This is quite elegant. Unfortunately, there is a problem with Matlab hanging (matlab 2018b, windows 8.1) in the searchComboUpdated(obj, jCombo, eventData, hPanel) function. The hang occurs at jSearchTextField.setText(selectedItem). From other articles on your blog I learned that it could be EDT related and I hence added the drawnow; pause(0.1); that sometimes solves this. In this case it doesn’t help. In a newly started Matlab I get a hang everytime. It doesn’t hang in debug mode, but as soon as I run it without a breakpoint, it hangs. So frustrating.. and so unfortunate that Matlab has all these issues. I tried longer pause-times as well..didn’t help. Do you have any ideas?

Best,
Peter

PS: the code:

function searchComboUpdated(obj, jCombo, eventData, hPanel)
    ptime = 0.1;
    selectedItem = regexprep(char(jCombo.getSelectedItem),']*>','');  % strip away HTML tags
    fprintf('1');
 
    jSearchTextField = hPanel.UserData(2).getComponent(0);
    fprintf('2');
    drawnow; pause(ptime);
 
    str = java.lang.String(selectedItem);
    drawnow; pause(ptime);
    fprintf('2b');
    drawnow; pause(ptime);
 
    jSearchTextField.setText(str);
    drawnow; pause(ptime);
    fprintf('3');
    drawnow; pause(ptime);
 
    jSearchTextField.repaint; drawnow; pause(0.01);
    fprintf('4');
 
    jAssetChooser = getappdata(hPanel,'jAssetChooser');
    fprintf('5');
 
    obj.updateSearch([],[],jCombo,jAssetChooser);
    fprintf('6');
end  % searchComboUpdated

I am iteressted in the same point. I can implemement

set(handle(jPanelObj,'callbackproperties'), 'ActionPerformedCallback', @myMatlabCallbackFunc);

and this works fine, but with this callback I can not trigger on return or enter.

Do anybody have an idea to this topic.

Best Regards Stev

I have now added some extra code and explanations to the main text, which should be more than enough for most Matlab developers. If it’s still not enough for you, then consider asking a professional Matlab developer to assist you.

Thanks.

I am trying to implement something very similar in a GUI I am making but after creating the Combo Box and running your above code, I am getting an error at the line:

assetClassIdx = getappdata(handles.cbAssetClass, 'assetClassIdx');

because there is no variable “handles.” What does this variable need to be?

Im having a problem with getting a keypress callback on R2015b for the simpe autocompletewidget:

strs = {'This','is','test1','test2'};
strList = java.util.ArrayList;
for idx = 1 : length(strs),  strList.add(strs{idx});  end
jPanelObj = com.mathworks.widgets.AutoCompletionList(strList,'');
javacomponent(jPanelObj.getComponent, [10,10,200,100], gcf);
set(handle(jPanelObj.getComponent,'callbackproperties'), 'KeyTypedCallback', @myMatlabCallbackFunc);

I would like to have this callback to register a ‘enter’ keystroke signifying a completed selection.

Any help would be greatly appreciated!

I’m trying to implement your Autocomplete widget in my GUI (more simple than yours).
I’ve decided to split the code to better understand it, but i have two problems:

1) I can’t select the word from the combobox dropdown panel or by typing in the search text-box

How can i do that? How can i get the selected word to use it?
I’ve tried with jAssetChooser.getSearchText or jCombo.getSelectedItem but it didn’t work.
Must i use the setappdata comand?

2) If the word doesn’t match with my the list i get this Java error:

Error using provaaa/updateSearch (line 94)
Java exception occurred:
java.lang.NullPointerException
	at javax.swing.DefaultComboBoxModel.(Unknown Source)

I’m using matlab 2016a.

This is my example code:
[*** very large code section removed ***]

Thanks in advance.
Stefano

I tried to go through your code but it seems I missed something. The variables hPanel and jCombo could not be found. Is there some code I missed?

In the 2 code rows you provided, the first command created the Java component jPanelObj, and the second command placed this component in the GUI figure using the javacomponent function.

If you wish to learn more about creating advanced Matlab GUIs and/or working with Java in Matlab, get my Matlab-Java book. If you have a commercial need, consider hiring me for a consulting project.

I’m trying to implement simple Auto Completion box in my simplistic GUI. And I have few Questions as a newbie to this area. I hope you would be patient enough to help me.

1. Can I implement these objects in my GUIDE built GUI? I started with GUIDE since it’s very easy to start going with. But I found that I don’t have this component. So How I get along?
2. As a follow-up to the last question, should I try to program my GUI from scratch? what are the advantages compared to the workload of creating everything manually?
3. Can you explain what each of the following commands in your example mean? I read your javacomponent article but I don’t understand how each argument affects the output.

jPanelObj = com.mathworks.widgets.AutoCompletionList(strList,'');
javacomponent(jPanelObj.getComponent, [10,10,200,100], gcf);

4. While playing around I tried to update the list. Updating the array was easy but I couldn’t find the object / property to update nor any proper update function to use. I tried different get options but it didn’t get me far enough.

Thanks,
Rami

However,
I still encounter the Java OutOfMemory Error.
My MATLAB Java Heap Memory is 384 MB (Default).

What my Java script doing here is reading the description from the database and display the description on the GUI.
When user press and release the down arrow on the keyboard, selection will be moved to next item and description will be updated.
The challenge is, when user holding the down arrow, selection will be moved to next item very quickly, but the description update speed can’t catch up with the selection move speed.
I am using the following statement to capture the memory usage.

free = java.lang.Runtime.getRuntime.freeMemory
total = java.lang.Runtime.getRuntime.totalMemory
max = java.lang.Runtime.getRuntime.maxMemory

I can see the Java is consuming a ton of memory.
Do you have any thought on releasing the Java memory or only way we can do is increasing the heap size?

Thanks a lot.

So I am looking for another solution to approach my goal.
I try to reproduce your code on my machine. But I have question on the following statement.

assetClassIdx = getappdata(handles.cbAssetClass, 'assetClassIdx');

What is “handles” here for? jCombo? jAssetChooser? Or something else?

You can upgrade Java by copying the Java 8 JRE to your MATLAB app folder with many fewer problems than occurred with Java 6 -> Java 7.

To enable JavaFX, add javafxrt.jar (from the JRE) to your Java path using javaaddpath, then create an instance of javafx.embed.swing.JFXPanel. This will cause the JRE to do the work for you and initialise the JavaFX application thread.

If you create a JavaFX application, be sure to prevent javafx.application.Platform.exit() being called when you close it. The JavaFX thread will not robustly initialise twice in a given MATLAB instance. See https://docs.oracle.com/javase/8/javafx/api/javafx/application/Platform.html

There are threading issues between the the AWT/Swing EDT and the JavaFX application thread but I understand that these have been reduced for contents of a JFXPanel in the latest Java 8 releases. JFXPanel is a Swing component able to display JavaFX and can be added to a MATLAB GUI using javacomponent (or Yair’s uicomponent or my jcontrol, which build on that).

M