What design patterns were used in implementing the presentation layer at your previous workplace?

The following design patterns are often used in Android presentation layer:

• MVP (Model-View-Presenter) — separates presentation logic and business logic, where the Presenter manages interactions between the View and the Model.
• MVVM (Model-View-ViewModel) — the ViewModel binds data and logic to the View through Data Binding, simplifying UI updates.
• Observer — used for tracking data changes, for example, via LiveData or RxJava.

Example of using MVVM with LiveData:

class MyViewModel : ViewModel() {
    val data: MutableLiveData<String> = MutableLiveData()

    fun loadData() {
        // load data
        data.value = "Sample data"
    }
}

// In Activity or Fragment
viewModel.data.observe(this, Observer { value ->
    textView.text = value
})

These patterns help make the code more modular, testable, and maintainable.