You may store app preferences in the cloud (the backend data) or in a variable in the local storage of the device.
If you store the data in the local storage of the device the preferences will be avaible only to that particular device. Therefore if a user installs the app on different devices, then he will have to set these preferences twice as they are stored locally and not in the cloud. Still, this data will be available even if the device is offline (has no internet connection at all).
Whenever approach you choose, you will have to make modifications using the Code tab (not the Views service) as the Views service does not support it. The Views service is mostly aimed at creating as much as possible from the functionality and layout of the app from the start. However, after you get to the point where you need to make a lot of customization, it is best to switch to the Code tab and continue your development and updates there. After you do, you should stop using the Views service for the app in question, since a re-generation of its views will wipe your custom code (if they are outside the CUSTOM_CODE blocks).
Let me know if you need additional information.
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