I am creating an application in GUIDE. I've found that using the "handles" structure provided by GUIDE to store data quickly leads to messy/hard to read code. I decided that the best solution is to create my own class to handle data as well as store methods to be used in callback functions. I've been able to successfully call the constructor method in "annotatorGUI_OpeningFcn" (seen below), but when I call a class method in a different callback function, it can't find any reference to my class. Furthermore, the line "annotatorEngine = ...." is underlined in yellow with the statement "value assigned to variable might be unused". It seems that my class declaration doesn't propagate throughout the entire GUI script. I want to avoid using the "handles" structure or declaring "annotatorEngine" as global. Thanks!
EDIT: So far it seems the only thing that has worked is declaring my class object as global. However, this is still slightly annoying because in each callback, I have to write "global annotatorEngine".
% --- Executes just before annotatorGUI is made visible.
function annotatorGUI_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 annotatorGUI (see VARARGIN)
% Choose default command line output for annotatorGUI
handles.output = hObject;
% Update handles structure
guidata(hObject, handles);
% CLASS CONSTRUCTED HERE
annotatorEngine = annotatorGUIClass(handles.rawAxes, handles.psdAxes, handles.allPairsAxes)
% UIWAIT makes annotatorGUI wait for user response (see UIRESUME)
% uiwait(handles.figure1);
Place where I call a method.
% --------------------------------------------------------------------
function loadData_Callback(hObject, eventdata, handles)
% hObject handle to loadData (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
[FileName, PathName] = uigetfile('*.mat', 'Select a data file to load');
annotatorEngine.loadData(FileName, PathName)
return
Related
I want to make simple GUI for my script, where I can edit parameter values and running that script.
I've created example scipt and GUI with 2 buttons. I'cant put script code into GUI code, I will need to aply it on much larger script.
So, script code:
number = 10;
variable(1:10) = NaN;
for i = 1:10;
variable(i) = i * number;
end
figure
plot(variable)
Push button code, that is working fine. script is name of .m file, not function:
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)
evalin('base','script')
But I dont know what to type into edit button code If i want to change value of "number" in the script:
function edit1_Callback(hObject, eventdata, handles)
% 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
And last thing, sometimes when I try to plot more graphs, one figure overwrites GUI figure and I can see only buttons, but not whole GUI.
Thank you fot any help.
The hint given in the last piece of code is enough.
a = str2double(get(hObject,'String'));
This will save the input value as a double, in the callback function's stack.
In order to pass this value to the caller script's (base) stack, use assignin
assignin('base', 'number', a)
I have created a matlab gui and I want to use the variable magE from the function (pushbutton1) in the function (pushbutton2).
How can I call it?
magE = matrix of 244 rows and 2000 Columns
I would be grateful for any help. Thank you!
You should be using the hObject handle to pass data between GUI functions and callbacks, it's all quite well explained in the auto-generated comments. Example taken from MATLAB documentation:
% --- Executes just before simple_gui_tab is made visible.
function my_GUIDE_GUI_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 simple_gui_tab (see VARARGIN)
% ...
% add some additional data as a new field called numberOfErrors
handles.numberOfErrors = 0;
% Save the change you made to the structure guidata(hObject,handles)
Suppose you needed to access the numberOfErrors field in a push button callback. Your callback code now looks something like this:
% --- Executes on button press in pushbutton1.
function my_GUIDE_GUI_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)
% ...
% No need to call guidata to obtain a structure;
% it is provided by GUIDE via the handles argument
handles.numberOfErrors = handles.numberOfErrors + 1;
% save the changes to the structure
guidata(hObject,handles)
One way would be to declare magE as a global variable in the main script.
Then, inside each function you should also declare it as global so that it would refer to the same global variable.
e.g.
global magE
<your_code_here>
function [] = pushbutton1()
global magE
%%<your_code_here>
end
function [] = pushbutton2()
global magE
%%<your_code_here>
end
I am starting with MatLab.
I created a guide UI. I went ahead and assumed I could just add new feild to the handles structure created.
Can I do this?
For example, when I refer to handle.s in my program, I get an error that I am reffering to a non existing feild.
handles.s was created to store a serial port object generated in a function that initialises serial communication between my PC and a microcontroller.
the serial port object has methods and feild of its own...could it be that I cannot pass an object as a feild to the handles object that contains the property of the guide UI?
Here is the code I am working with
function [ s, flag] = setupSerial(comPort)
%Initialize serial port communication between Arduino and Matlab
%Ensure that the arduino is also communicating with Matlab at this time.
%if setup is complete then the value of setup is returned as 1 else 0.
flag =1;
s = serial(comPort);
set(s,'DataBits',8);
set(s,'StopBits',1);
set(s,'BaudRate',9600);
set(s,'Parity','none');
fopen(s);
a='b';
while (a~='a')
a=fread(s,1,'uchar');
end
if (a=='a')
disp('serial read');
end
fprintf(s,'%c','a');
mbox = msgbox('Serial Communication setup.'); uiwait(mbox);
fscanf(s,'%u');
end
Within my UserInterface.m file, I pass over the object in a claaback function as follows
function SerialBtn_Callback(hObject, eventdata, handles)
% hObject handle to SerialBtn (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA
comPort = get(handles.COMportTxt,'String');
if(~exist('serialFlag','var'))
[handles.s, handles.serialFlag] = setupSerial(comPort);
end
end
I get the error when I press the 'Home' button. Here is the callback funciton
function HomeButton_Callback(hObject, eventdata, handles)
% hObject handle to HomeButton (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
disp('home button pressed');
fprintf(handles.s,'%s', 'G2');
set(handles.CurrentPositionTxt, 'String', '0');
end
There error I get is the following
Reference to non-existent field 's'.
