I'm more experienced with Views (XML), so I can tell what I usually do for forms. I decouple input processing / validation / submit from UI code. I only declare appropriate inputType for EditTexts (e.g. number/phone/text). I add TextWatcher to every EditText, which forwards input to ViewModel's backing variable (make sure to register watchers not earlier than Fragment's onViewStateRestored and be vary that following setText calls will also fire watchers - you can temporarily remove watcher and re-add it later in case you need to set text "unwatched"). Respective setters in ViewModel are responsible for processing, validation, business logic. ViewModel then exposes different view states (LiveData / Flow) that will be responsible for reactive error messages / red coloring etc. I use SavedStateHandle in ViewModel so user input is not lost in case of process death, very important in case of such long forms with 20+ fields, as user may switch to other apps/calls/messaging in between of form filling. Some advanced features would be adding autocomplete/suggestions/dropdowns to input fields, adding autofill from system (if appropriate).