Error in push button callback

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Aaron Smith
Aaron Smith 2017-3-31
评论： Rik 2019-7-27
I have created a GUI window with a push button. When pushed, a folder selection window should be generated and then when a folder is selected, the code of my callback should be executed. I have another window with a push button and a code that carries out a different but similar function which works perfectly fine. My question is effectively to get a second pair of eyes that might be able to spot the root of the error. The callback code:
% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject handle to pushbutton1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
myFile = uigetdir('C:\Users\c13459232\Documents\MATLAB'); % Generate command window to choose a folder
if ~isdir(myFile) % if the directory is not a valid path
errorMessage = sprintf('Error: the following file does not exist: \n%s', myFile); % print this error message
uiwait(warndlg(errorMessage)); % block the execution of program and wait to resume
return;
end
f2d = fopen(fullfile(myFile,'temp_01.asc'),'w'); % open a file to have data written into (fullfile builds full file name from parts)
f1d = fopen(fullfile(myFile,'TEST_A.asc'),'r'); % open the file to me looked at ('r' means read file)
k = 0;
while ~feof(f1d) % while find end of file, the TEST_A file
str = fgetl(f1d); %fgetl reads TEST_A line by line and this is identified by str
if sscanf(str,'%d')==1 % if the data (read line by line) from a string is equal to one
k = k+1; % k should increase by one with every block
fclose(f2d); % close the file that is being written to
fnm = fullfile(myFile,sprintf('temp_%02d.asc',k)); %build a full file from parts that are being formatted into strings
f2d = fopen(fnm,'w'); %open the parts to be written
end
fprintf(f2d,'%s\n',str); % writes the blocks to the file
end
fclose(f1d); %close the original TEST_A file
fclose(f2d); %close the new file
The error:
Undefined function 'just_push' for input arguments of type 'char'.
Error in @(hObject,eventdata)just_push('pushbutton1_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating uicontrol Callback
I can't see where the char input is being specified as this code worked previously, before i added it to the push button callback.

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回答（2 个）

Guillaume
Guillaume 2017-3-31
The part of the error you need to focus on is not the for input arguments of type 'char' . It is the undefined function 'just_push' part that is important.
Does that just_push callback function exist?
It's a bit unusual to have a callback function being given the name of another callback function as its first input argument, shouldn't that callback definition simply be:
@(hObject, eventdata) pushbutton1_Callback(hObject, eventdata, guidata(hObject))
or even simpler, since pushbutton1_Callback gets the hObject anyway it could query the guidata itself, and the callback definition could just be
@pushbutton1_Callback
with the definiton of pushbutton1_Callback:
function pushbutton1_Callback(hObject, eventdata)
% hObject handle to pushbutton1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
handles = guidata(hObject);
%... rest of the code
In any case, the error has nothing to do with the snippet of code you've posted.
  2 个评论
Aaron Smith
Aaron Smith 2017-3-31
function varargout = just_push(varargin)
% JUST_PUSH MATLAB code for just_push.fig
% JUST_PUSH, by itself, creates a new JUST_PUSH or raises the existing
% singleton*.
%
% H = JUST_PUSH returns the handle to a new JUST_PUSH or the handle to
% the existing singleton*.
%
% JUST_PUSH('CALLBACK',hObject,eventData,handles,...) calls the local
% function named CALLBACK in JUST_PUSH.M with the given input arguments.
%
% JUST_PUSH('Property','Value',...) creates a new JUST_PUSH or raises the
% existing singleton*. Starting from the left, property value pairs are
% applied to the GUI before just_push_OpeningFcn gets called. An
% unrecognized property name or invalid value makes property application
% stop. All inputs are passed to just_push_OpeningFcn via varargin.
%
% *See GUI Options on GUIDE's Tools menu. Choose "GUI allows only one
% instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES
% Edit the above text to modify the response to help just_push
% Last Modified by GUIDE v2.5 31-Mar-2017 11:55:28
% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name', mfilename, ...
'gui_Singleton', gui_Singleton, ...
'gui_OpeningFcn', @just_push_OpeningFcn, ...
'gui_OutputFcn', @just_push_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 just_push is made visible.
function just_push_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 just_push (see VARARGIN)
% Choose default command line output for just_push
handles.output = hObject;
% Update handles structure
guidata(hObject, handles);
% UIWAIT makes just_push wait for user response (see UIRESUME)
% uiwait(handles.figure1);
% --- Outputs from this function are returned to the command line.
function varargout = just_push_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 pushbutton1.
function pushbutton1_Callback(hObject, eventdata)
% hObject handle to pushbutton1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
handles = guidata(hObject);
myFile = uigetdir('C:\Users\c13459232\Documents\MATLAB'); % Generate command window to choose a folder
if ~isdir(myFile) % if the directory is not a valid path
errorMessage = sprintf('Error: the following file does not exist: \n%s', myFile); % print this error message
uiwait(warndlg(errorMessage)); % block the execution of program and wait to resume
return;
end
f2d = fopen(fullfile(myFile,'temp_01.asc'),'w'); % open a file to have data written into (fullfile builds full file name from parts)
f1d = fopen(fullfile(myFile,'TEST_A.asc'),'r'); % open the file to me looked at ('r' means read file)
k = 0;
while ~feof(f1d) % while find end of file, the TEST_A file
str = fgetl(f1d); %fgetl reads TEST_A line by line and this is identified by str
if sscanf(str,'%d')==1 % if the data (read line by line) from a string is equal to one
k = k+1; % k should increase by one with every block
fclose(f2d); % close the file that is being written to
fnm = fullfile(myFile,sprintf('temp_%02d.asc',k)); %build a full file from parts that are being formatted into strings
f2d = fopen(fnm,'w'); %open the parts to be written
end
fprintf(f2d,'%s\n',str); % writes the blocks to the file
end
fclose(f1d); %close the original TEST_A file
fclose(f2d); %close the new fileile
I replaced the code with what you suggested and got this error
Undefined function 'just_push' for input arguments of type 'char'.
Error in @(hObject,eventdata)just_push('pushbutton1_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating uicontrol Callback
I'm not sure why the naming of the window is causing problems for the callback
Aaron Smith
Aaron Smith 2017-3-31
I made a new window consisting of the same pushbutton and simply changed the name of the window from just_push to push_button and by adding my original callback, it works. I'm confused by how this could've caused a problem

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Beena Anand
Beena Anand 2019-7-27
is there is any addones to install for push button callback?
  1 个评论
Rik
Rik 2019-7-27
No, callback functions and uicontrol are part of native Matlab. Also, this is not an answer to this question. Please open your own question or write a comment instead.

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