I'm currently learning MATLAB's GUIDE gui programming. I notice that when I place some objects in a figure, a corresponding 'CreateFcn' callback function is creating in the associated .m file. MATLAB's comments state that this function is executed when the object is created (I would consider this a constructor for the object).
However, I've noticed that not all objects seem to have this 'CreateFcn' constructor. Static text objects do not appear to have this callback function. And as of currently, it seems like this function just makes the code more difficult to read. Thus I'm curious if I can delete.
By deleting it, I tend to get an error in my code stating that the function can't be found. So my question: is it possible to delete the 'CreateFcn' method to declutter my code?
Thanks,
Surely it is possible.
Double-click the object to open up the inspector window, locate the "CreateFcn" property and set its value to an empty string. Then go to the .m file and remove the code of CreateFcn. This way MATLAB wouldn't complain about the missing CreateFcn anymore.
CreateFcn is not really a constructor per se, since it happens after all properties of the object are already set. It is more like an optional post-constructor event that gives user an opportunity to further customize the object's initial behavior dynamically. For example, you can customize the object's color at creation depending on the background color on which the object appears. For most control objects, the default behavior is probably already good enough for you. So you can safely remove those CreateFcns until you find a good excuse to use one.
1) Goto the View --> Property Inspector
2) expand the Creation and deletion control, remove the text from CreateFcn and DeleteFcn 3) close the property inspector save the respective GUI (Don't forget to save)
4) remove the callbacks in m-script.
Related
If for example you have acquired a object of type handleplot with expression like below:
handle = plot(t,functoin1 , t , function2 ) ;
Now handle will be an array that contains two elements, handle(1) and handle(2). Now suppose you want to change some properties of one of these objects, like set a LineWidth, change the Color, or the like.
Is there any way in which you can activate auto-completion or suggestions when you type handle(1). (note the memebership operator .)? I am looking for the automatic suggestions that MATLAB provides for member functions in a combobox near the blinking cursor, similar to the way other IDEs provide this feature:
MATLAB's objects support tab completion. After typing handle(1). simply hit tab and you will receive a list of available methods and properties of the graphics object.
If you want more help on a method, you will also get a popup dialog of the method and the accepted input arguments.
If you want to programmatically get a list of properties of an object, you can use properties
properties(t)
If you want a listing of all properties and their values, just use get
get(t)
i use this method ...
for example i'm writing a program in matlab editor and when im want to know the properties of an object just stop coding and run the program , know it's have my object (for example handle) and know i can write the properties(handle) in command window to know the exact properties of handle . as Suever says .
I have tried all possible means to figure out the return type of imshowpair command in MATLAB but I still was not able to find its return type.
I would be very thankful if someone could tell me its return type.
In the future, using class is a very easy way to determine the type of a variable that is returned by a function.
According to the documentation, the output of imshowpair is simply the graphics handle to the image object that is created.
h = imshowpair(rand(10), rand(10));
class(h)
matlab.graphics.primitive.Image
You can use this graphics handle to change the appearance of the displayed image. You can call get(h) to get a list of all properties you can get/set and their current values. The documentation for the image object provides a complete list along with the description of each of these properties.
There are three major ways to do so:
Thanks to the help. By browsing the help page for imshowpair(), which can be found here, you can click on the output h and the hyperlink will show you some infos about it which, in this case, is:
handle to Handle Graphics image object.
Image object, returned as a
handle to the Handle Graphics image object created by imshowpair.
Thanks to the Workspace. In Matlab you can setup your window layout in order to show the Workspace that is a list of all the Matlab variables you have in memory. In the Workspace you can as well show the class (type). In this case you'll see something like (excuse my tiny Workspace window):
Thanks to the class() function. I have C as output from imshowpair() and by typing class(C) I get:
matlab.graphics.primitive.Image
which is the same result as in the Workspace case.
I'm currently designing a GUI to open a MAT file(s) to store the time-series variables in it as properties in a class, and do things to the data within the class. The Class is pretty well defined, however, it is the I/O portion of it that I need guidance on.
The constructor of the class currently is written to set the properties to empty if there are no inputs. However, I have a method that has a UIOPEN to get the file and set the properties of the class.
