How to initialize toggle line visibility as off?

Hi,

I'm plotting graphs in an UIAxes, and I have used the following the following function (also see the attached .mlapp file) to enable toggling between data by using the legends. However, I cannot figure out how to initialize the legends as clicked at startup? Can anyone help?

        function legendBDCB(app,~,evnt)
        % This function uses the postion data from where the legend was
        % clicked to toggle a line on/off
        
        % First, get all of the lines
        lines = app.UIAxes.Children;
        
        % Next, create segments based off of the number of lines. Based on
        % where the user clicked in the legend, we will assign that click
        % location to a line. This call generates a grid of equally spaced
        % ranges, with the number of ranges equaling the number of lines
        click_locations = linspace(0,1,numel(lines)+1);
        
        % Get corresponding bin based on the 2nd value of
        % evnt.IntersectionPoint. This corresponds to the vertical distance
        % within the legend, which we can use to identify what line
        % (roughly) in the legend was clicked
        line_num = discretize(evnt.IntersectionPoint(2),click_locations);
        
        % Set the visiblility of the corresponding line 'off' or 'on'
        relevant_line = lines(line_num);
        if strcmp(relevant_line.Visible,'on')
            relevant_line.Visible = 'off';
        else
            relevant_line.Visible = 'on';
        end
        
        end

This is the link for the code:

https://se.mathworks.com/matlabcentral/answers/475493-how-can-i-use-a-legend-in-app-designer-to-toggle-line-visibility-on-and-off

Answer 1

[Shiva Kalyan Diwakaruni]

Hi,

You can open the LegendLineVisibilityApp.mlapp in code view and add a startupFcn in like below and give legendBDCB as callback handle to ButtonDownFcn

methods (Access = private)

% Code that executes after component creation

function startupFcn(app)

plot(app.UIAxes, magic(5));

l = legend(app.UIAxes);

[app.UIAxes.Children(:).Visible] = deal('off','off','off','off','off');

% Here, we set the ButtonDownFcn, in place of the ItemHitFcn

% which is disabled for UIFigures/App Designer

l.ButtonDownFcn = @app.legendBDCB;

end

end

Hope it helps.