How to Create RT clock in my own GUI?
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Hello,
I have the following code (it's upon GUI creation):
set(handles.time_caption,'String',datestr(now,13))
tmr = timer('Name','Reminder', ...
'Period',1, ... % Update the time every 1 seconds.
'StartDelay',0, ... % In seconds.
'TasksToExecute',inf, ... % number of times to update
'ExecutionMode','fixedSpacing', ...
'TimerFcn',{@updater_mg});
start(tmr); % Start the timer object.
function [] = updater_mg(varargin)
set(handles.time_caption , 'string' , datestr(now,13))
end
I receive the following error:
Error while evaluating TimerFcn for timer 'Reminder'
Undefined variable "handles" or class "handles.time_caption".
I understand that when I'm "inside" the updater_mg function it doesn't recognize my handles struct from a layer above.
How can I overcome this?
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Jan
2017년 6월 26일
편집: Jan
2017년 6월 26일
If handles is unknown in the callback, provide it as input:
set(handles.time_caption,'String',datestr(now,13))
tmr = timer('Name','Reminder', ...
'Period',1, ... % Update the time every 1 seconds.
'StartDelay',0, ... % In seconds.
'TasksToExecute',inf, ... % number of times to update
'ExecutionMode','fixedSpacing', ...
'TimerFcn',{@updater_mg, handles}); % <== HERE
function updater_mg(TimerH, EventData, handles) % <== AND HERE
set(handles.time_caption , 'string' , datestr(now,13));
end
Add a security check:
function updater_mg(TimerH, EventData, handles) % <== AND HERE
if ishandle(handles.time_caption)
set(handles.time_caption , 'string' , datestr(now,13));
else
disp('Timer for clock stopped: GUI was closed');
stop(TimerH);
end
end
댓글 수: 4
Jan
2017년 6월 27일
Search in the documentation of Matlab for the term "callback":
docsearch callback
There you find the description, that all callbacks get two default inputs: The handle of the affected object and a description of the event. Therefore definining the callback with 1 output means, that it is called with 3 inputs. For 'TimerFcn', @updater_mg the callback would get 2 inputs.
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