Running handles from GUI using timer object

Question

Lem 2011-10-12

2
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/18070-running-handles-from-gui-using-timer-object

Hello,

I am a beginner to MATLAB, tried searching on the help docs and Google, but wasn't able to figure out why my timer object won't run a particular GUI handle. I generated the GUI using GUIDE. The problem I have, in brief is following: I can call my function 'rando' from a button callback, but it doesn't seem to work if I call it from a timer object.

If you could please help me with this, I'd appreciate it. Thanks in advance. Here's the code:

    function varargout = trial(varargin)
% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @trial_OpeningFcn, ...
                   'gui_OutputFcn',  @trial_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end
if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT
% --- Executes just before trial is made visible.
function trial_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to trial (see VARARGIN)
% Choose default command line output for trial
handles.output = hObject;
% [X, map] = imread('C:\Users\Lemonickous\Documents\Courses\DC\DCseminar\images, etc\dc\untitled.jpg');
% image(X)
% colormap(map)
% axis off
handles.a = timer;
% Update handles structure
guidata(hObject, handles);
% UIWAIT makes trial wait for user response (see UIRESUME)
% uiwait(handles.figure1);
% --- Outputs from this function are returned to the command line.
function varargout = trial_OutputFcn(hObject, eventdata, handles) 
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% Get default command line output from handles structure
varargout{1} = handles.output;
% --- Executes on button press in pushbutton2.
function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
%trial2;
delete(handles.figure1);
% --- Executes on button press in generate.
function generate_Callback(hObject, eventdata, handles)
% hObject    handle to generate (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
t2 = randi(10);
set(handles.a, 'ExecutionMode', 'fixedrate');
set(handles.a, 'Period', .1);
set(handles.a, 'TasksToExecute', t2);
set(handles.a, 'TimerFcn', 'rando(hObject, eventdata, handles)');
start(handles.a)
% --- Executes on button press in button2.
function button2_Callback(hObject, eventdata, handles)
% hObject    handle to button2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
rando(hObject, eventdata, handles);
function rando(hObject, eventdata, handles)
t = randi(3);
if t == 1
    out = 200000;
elseif t == 2
    out = 240000;
else
    out = 280000;
end
set(handles.disp, 'String', num2str(out));

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2011-10-12

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/18070-running-handles-from-gui-using-timer-object#answer_24336

在 MATLAB Online 中打开

Any callback coded as a string is executed within the context of the base workspace. The base workspace does not have a rando function defined in it, as rando is private to the file trial.m

You should instead pass a function handle.

Do it like this:

function generate_Callback(hObject, eventdata, handles)
% hObject    handle to generate (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
t2 = randi(10);
set(handles.a, 'ExecutionMode', 'fixedrate');
set(handles.a, 'Period', .1);
set(handles.a, 'TasksToExecute', t2);
set(handles.a, 'TimerFcn', {@rando, hObject});
start(handles.a)
% --- Executes on button press in button2.
function button2_Callback(hObject, eventdata, handles)
% hObject    handle to button2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
rando(hObject);
function rando(hObject)
t = randi(3);
if t == 1
    out = 200000;
elseif t == 2
    out = 240000;
else
    out = 280000;
end
handles = guidata(hObject);
set(handles.disp, 'String', num2str(out));

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Lem 2011-10-12

Thanks a lot Walter, it worked!

请先登录，再进行评论。

Answer 2

Jeff D. 2011-12-7

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/18070-running-handles-from-gui-using-timer-object#answer_30642

I'm trying to do something similar. This isn't an answer, but a question about your code and GUI. Are pushbutton2, generate, and button2 all different push buttons? What is the rando() function for? I'm trying to use a variable from a different m-file (presently trying it as a global) but don't understand how to tie it to the timer function, i.e. I want to update the GUI periodically without pressing a button.

7 个评论
显示 5更早的评论隐藏 5更早的评论

Walter Roberson 2011-12-7

Yes, all three of those are different push buttons.

randio is there as a helper function to generate a random value that is either 200000 or 240000 or 280000 .

randio could have had its logic coded differently; it could have been coded as

function rando(hObject)

out = 200000 + randi(3) * 400000;

handles = guidata(hObject);

set(handles.disp, 'String', num2str(out));

But that's not really important. It is just some work that needs to be done when "button2" is pressed or the timer goes off, that the user choose to encapsulate in to a function.

Jeff, often the way to transfer data is to use

handles.YourVariable = NewValue;

guidata(handles);

and then the callback in the timer could use something like

function timer_updateGUI(hObject)

handles = guidata(hObject);

CurrentValue = handles.YourVariable

set(handles.Gui_Item, 'string', num2str(Currentvalue));

Of course the routine that set the value could have updated the GUI directly, but sometimes you want that setting routine to "run free" and update the internal data structures and then when the timer goes off, update the GUI with whatever the newest version of the data is.

You would, for example, use this kind of system for updating charts or plots with real-time data, which might involve a variable number of fetches from the instrument, but with graph updates to happen (say) every 3 seconds.

Walter Roberson 2011-12-7

Assuming you are not using nested functions to share variables:

The second routine needs to be able to access the GUI objects. To do that you could pass the handles of specific GUI objects to it (use a structure if there are more than one); or you could pass the handle of any object in the GUI to the second routine (the figure number if it is handy, but anything in the same figure if that is handier); or you could code a routine in the first section of code that will return either of those on demand; or you could use handle object Tag fields to tag something in the GUI and then use findobj() in the second GUI to search for that tag.

Once you have the handle of anything in the first GUI, you can use guidata() against that handle to return the current versions of the handles structure. You can access the fields of that structure and set() those handles to whatever value you want.

This probably sounds complicated, but that is mostly because of the flexibility. The code in your second routine could be as simple as

results_handle = findobj(0,'type','text', 'tag', 'results');

set(results_handle, 'String', 'Maximum bearing capacity exceeded. Limit one partridge per tree')

Jeff D. 2011-12-7

I was actually doing it the other way round, i.e. calling the GUI from the other routine, but could probably change and call my main file from the gui.

Walter Roberson 2011-12-7

The order doesn't really matter. When you call the GUI it will probably create the figures and uicontrols and set up their callbacks -- and then, having done those, return control to the calling routine. The figure number of the GUI is often returned as part of that.

The only important bit about the order is the "obvious in retrospect": the handle you wish to update in the GUI must have been created before you try to update it.

请先登录，再进行评论。

Running handles from GUI using timer object

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

更多回答（1 个）

7 个评论
显示 5更早的评论隐藏 5更早的评论

另请参阅

类别

标签

Community Treasure Hunt

Running handles from GUI using timer object

0 个评论 显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

1 个评论 显示 -1更早的评论隐藏 -1更早的评论

更多回答（1 个）

7 个评论 显示 5更早的评论隐藏 5更早的评论

另请参阅

类别

标签

Community Treasure Hunt

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

7 个评论
显示 5更早的评论隐藏 5更早的评论