How do i repaired this coding, keep getting these errors i using Matlab2015b...

function varargout = gui_attention(varargin)
% GUI_ATTENTION MATLAB code for gui_attention.fig
%      GUI_ATTENTION, by itself, creates a new GUI_ATTENTION or raises the existing
%      singleton*.
%
%      H = GUI_ATTENTION returns the handle to a new GUI_ATTENTION or the handle to
%      the existing singleton*.
%
%      GUI_ATTENTION('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in GUI_ATTENTION.M with the given input arguments.
%
%      GUI_ATTENTION('Property','Value',...) creates a new GUI_ATTENTION or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before gui_attention_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to gui_attention_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 gui_attention

% Last Modified by GUIDE v2.5 25-Nov-2017 15:51:34

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @gui_attention_OpeningFcn, ...
                   'gui_OutputFcn',  @gui_attention_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 gui_attention is made visible.
function gui_attention_OpeningFcn(hObject, ~, 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 gui_attention (see VARARGIN)

% Choose default command line output for gui_attention
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes gui_attention wait for user response (see UIRESUME)
% uiwait(handles.figure1);

% --- Outputs from this function are returned to the command line.
function varargout = gui_attention_OutputFcn(~, ~, 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 start.
function start_Callback(~, ~, 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)

      %Preallocate buffer
      data_att = zeros(1,256);

      %Comport Selection
      portnum1 = 7;
      %COM Port #
      comPortName1 = sprintf('\\\\.\\COM%d', portnum1);

      % Baud rate for use with TG_Connect() and TG_SetBaudrate().
      TG_BAUD_115200 = 115200;

      % Data format for use with TG_Connect() and TG_SetDataFormat().
      TG_STREAM_PACKETS = 0;
      % Data type that can be requested from TG_GetValue().

      TG_DATA_ATTENTION = 2;

      %load thinkgear dll
      loadlibrary('Thinkgear.dll');

      %To display in Command Window
      fprintf('Thinkgear.dll loaded\n');

      %get dll version
      dllVersion = calllib('Thinkgear', 'TG_GetDriverVersion');

      %To display in command window
      fprintf('ThinkGear DLL version: %d\n', dllVersion );

      % Get a connection ID handle to ThinkGear
      connectionId1 = calllib('Thinkgear', 'TG_GetNewConnectionId');
      if ( connectionId1 < 0 )
          error( sprintf( 'ERROR: TG_GetNewConnectionId() returned %d.\n', connectionId1 ) );
      end;

      % Attempt to connect the connection ID handle to serial port "COM3"
      errCode = calllib('Thinkgear', 'TG_Connect', connectionId1,comPortName1,TG_BAUD_115200,TG_STREAM_PACKETS );
      if ( errCode < 0 )
          error( sprintf( 'ERROR: TG_Connect() returned %d.\n', errCode ) );
      end

      fprintf( 'Connected. Reading Packets...\n' );

      i=0;
      j=0;

      %To display in Command Window

      disp('Reading Brainwaves');

      figure;
      while i < 20
          if (calllib('Thinkgear','TG_ReadPackets',connectionId1,1) == 1) %if a packet was read...
              if (calllib('Thinkgear','TG_GetValueStatus',connectionId1,TG_DATA_ATTENTION ) ~= 0)
                  j = j + 1;
                  i = i + 1;
                  %Read attention Valus from thinkgear packets
                  data_att(j) = calllib('Thinkgear','TG_GetValue',connectionId1,TG_DATA_ATTENTION );

                  str=data_att(j);
                  strl=num2str(str);
                  set(handles.editl,'String',strl);
                  %To display in Command Window
                  disp(data_att(j));
                  %Plot Graph
                  axes(handles.axesl);
                  plot(data_att);

                  title('Attention');
                  %Delay to display graph
                  pause(1);
              end
          end
      end

      %To display in Command Window
      disp('Loop Completed')
      %Release the comm port
      calllib('Thinkgear', 'TG_FreeConnection', connectionId1 );

function edit1_Callback(~, ~, ~)
% hObject    handle to edit1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of edit1 as text
%        str2double(get(hObject,'String')) returns contents of edit1 as a double

% --- Executes during object creation, after setting all properties.
function edit1_CreateFcn(hObject, ~, ~)
% hObject    handle to edit1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end

......................................................................

This error keep coming

Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)gui_attention('start_Callback',hObject,eventdata,guidata(hObject)) 
Error while evaluating UIControl Callback

[Walter Roberson]

Please post the entire error message, everything in red.

You have given us enough information to know which callback is executing, but you have not told us where the problem is occurring and you have not shown as any output that might have shown up before that that might give us a clue as to how far the program is getting.

[Mufa Yusof]

Thank you for your reply, here i attach the error message.

    gui_attention
    Thinkgear.dll loaded
    ThinkGear DLL version: 22
    Error using gui_attention>start_Callback (line 123)
    ERROR: TG_Connect() returned -2.

    Error in gui_mainfcn (line 95)
            feval(varargin{:});

    Error in gui_attention (line 42)
        gui_mainfcn(gui_State, varargin{:});

Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)gui_attention('start_Callback',hObject,eventdata,guidata(hObject)) 
Error while evaluating UIControl Callback

Answer 1

[Jan]

The error message looks clear:

TG_Connect() returned -2.

Check this in Matlab directly without GUI:

portnum1 = 7;
comPortName1 = sprintf('\\\\.\\COM%d', portnum1);
TG_BAUD_115200 = 115200;
TG_STREAM_PACKETS = 0;
TG_DATA_ATTENTION = 2;
loadlibrary('Thinkgear.dll')
dllVersion = calllib('Thinkgear', 'TG_GetDriverVersion')
connectionId1 = calllib('Thinkgear', 'TG_GetNewConnectionId');
if connectionId1 < 0
    error('ERROR: TG_GetNewConnectionId() returned %d.', connectionId1);
end
errCode = calllib('Thinkgear', 'TG_Connect', ...
              connectionId1, comPortName1, TG_BAUD_115200, TG_STREAM_PACKETS );
if errCode < 0
  error('ERROR: TG_Connect() returned %d.', errCode);
end

(I've simplified e.g. the error messaged.) Try to solve the problem in the command window at first. There is a reason, why your get an error code of -2. Look in the documentation, what this number means.

Answer 2

[Walter Roberson]

https://www.mathworks.com/matlabcentral/answers/277429-i-am-using-mindwave-mobile-have-problem-to-data-acquition-in-matlab#answer_216673