Reconnecting to a Bluetooth device within a class

I have built a class to communicate with a Bluetooth device, setting one of the class properties as the Bluetooth object 's'. Within a class function that updates the device, I need to reset the device, which breaks the link with MATLAB. I've created a basic disconnect command that has worked thus far from outside the class.

function disconnect(obj)
    obj.s.delete;
    obj.s=[];
end

When I do this from inside the class function and then reconnect...

BTaddr=obj.s.Address;
BTchan=obj.s.Channel;

obj.s.delete;
obj.s=[];

obj.s=bluetooth(BTaddr,BTchan);

...the function continues to run as expected, but then the 'myDev.s' object is a "handle to deleted bluetooth" variable. I am then able to disconnect and reconnect outside of the class, but it seems unnecessarily messy. Is there something that I could do better to make this work as expected?

Answer 1

[Broy]

Hi @Brian,

The behavior you are describing, where the object properties revert to their previous state after the method finishes, suggests that your class is currently defined as a Value Class.

In MATLAB, modifications made to a Value Class inside a method are local to that method unless the modified object is returned. To ensure that the disconnection and reconnection persist outside the function, you need to define your class as a Handle Class.

You can do this by inheriting from the handle class in your classdef line:

classdef YourClassName < handle
    % Your properties and methods
end

Helpful Documentation for Comparison of Handle and Value Classes:

• https://www.mathworks.com/help/releases/R2024b/matlab/matlab_oop/comparing-handle-and-value-classes.html

Hope it helps.