TimerFcn within GUI function to another GUI function

I am attempting to call one gui function from a gui function in a gui script so that I can pass various handles around.

Essentially how the program works is: Checkbox to stream data.

    function Checkbox_Callback(hObjects,eventdata,handles)
    onoff = get(hObject,'Value');
    if onoff == 1
       a = timer;
       set(a,'executionMode','fixedRate','Period',1,'TimerFcn','Stream');
       start(a)
    elseif onoff == 0
       stop(a)
    end

The next function is used to call the data from an external program. The function definitely works, it's just the issue of how to call it correctly from the set(a,'TimerFcn',XXXXXXXXX);

The "Stream" function is along these lines:

function Stream(hObject,eventdata,handles)
XPNetConnect();
out = XPNetRecv();
variable1 = out.Variable1;
... etc
%Calculations
handles.Value = something;
guidata(hObject, handles);
Run_Another_Callback(hObject, eventdata, handles)

Hopefully you get the gist of what I'm trying to do.

I would really appreciate the help.

Thank you in advance.

Answer 1

[Daniel Shub]

I would do things a little differently ...

Make your timer object when you make your gui. If you do it at this point, all the handles that Stream needs are known.

You could do:

handles.htimer = timer('executionMode', 'fixedRate', 'Period', 1, 'TimerFcn', @(h, evt)Stream(h, evt, handles));

Note the specification of TimerFcn as

@(h, evt)Stream(h, evt, handles)

You would then rewrite Checkbox_Callback to be

    function Checkbox_Callback(hObject,eventdata,handles)
    if get(hObject,'Value')
       start(handles.htimer)
    else
       stop(handles.htimer)
    end

[John]

One thing though is... how do I stop the timer?

I get the following ever time I uncheck the box:

Reference to non-existent field 'htimer'.

Error in ROSv2>Stream_Data_Callback (line 975)

stop(handles.htimer)

Error in gui_mainfcn (line 96)

feval(varargin{:});

Error in ROSv2 (line 42)

gui_mainfcn(gui_State, varargin{:});

Error in

@(hObject,eventdata)ROSv2('Stream_Data_Callback',hObject,eventdata,guidata(hObject))

Error while evaluating uicontrol Callback

...and the timer continues to run.

Answer 2

[Sean de Wolski]

use setappdata/getappdata for the required handles and timerfind to find the appropriate timers.

[John]

Thanks for the tips again. I'll try later and post back when working.

Cheers

Answer 3

[John]

Hi,

Thank you for your input. What are the meanings of 'h' and 'evt'?

I rewrote what you put as the following:

 function ROSv2_OpeningFcn(hObject, eventdata, handles, varargin)
 handles.htimer = timer('executionMode','fixedRate','Period',1,'TimerFcn',@(hObject,eventdata)Stream1(hObject,eventdata,handles));

then

function Stream_Data_Callback(hObject,eventdata,handles)
onoff = get(hObject,'Value');
if onoff == 1
 start(handles.htimer)
else
 stop(handles.htimer)
end
guidata(hObject, handles);

and

function Stream1(hObject, eventdata, handles)
...
...
...
...

But I get an error saying:

Error while evaluating TimerFcn for timer 'timer-1' 

H must be the handle to a figure or figure descendent.

Not sure how to go about fixing this, I previously used the exact properties of the suggested code, i.e. I used the

       @(h,evt)Stream1(h,evt,handles)

but got an error:

Error while evaluating TimerFcn for timer 'timer-1'
Undefined function or variable 'hObject'

as I call it in the function Stream1...

Thanks in advance again.

[John]

Hi!

Got it to work, I passed the additional variables to the functions (hObject and eventdata).

Thank you for your help.

[Nope]

What do you mean by that? I'm having the exact same problem and can't find a solution. What do you mean pass the additional variables, by the looks of the code you're passing all 3 variables already? Please help.

[Cait]

Yes, I am also experiencing the same problem. I get the "H must be the handle to a figure or figure descendent."

And then "Reference to non-existent field 'gotimer'", which is what I'm calling my timer the next time I call it.

What did you do?