I have created a GUIDE GUI, where I pass the empty object of the class to the handles of the GUI and store it using guidata. The GUI has a button (along with other elements) called "Get File" that will call the property setter method when clicked to populate the properties and a listbox with those properties.
The uncertainty is in the whole architecture of what I have done. I'd like to know if there is a better way to accomplish this. It seems like it's kind of a mickey mouse way of doing it. Thanks!
I can point out a few things:
GUIDE is old, weird and it is generally better to create GUIs programmatically
once you have gotten rid of GUIDE you can have the object govern the GUI behavior easily - the object could have methods to spawn and refresh the gui, hold handles to gui elements in private properties etc.
Creating object-manged guis can also save you some problems with syncing workspace with the gui without using global, assignin or evalin. Since the object holds the data and it also governs the gui - the problem is no longer present.
Mathworks disencourages using guidata for things other than handles to graphical objects, and advices the user to use appdata
How can one capture keyboard entry inside a uipanel, i.e. when anything in the panel has focus? I've found that uipanel does not have the KeyPressFcn property. I've read this post from Undocumented Matlab about Java callbacks, but I also can't get KeyPressedCallback to work. For example, if I try to this:
set(h_panel, 'KeyPressFcn', #(src, event)key_press(obj, src, event));
I get this error:
The name 'KeyPressFcn' is not an accessible property for an instance of class 'uicontrol'.
The same thing occurs if I try KeyPressedCallback. I'm afraid I'll have to resort to some sort of hack involving the parent figure, which I would like to avoid if possible.
KeyPressedCallback is a property of the underlying Java object, not the original Matlab uicontrol object. To access the underlying Java control of a Matlab uicontrol, you need to use the findjobj utility, as I believe that I explained in my blog post that you referenced (you probably missed that crucial step):
jPanel = findjobj(hPanel);
jPanel.KeyPressedCallback = #myMatlabCallbackFunc;
Note that Matlab panels only became Java-based objects in HG2 (R2014b, see here). So on R2014a and earlier Matlab releases you will not be able to use this technique, only on one of the newer releases.
I don't see any callback properties that you can use or events to which you can attach a listener.
>> events(h_panel)
Events for class matlab.ui.container.Panel:
ObjectBeingDestroyed
LocationChanged
SizeChanged
ButtonDown
Reset
PropertyAdded
PropertyRemoved
Just the mouse event (ButtonDown) and the ButtonDownFcn callback. Perhaps there are other tricks. Ask Yair Altman!
Ultimately, I have found there are two reasonable solutions to this problem, both involving what I originally described as "some sort of hack involving the parent figure". Both of them require some sort of concept of an "active" panel or object within the figure in question.
Solution 1
Rely on the last-clicked object to direct keyboard input in the figure to that object. Use ButtonDownFcn for every object in the figure that needs keyboard input. In the callback, store the handle of the object in the appdata of the figure as the "active" object. (Something like setappdata(h_fig, 'active_obj', h_obj.) Then set KeyPressFcn in the figure to a function that will get that handle out of the appdata and branch accordingly.
Solution 2
Use some sort of keypress scheme to decide which object to direct further input to. This works well if you have a number of similar objects that merely need disambiguation. For example, set the KeyPressFcn of the figure to a function that uses keys 1-9 to indicate the correspondingly numbered object. Direct further keyboard input to that object or a related function.
Neither method is perfect, and I wish there was a way to avoid going through the figure, but in practice these aren't very complicated to implement. I'm actually using both simultaneously.
Say, I have two following files:
A.m with matlab code that contains function callbacks and
A.fig with corresponding user interface file.
Now, I'm making copy of these two files:
A_copy.m
A_copy.fig
These two files were created by just copying the first ones. Now the questions is, why debugger does not stop inside callbacks? Inside other function debugger stops in its normal way, but not in callbacks. Of course, I've changed function name in A_copy.m from A to A_copy.
Which problem may I face?
Thanks.
Oh my God.
To fix this problem I had to go to main window editor properties and change NAME property. Just a string that contains title of the gui window. Why? Why? Why, Mathworks, WHY?
I can't believe it is made in so stupid way!