Why can't parameters be passed to a fragment's constructor?

It is not possible to pass parameters directly to a fragment's constructor due to Android's lifecycle and state restoration process. Fragments can be recreated by the system (for example, during configuration changes or low memory conditions), and in such cases, their default constructor without any arguments will be called. If you pass parameters through the constructor, they will be lost during recreation, which can lead to application crashes or incorrect behavior.

The correct way to pass data to a fragment is to use a Bundle object and the setArguments() method. This bundle is saved and restored by the system during fragment recreation.

Example:

Passing data:

// Creating a fragment with arguments
val fragment = MyFragment()
val bundle = Bundle()
bundle.putString("key", "value")
fragment.arguments = bundle

// Replacing the fragment
supportFragmentManager.beginTransaction()
    .replace(R.id.fragment_container, fragment)
    .commit()

Retrieving data inside the fragment:

// Inside the fragment, for example, in onCreate() or onViewCreated()
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    arguments?.let {
        val value = it.getString("key")
        // Use "value"
    }
}

This ensures the preservation and restoration of the passed data during automatic fragment recreation by the system.