MatlabGUI中的timer为什么无法停止？

[校园恶狼]

原程序如下：
function start_Callback(hObject, eventdata, handles)
% hObject handle to start (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
guidata(handles);
timerID=timer('timerFcn',{@timerCallback},'ExecutionMode','fixedDelay','Period',10.0);
stoprun=get(hObject,'Value');
if stoprun
start(timerID);
else
alltimers = timerfind;
if length(alltimers)>0
stop(timerID);
delete(alltimers);
end
end
其中timerCallback为数据采集的程序，start按钮为toggle按钮。在程序运行时，点击start按钮无法响应。为什么？