double-click on "uilistbox" App designer

Hallop everyone,

How can I execute a double-click on ListBox in App Designer?

Thank you in Advance

Answer 1

[Kevin Chng]

Up to R2019b, app designer don’t have this feature,

It is because if you click on the selected item, no event will be triggered. Therefore, we could say only single click is allowed under this limitaion.

You can use button to replace list box. [toggle button group will behave same as list box, so you could not use this], use the 'normal' button for this.

For example :

Step 1 : For example : 3 selection: Create 3 button

Step 2 : Create callback function for each of them (it is a bit tedious, I have 3 button, then I have 3 callback function)

Step 3: Create private function click

Step 4 : here you go:

(Single Click the button, it turns blue)

(Double Click the button, it turns red)

You might have further question about ‘how’and ‘where’ could you put your algorithm:

You could put your algorithm in the click function

Answer 2

[Chidvi Modala]

In guide, To make the double-click work you only need to write the code below in List box callback

 function listbox_Callback(hObject, eventdata, handles) 
 if strcmp(get(gcf,'selectiontype'),'open')  
  % here you write write code, which you wanna be executed afer double-click
 end

In App designer, associate the below function with ValueChangedFcn callback of the List Box.

function clickcallback(obj,evt)
persistent chk
if isempty(chk)
      chk = 1;
      pause(0.5); %Add a delay to distinguish single click from a double click
      if chk == 1
          fprintf(1,'\nI am doing a single-click.\n\n');
          chk = [];
      end
else
      chk = [];
      fprintf(1,'\nI am doing a double-click.\n\n');
end

[joe]

Hi Chidvi Modal,

I've already tried that code for App designer but it doesn't work.

the code works like this: the second click must be on a different item as the first.

so I want to click on the same item double-click.

the function "ValueChangedFcn " will not react , if the same item tweece clicked because of the value (in this case second item) doesn't changed.

but for GUIDE your code works properly.

Thank you in Advance #Chidvi Modala

[KAI LUO]

I have a similar problem. Have you solved this problem?

[minlei qin]

Hello, I also encountered the same problem, after trying the above code can only achieve a second click must be different from the first click. So I want to double-click on the same item, how do I solve it？

[Huy Dinh Quang]

This problem can be solved by reset the value of the listbox after the first call. Here is the modified version

function clickcallback(obj,evt)
persistent chk
if isempty(chk)
      chk = 1;
      pause(0.5); %Add a delay to distinguish single click from a double click
      tempValue = app.FileListBox.Value;% if you want to use this value later 
      app.FileListBox.Value = {};
      if chk == 1
          fprintf(1,'\nI am doing a single-click.\n\n');
          chk = [];
          app.FileListBox.Value = tempValue;
      end
else
      chk = [];
      fprintf(1,'\nI am doing a double-click.\n\n');
end

[Markus Leuthold]

What I don't understand is why such an ugly workaround is needed now that the App Designer was written from scratch. Why didn't Mathworks add callbacks for mouse button pressing/clicking/double-clicking like e.g Qt is doing? These kind of callbacks are needed to do a halfway serious app. It's a pity Mathworks missed this unique chance to really cleanup the mess from GUIDE.

[Chidvi Modala]

I have heard that this issue is known and the concerned parties may be investigating further.

[Brett Mther]

This solution doesn't work for my application. If I double click on a ListBoxItem that is already selected, the ValueChangedFcn callback doesn't fire.

[Ahmet Gökhan POYRAZ]

@Brett Mther it doesn't work for my application too.