Is it possible to assign keyboard shortcuts to trigger certain parts of my app in app designer, and if so, how?

I was wondering if it's possible to assign user defined keyboard shortcuts to parts of the app in app designer.

For example,using a menu item with ctrl+L, or simply just L. Not sure if this is possible, but if anyone knows, please share

Thanks!

[Mohammad Sami]

yes. you need to set a keypressfcn for the uifigure.

Answer 1

[rbme17]

04/07/2020: Implement Basic Key Press Functionality

I found out what to do based on Mohammad Sami's reply to my question.

(1) Go to callbacks in the app designer window for the entire UIFigure in deisgn view

(2) In the 'keyboard' menu, go to KeyPressFcn and select <add KeyPressFcn callback> (should be at the top of the list). This will create a callback in code view for you to edit.

(3) In the callback, there will be a preset variable called 'key'. Set up a swtich/case for which key's you'd like to perform specific functions. 'key' will always providing the physical key pressed as a string in lowercase letters.

% Key press function: UIFigure
function UIFigureKeyPress(app, event)
key = event.Key;

switch key
    case 'p'
        app.PlotMyData(app);
        app.Message.Value = key; % return key value
    case 'f1'
        app.ChangeData(app);
        app.Message.Value = key;
    case 'shift'
        app.ChangeColor(app);
        app.Message.Value = key;
    case '1'
        app.Message.Value = 'Pressed 1';
end
end

(4) As a side note for those who may not know, you can get a look at what the value of 'key' will be by creating a text box, and setting the value to key (shown above). This will help you designate keys for functions you may have.

Hope this helps someone else as well.

Edit (10/27/2020): Use Modifiers (e.g. shift Q, control P, etc...) along with Key Press

The following code shows an example of how to use modifiers such as 'shift', 'control', and 'alt' with the keypress functionality.

You don't have to use a switch/case and can accomplish the same goal by using if/elseif/else of whatever you'd like. This is just one way I thought of doing this. This allows for things like ctrl+q, shift+p, etc.

Make sure to press them quickly in succession or it will only register one key press, either the modifier or the letter/number/etc. Hope this helps!

% Key press function: UIFigure
function UIFigureKeyPress(app, event)
key = event.Key;

if isequal(event.Modifier,'shift')
    switch key
        case 'f1'
            app.ChangeData(app);
            app.Message.Value = key; 
        case ...
             ...
    end
elseif isequal(event.Modifier,'control')
    switch key
        case 'q'
            app.Message.Value = 'quitting'; % write to text area of GUI
            % insert a quit function % 
        case ...
             ...
    end
else % no modifier used (e.g. just a key press, 'k','f4', etc.)
    ...
end
end

[Veena Chatti]

Thanks for sharing, I found it very helpful.

Do you know how to use key combinations for when two keys need to be pressed? Like "Command+Q" for 'Quit'?

[Veena Chatti]

Also, I'm not sure I understand fully what "app.Message.Value" represents here?

[William Warriner]

Hi Veena, check out here in the docs:

https://www.mathworks.com/help/matlab/ref/matlab.ui.figureappd-properties.html#mw_67a01097-0247-433a-bb73-d50824d9c9c6

The "event" parameter has a "Modifier" property which has the modifier buttons in a cell array, such as shift and ctrl.

[rbme17]

Hi Veena,

William is correct. 'event' has multiple fields within the structure. All of the modifiers, such as 'shift', 'control', 'command', etc must be spelled out completely in all lowercases.

Also, to answer your other question, 'app.Message.Value' is how I write the character value of the key pressed to the GUI so I can check which keys I'm pressing (to make sure it works). That is the name I must have assigned to a 'Text Area' component.

I edited my original answer, hopefully that helps you!

[Atharva Sule]

Hi, is it possible to disable keys like "Tab" which have specific in-built functions by default? I don't want to allow the users of the app to toggle to the next field by using Tab button on the keyboard.

[ol Poot]

the code above worked amazingly for me. Except, for me, the modified keys need " " not ' '

[Tom Parish]

I am trying to use this same method to update Values from exiting buttons.

Is the app.ChangeData a button or a callback function?

In my usecase i have a State button app.STOPbutton and a callback app.StopButtonValueChanged. I am trying to update a global variable with a keyboard press that is already actiavted when the State button app.STOPButton is pressed through the app.StopButton Changed callback.

Any guidance is appreciated.

function figure1KeyPress(app, event)
            key = event.Key;

            switch key
            case 's'
                app.STOPButtonValueChanged(app);
                app.Message.Value = key; % return key value
            case 'o'
            app.SafetySwitchValueChanged(app);
            app.Message.Value = key; % return key value

            case 'r'
                app.RESUMEButton(app);
                app.Message.Value = key;
            end

end

Answer 2

[Abhisek Pradhan]

There is similar question in following link on configuring a GUI button to keypress. Hope it helps.https://in.mathworks.com/matlabcentral/answers/12034-gui-button-with-keyboard-shortcut

[rbme17]

Hi Abhisek Pradhan,

Thanks for your response!

It seems like the solution provided implements 'uicontrol', which according to the MATLAB help database, is only suited for GUIDE. I am working with app designer, so I don't think it'll work for me.