How can I display enumeration value in MATLAB object

问题

Given the following two classes

classdef EnumClass

    enumeration
        enumVal1
        enumVal2
    end
end


classdef EnumDisplay

    properties
        enumValue = EnumClass.enumVal1
        numberValue = 1
    end
end

When displaying an EnumClass, the value is displayed:

>> E = EnumClass.enumVal1

E = 

    enumVal1

but when displaying EnumDisplay in the command window, the enumeration value is suppressed, and only the array size and class are displayed.

>> C = EnumDisplay()

C =

  EnumDisplay with properties:

      enumValue: [1x1 EnumClass]
    numberValue: 1

What is the easiest way to have the enumeration value displayed in the class property list. I.e. is there an easy and general way to have the class displayed as follows:

>> C = EnumDisplay()

C =

  EnumDisplay with properties:

      enumValue: enumVal1
    numberValue: 1

I suspect that this has something to do with inheriting from the matlab.mixin.CustomDisplay class somewhere, but I want this to be as general as possible, to limit the amount of coding i need to do for each enumeration class, and/or each class that has an enumeration value in a property.

Partial Solution

I was able to figure out a partial solution to this problem, but it is not quite satisfactory.

classdef EnumDisplay < matlab.mixin.CustomDisplay

    properties
        enumValue = EnumClass.enumVal1
        numberValue = 1
    end

    methods (Access = protected)
        function groups = getPropertyGroups(This)
            groups = getPropertyGroups@matlab.mixin.CustomDisplay(This);
            groups.PropertyList.enumValue = char(This.enumValue);
        end
    end
end

Now the display looks like:

>> C = EnumDisplay()

C = 

  EnumDisplay with properties:

      enumValue: 'enumVal1'
    numberValue: 1

This is almost there, but not quite. I don't want the enumerated value to be in quotations.

回答1:

Okay, well... this isn't the most elegant approach -- certainly not as elegant as using matlab.mixin.CustomDisplay -- but one possibility is to try to replicate that functionality yourself, in a way that gives you more control. Here is what I hacked together on the ferry...

classdef EnumDisplay

    properties
        enumValue = EnumClass.enumVal1
        numberValue = 1
    end

    methods
        function disp(This)
            cl = class(This) ;
            fprintf('  <a href="matlab:helpPopup %s">%s</a> with properties: \n\n',cl,cl) ;
            prop = properties(This) ;
            len = max(cellfun(@length,prop)) ;

            for ii = 1:numel(prop)
                if isnumeric(This.(prop{ii}))
                    fmt = '%g' ;
                else
                    fmt = '%s' ;
                end
                filler = char(repmat(32,1,4+len-length(prop{ii}))) ;
                fprintf('%s%s: ',filler,prop{ii}) ;
                fprintf(sprintf('%s \n',fmt),char(This.(prop{ii}))) ;
            end
        end
    end
end

Result:

>> C = EnumDisplay()

C = 

  EnumDisplay with properties: 

      enumValue: enumVal1 
    numberValue: 1

Only catch is that this may not be fully generic because I may not have appropriately covered all of the possible formats fmt. But if you are really desperate, maybe something like this will work.

来源：https://stackoverflow.com/questions/22152029/how-can-i-display-enumeration-value-in-matlab-object

标签

matlab

oop

enumeration