

You'll have to load the handles again, after any handles-modifying function:
% this modifies and writes the handles to the guidata
start_hh_Callback(hObject, eventdata, handles);
% now read back the updated value
handles = guidata(hObject);
Alternatively you could also make handles the return value of you callback.
Usually this will be ignored when it's really used as a callback and when used as a "normal" function it avoids the need to re-read from guidata.
Your code could then look like this:
handles = start_hh_Callback(hObject, eventdata, handles);
with your callback redefined to:
function [handles] = start_hh_Callback(hObject, eventdata, handles)
...
end