Trouble with creating classes

Hi!

First I have to shamefully admit that I have a very little experience with programming and I'm very new to classes in Matlab, so please bear with me :) My question is the following:

I want to have a class which has lets say a football player's name, number, acceleration, speed and position. The initial data I want to enter when creating the class with a constructor is the name,number and t,x,y,z, which are the time and raw acceleration in three axes. So far, so good. I know I can call the functions I have written in the class methods,but it seems that I'm not doing it right. For example the properties I want to have besides the initial ones are Data(which really is just a matrix of [t x y z], but I can't even manage to do that right!), Acceleration,Speed,Position. This is as far as I've come please don't laugh too much :)

Thanks in advance!

    classdef Players
      %UNTITLED Summary of this class goes here
      %   Detailed explanation goes here

      properties
          Number=0
          Name='';
          t=0
          x=0
          y=0
          z=0
      end % end properties

      properties ( SetAccess = private)
          Data
          Acceleration
          Speed
          Position
      end % end properties
      methods
          function pl = Players(Number,Name,t,x,y,z)
     if nargin > 0 % Support calling with 0 arguments
        pl.Number = Number;
        pl.Name = Name;
        pl.t = t;
        pl.x = x;
        pl.y = y;
        pl.z = z;
     end 
  end % Players
     function obj = set.Data(obj, value) 
             value=[pl.t pl.x pl.y pl.z];
     obj.Data= value;

     end
     function obj = set.Acceleration(obj, rot)
     [ Mb] = butterworth( pl.Data );
     [d,p,h]=calibration(Mb);
     rot=h*9.81;
     obj.Acceleration = rot;
      end
      function obj = set.Speed(obj, Mv)
          [Mv] = velocity(pl.t,pl.Acceleration);
           obj.Speed= Mv;
      end
      function obj = set.Position(obj, Mp)
          [Mp] = position(pl.t,pl.Speed); 
          obj.Position= Mp;
      end
  end % end methods
  end

P.S. Also if i use classes in a GUI do they need to be handle classes?

Answer 1

[per isakson]

With GUI you can use both handle and value classes. Handle classes and handles in Handle Graphic are not "connected". Many of the standard design patterns only works with handle classes.

One problem with you code is that in the methods you refer to properties with "name". It should be "obj.name". With Matlab one must refer to the object explicitely.

The Code Analyzer is happy with this code and the box is green. I prefer the word "this" to "obj".

    classdef Players
        %UNTITLED Summary of this class goes here
        %   Detailed explanation goes here

        properties
            Number=0
            Name='';
            t=0
            x=0
            y=0
            z=0
        end % end properties

        properties ( SetAccess = private)
            Data
            Acceleration
            Speed
            Position
        end % end properties
        methods
            function this = Players( Number, Name, t, x, y, z)
                if nargin > 0 % Support calling with 0 arguments
                    this.Number = Number;
                    this.Name = Name;
                    this.t = t;
                    this.x = x;
                    this.y = y;
                    this.z = z;
                end
            end % Players
            function this = get.Data(this)
                if nargin > 0
                    this.Data=[ this.t, this.x, this.y, this.z ];
                end
            end
    %         function rot = get.Acceleration( this )
    %             Mb = butterworth( this.Data );
    %             [ d, p, h ] = calibration( Mb );
    %             rot= h*9.81;
    %         end
            function Mv=get.Speed( this )
                Mv = velocity( this.t, this.Acceleration);
            end
            function Mp=get.Position( this )
                Mp = position( this.t, this.Speed );
            end
        end% end methods
    end

Answer 2

[Petya Popova]

Thanks!

I first copied by mistake my very first attempt that's why it didn't have any referencing :), but thanks again! I edited it now. Should I use set. or get. Also can I use something different than obj or this?

I use set and i'm not sure the situation got any better...i got from this:

>> N19=Players(19,'Ivanov',t,x,y,z)

N19 = 

    Players

    Properties:
            Number: 19
              Name: 'Ivanov'
                 t: [146x1 double]
                 x: [146x1 double]
                 y: [146x1 double]
                 z: [146x1 double]
              Data: []
      Acceleration: []
             Speed: []
          Position: []

    Methods

to this:

>> N19=Players(19,'Ivanov',t,x,y,z)

N19 = 

    Players

    Properties:
      Number: 19
        Name: 'Ivanov'
           t: [146x1 double]
           x: [146x1 double]
           y: [146x1 double]
           z: [146x1 double]

    Methods

[per isakson]

You can use any legal Matlab name for the object. However, "me", "self", "this" are used in other languages and will be recognized by other programmers. Chose one and stick to it.

[per isakson]

I guess set and get-methods should be used only when there is a good reason. get-methods can be a nuisance during development because they are called by tooltip and if there is an error in the method it will be triggered when one use tooltip.

[per isakson]

The name "obj" is useful for other objects, which are passed to a method.

Answer 3

[Petya Popova]

Solved it! Thanks again!