Issue with Key Press Events in App Designer Plot

I encountered an issue while developing the App Designer application. The plot of detection points using the plot function is not capturing key press events when the plot is paused. I've tried various approaches, but the control is not passing to the key press callbacks.

If you have any insights or suggestions, please let me know

Answer 1

[Shubham]

Hi Swapna,

In MATLAB App Designer, using "pause" can block key press events because it halts code execution and UI interaction. Here's how to address this issue:

• Replace "pause()" with a loop that checks for key presses while updating the plot.
• Use "drawnow" to process UI events and keep the interface responsive. Here's a simple implementation:

function plotWithKeyPressHandling(app)
    % Plot some data
    x = 1:10;
    y = rand(1, 10);
    plot(app.UIAxes, x, y, 'o');

    % Responsive loop for key press handling
    duration = 10;  % Duration in seconds
    startTime = tic;  % Start timer
    
    while toc(startTime) < duration
        drawnow;  % Process events, including key presses
    end
end

• Ensure "WindowKeyPressFcn" is set for the " UIFigure" to capture key events.

Kindly refer to the following documentation links for more information:

• drawnow: https://mathworks.com/help/releases/R2021b/matlab/ref/drawnow.html
• pause: https://mathworks.com/help/releases/R2021b/matlab/ref/pause.html

Hope this helps!