CODEWITHSUNDEEP
arraysmatlaboop
Christoph
Christoph

Reputation: 333

Matlab OOP array of objects class

I'd like to understand how Matlab works with array objecs. I've read several posts and the Matlab help for this topic, but I still don't understand it completely.

Let's take a use case: I'd like to manage several measurement channels (the amount of channels can vary). Each measurement channel is an object with several properties. Now I'd like to have a class handling the channels (channelHandler.m). In this class I can simply add a new channel to the array (later on there might be bore functionality).

So what I've tried so far:

1) create the measurementChannel.m class In the constructor I've only set the channel name so far without data.

classdef measurementChannel
%CHANNEL holds an instance of a single channel

properties
    channelData
    channelName = strings
    channelUnit = strings
    channelDataLength    
    channelOriginMeasurementFile
end

methods
    function obj = channelTest(channelName)
        if nargin > 0
            obj.channelName = channelName;
        end
    end
end

end

To test this class I tried this:

channel(1) = measurementChannel('channelA');
channel(2) = measurementChannel('channelB');
channel(1).channelName
channel(2).channelName

which was working well.

2) Now I've created the channelHandler class:

classdef channelHandler

properties (Access = public)
    channelArray
end

methods (Access = public)

    function addChannel(obj, Name)

        testobj = measurementChannel();

        testobj.channelName = Name;

        obj.channelArray = [obj.channelArray testobj];

    end

end

and access this by using the following commands:

createChannels = channelHandler();

createChannels.addChannel('channel1');
createChannels.addChannel('channel2');

createChannels.channelArray(1).channelName
createChannels.channelArray(2).channelName

this fails because channelArray is not defined as an array and will give an error accessing channelArray(2). So I also tried to initialize the array (but then I need to know the amount of channels).

so my questions are: a) do I really need to initialize an array of objects? b) how can I fix the channelHandler class to add objects to the array?

Upvotes: 1

Views: 137

Answers (1)

Suever
Suever

Reputation: 65430

The issue is that you are not inheriting from the handle class and therefore the modifications made within addChannel alter a copy of your object rather than the object itself. If you inherit from handle, the code that you have pasted will work just fine.

classdef channelHandler < handle

Upvotes: 1

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