Timer stop function // findobj returns nothing

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Hi, I constructed a timer to run a countdown, at the beginning of the countdown I want to turn a UserData variable to 'on'. At the end of the countdown I want it back to 'off'. My actuall code looks like that:
t = timer('Period', 1, 'TasksToExecute', stop_in_sec, 'ExecutionMode', 'fixedRate', 'ObjectVisibility', 'off');
t.StartFcn = { @run_timer, handles.Countdown_edit, 'Countdown started:'};
t.StopFcn = { @run_timer, handles.Countdown_edit, 'Countdown stopped'};
t.TimerFcn = { @run_timer, handles.Countdown_edit, ''};
t.UserData = stop_in_sec;
start(t)
and the timer callback:
function run_timer(t,event,Countdown_edit, varargin)
switch event.Type
case 'StopFcn'
Schalter = get(findobj('Tag', 'LiveCam_Tool'), 'UserData');
Schalter.xyz = 'on';
set(Countdown_edit, 'str', '-----');
delete(t);
case 'StartFcn'
Schalter = get(findobj('Tag', 'LiveCam_Tool'), 'UserData');
Schalter.xyz = 'off';
case 'TimerFcn'
set(Countdown_edit, 'str', t.UserData);
t.UserData= t.UserData-1;
end
After placing breakpoints in StopFcn, StartFcn and TimerFcn the programm was running. If I just place them in one or two Fcn's the "get(findobj('Tag', 'LiveCam_Tool'), 'UserData');" in StopFcn returns nothing. (The same in the StartFcn is still working!) Who can help me?

回答(1 个)

Walter Roberson
Walter Roberson 2013-10-8
The object might have a hidden handle, or might have a handle visible in callbacks. Try replacing findobj() with findall()
  1 个评论
Adrian
Adrian 2013-10-8
It tells me: Invalid handles passed to findall.
And now its not even running with breakpoints.

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