ChartContainer is broken?

Hi all,

Since R2020a, class properties, provided by the class constructor are assigned after the setup method runs, see https://www.mathworks.com/help/matlab/ref/matlab.graphics.chartcontainer.chartcontainer.setup.html#mw_892e1871-5986-41cf-b037-396fa9a9adbf

That means, I can't create plots that rely somehow on external information, provided by the user via constructor. An easy example would be this:

The user provides a timetable. Each column should be plotted to its own subplot:

classdef BrokenChartClass < matlab.graphics.chartcontainer.ChartContainer
    properties
        Data timetable
    end
    
    properties (Access = private)
        NumSubplots = 1
        DataAxes
        DataLines
    end
    
    methods
        function obj = BrokenChartClass(T)
            arguments
                T timetable
            end
            
            [e-mail]();
            
            obj.NumSubplots = length(T.Properties.VariableNames); % create as many subplots as columns in data table
            obj.Data = T;
        end
    end
    
    methods (Access = protected)
        function setup(obj)
            tcl = getLayout(obj);
            obj.DataAxes = arrayfun(@(n)nexttile(tcl, n), 1:obj.NumSubplots);           
            obj.DataLines = arrayfun(@(hax)plot(hax, NaT, NaN), obj.DataAxes);
        end
        
        function update(obj) 
            % Extract the time data from the table.
            tbl = obj.Data;
            t = tbl.Properties.RowTimes;
            
            for k = 1:length(obj.DataLines)
                set(obj.DataLines(k), 'XData', t, 'YData', tbl{:,k})
            end      
        end
    end
end

%% test via
T = timetable((datetime():seconds(1):datetime+hours(1))',randn(3601,1),10*randn(3601,1)); % 3601 rows, 2 data cols
head(T)
BrokenChartClass(T(:,1)); % -> one subplot, makes sense
BrokenChartClass(T(:,1:2)); % -> one subplot (uses default value of NumSubplots), not as expected but documented

Could you please help me understanding this concept? Calling setup before assigning the properties makes it impossible to use it. I always have to create another mySetup function to be called in update which requires some flag like bool IsInitialized or so.

I can't believe that's the purpose of this class. What am I missing?

Thanks!

[Jan Kappen]

Addendum, suppose you want to embed the chart class into a panel or uifigure, you can specify the Parent property. But since it's not assigned in setup(), a default figure is opened when I call getLayout(). I'd need to remember the old parent and overwrite it in a second call to setup().

This renders the automatic call of setup completely useless. Did I get something wrong?!

[Jörn Froböse]

Same thing for me. Did you find any better solution than this workaround with mySetup?