Is it possible to be sure that changing settings will invoke the user constructor of the fragment?

No, it cannot be guaranteed that changing the settings will invoke the fragment's user-defined constructor.

In Android, the system may recreate fragments using the parameterless (default) constructor, especially when restoring state after a configuration change (e.g., screen rotation).

Therefore, it is recommended to:

• Use the default parameterless constructor.
• Pass parameters via a Bundle using the setArguments() method.
• Retrieve parameters in the onCreate() or onCreateView() method from getArguments().

This ensures the fragment's state is correctly restored by the system.

Example:

class MyFragment : Fragment() {
    companion object {
        fun newInstance(param: String): MyFragment {
            val fragment = MyFragment()
            val args = Bundle()
            args.putString("param_key", param)
            fragment.arguments = args
            return fragment
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val param = arguments?.getString("param_key")
        // Use param
    }
}