Hi Juan,
It is possible to shift focus only between certain components in MATLAB App Designer by coding the actions that the “Tab” key should perform in the window key press callback of the “UIFigure”.
Here are the steps to do it:
1. Create two private properties ‘editFields’ and ‘curEditFld’ to the class of the app. The ‘editFields’ property will store the desired UI Components we want to limit the focus to. The ‘curEditFld’ property will be used to index into the desired components.
properties (Access = private)
editFields;
curEditFld;
end
2. Initialize them in the startup function. Since it is required that the focus be limited to “EditField” components, we store them as a list in the ‘editFields’ property. For this example, there are 4 “EditField” components.
function startupFcn(app)
app.editFields = [app.EditField1, app.EditField2, app.EditField3, app.EditField4];
app.curEditFld = -1;
end
3. Now in the “UIFigureWindowKeyPress“ callback of “app.UIFigure”, specify how to handle “Tab” key press. Perform modular addition by '1' on the ‘curEditFld’ property and use it to index into the list of “EditField” components to get the component to be focused. In a similar way, handle cases like pressing “Shift+Tab” and using the mouse to randomly set the focus on specific components.
function UIFigureWindowKeyPress(app, event)
if strcmp(event.Key, "tab")
if size(event.Source.CurrentObject) ~= [0 0]
% Handle cases where user manually changes the current
% object through mouse click
actualIndex = find(app.editFields == event.Source.CurrentObject);
if(actualIndex-1~=app.curEditFld)
app.curEditFld=actualIndex-1;
end
end
if isempty(event.Modifier) % Tab : Move forward
app.curEditFld = mod(app.curEditFld+1,length(app.editFields));
elseif strcmp(event.Modifier{:},'shift') % Shift+Tab : Move backward
app.curEditFld = mod(app.curEditFld-1,length(app.editFields));
end
% Set the focus and current object to desired component
focus(app.editFields(1+app.curEditFld))
event.Source.CurrentObject = app.editFields(1+app.curEditFld);
end
end
This will “override” the default behavior of pressing “Tab”.
Please refer to the documentation links below to understand more on the properties and functions used:
- “CurrentObject”: https://www.mathworks.com/help/releases/R2023a/matlab/ref/matlab.ui.figureappd-properties.html?searchHighlight=currentObject
- “focus”: https://www.mathworks.com/help/releases/R2023a/matlab/ref/matlab.ui.figure.focus.html
- “event.Key” and “event.Modifier”: https://www.mathworks.com/help/releases/R2023a/matlab/ref/matlab.ui.figure-properties.html?searchHighlight=KeyPressFcn
I hope it helps!
