How are data stored in Activity during a configuration change, besides using the Bundle object?

In addition to saving state through the Bundle object in the onSaveInstanceState and onRestoreInstanceState methods, in Android, you can use:

• ViewModel from Android's architecture components. ViewModel lives longer than the Activity during configuration changes and retains data without losing it when the Activity is recreated.

• Retain Fragment — a fragment with setRetainInstance(true) that is preserved during Activity recreation (deprecated approach).

• Saving data in persistent storage (e.g., SharedPreferences, database) if data needs to be retained between sessions.

Example of using ViewModel:

class MyViewModel : ViewModel() {
    var data: String? = null
}

class MyActivity : AppCompatActivity() {
    private lateinit var viewModel: MyViewModel

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        viewModel = ViewModelProvider(this).get(MyViewModel::class.java)
        // Use viewModel.data, it will be preserved during configuration changes
    }
}

Thus, ViewModel is the preferred way to save data during configuration changes without using Bundle.