Custom painter Does not change when the listview tile changes

Currently implementing the custom slider based on the thermostats in the room, but the problem is when I change the above tile in the listview the custom painter does not repaint the slider with the selected temperature. Added the image that will give the view

Below is the git repository: https://github.com/sagaracharya24/SampleApp.git

Let me know if any wrong I am doing , I think it is kind of small change but I am not getting it.

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