Here the GUI for you information
The callback where handles.s is defined is not saving the handles object. You must save it using guidata in order to have it available later in another callback.
function SerialBtn_Callback(hObject, eventdata, handles)
% hObject handle to SerialBtn (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA
comPort = get(handles.COMportTxt,'String');
if(~exist('serialFlag','var'))
[handles.s, handles.serialFlag] = setupSerial(comPort);
end
guidata(hObject,handles)
Hope this helps.
I'm kind of new to MATLAB and I'm doing some experiments for a school project.
What I want is a GUI with 3 buttons, when you press either of the first two, it adds up to one on a variable (one variable for each button), and when you press the third button, it does something with the variables from the first two buttons.
I used "guide" and dragged and dropped the buttons, and then I modified the functions.
But I realized that my variables only exist inside the function for the button, so if I initialize them they would restart everytime I press the button, and also there is no way for my third button to know the value of the first two.
Is there a way to make this variables always present? Or pass them from a function to another?
My code it's just the automatic code generated by "guide", with a v1 = v1+1; in the first button callback function and v2 = v2+1 in the second one, and disp(v1) disp(v2) in the third.
I hope you understand what I mean, I'm not a native english speaker so...
Anyway, thanks a lot, hope it's something easy to fix.
You have several options:
use global variables as nhowe suggested. But using global variables is not a good practice: see Top 10 MATLAB code practices that make me cry, or Wikipedia article
use setappdata / getappdata functions to store your variables (this is the simpler one)
learn how to use and properly update the handles structure that appears in each callback function for GUI controls created in GUIDE (this one is more complicated).
Here is an example of *.m file for case #3. Most of GUIDE-generated code was removed showing only things related to your variables. Basically, you have to update the handles structure in each callback function that does some changes to it with guidata(hObject, handles); line. After this all subsequent callbacks will see the updated handles structure.
function varargout = GUIProgramWithVariables(varargin)
% Here goes some comment from GUIDE
% Begin initialization code - DO NOT EDIT
% . . . actual code skipped
% End initialization code - DO NOT EDIT
% --- Executes just before GUIProgramWithVariables is made visible.
function GUIProgramWithVariables_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 GUIProgramWithVariables (see VARARGIN)
% Choose default command line output for GUIProgramWithVariables
handles.output = hObject;
% Here your code starts. It should be at the end of OpeningFcn
% Add your fields to handles structure
handles.C1 = 1;
handles.C2 = 2;
handles.C3 = 3;
% this updates modified handles structure
% so all subsequent call-backs will see the changes
guidata(hObject, handles);
% --- Executes on button press in Button1
function Button1_Callback(hObject, eventdata, handles)
% hObject handle to BrowseButton (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Here we do the magic with Button1
handles.C1 = handles.C1 + 1;
% this updates modified handles structure
% so all subsequent call-backs will see the changes
guidata(hObject, handles);
% --- Executes on button press in Button2
function Button1_Callback(hObject, eventdata, handles)
% hObject handle to BrowseButton (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Here we do the magic with Button2
handles.C2 = handles.C2 + 1;
% this updates modified handles structure
% so all subsequent call-backs will see the changes
guidata(hObject, handles);
% --- Executes on button press in Button3
function Button3_Callback(hObject, eventdata, handles)
% hObject handle to BrowseButton (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Here we do the magic with Button3
handles.C3 = handles.C1 + handles.C2;
% this updates modified handles structure
% so all subsequent call-backs will see the changes
guidata(hObject, handles);
The following is not the best practice for large complicated programs, but for something simple like what you're trying to do it sounds like global variables would be perfect. Say that X, Y, and Z are the variables you want to share between functions. Add the following at the beginning of every function that uses them, and they will all have access to the same values.
global X Y Z
I have created a simple GUI to preview webcam stream and to get snapshot from it. For this I have created on axes to show video, one push button(pushbutton1) to start preview, one push button(pushbutton2) to get snapshot. Following is the code for these two push buttons.
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)
axes(handles.axes1);
vidObj = videoinput('winvideo',1);
videoRes = get(vidObj, 'VideoResolution');
numberOfBands = get(vidObj, 'NumberOfBands');
handleToImage = image( zeros([videoRes(2), videoRes(1), numberOfBands], 'uint8') );
preview(vidObj, handleToImage);
% --- 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)
a=getsnapshot(get(axes,'Children'));
imshow(a);
In pushbutton2_Callback I am trying to get child of axes ie. vidObj. But this gives me error ??? Undefined function or method 'getsnapshot' for input arguments of type 'double'.. Why is it returing double type instead of child object vidObj?
How can I fix it and get snapshot?
Is there any other better way?
(I just started learning GUI.)
Thanks.
A better alternative to declaring your variables global, is to use the handles structure for sharing data. GUIDE already uses this structure to store handles to all GUI components. Simply add your data as a field to this structure that gets passed around to all callback functions.
So inside the first callback:
function pushbutton1_Callback(hObject, eventdata, handles)
%# ... your existing code ...
%# store video object in handles, and persist
handles.vidObj = vidObj;
guidata(hObject,handles)
end
Then in the second, you can retrieve the video object from the handles structure:
function pushbutton2_Callback(hObject, eventdata, handles)
frame = getsnapshot(handles.vidObj);
imshow(frame);
end