MaterialAlertDialogBuilder crashes on custom view editText

Question

The AlertDialog(Material) crashes when tries to read the editText content.

The AlertDialog:

MaterialAlertDialogBuilder(activity)
            .setTitle(title)
            .setMessage(message)
            .setView(R.layout.dialog_settings_entry)
            .setPositiveButton(getString(R.string.text_change)) { dialog, which ->
                etUserInput.hint = message
                sgr = etUserInput.text.toString() // << crashes here
                dialog.dismiss()
            }
            .setNegativeButton(getString(android.R.string.cancel)) { dialog, _ ->
                dialog.dismiss()
            }
            .show()

On clicking the positive button results as follows:

    java.lang.IllegalStateException: etUserInput must not be null
        at com.home.profile.SettingsFragment$buildAlertDialog$1.onClick(SettingsFragment.kt:332)
        at androidx.appcompat.app.AlertController$ButtonHandler.handleMessage(AlertController.java:167)

The etUserInput is simple editText in a seperate layout. Unsure the crash reason. Would appreciate any insight into it or any helpful Material samples.

Answer 1

Cast the DialogInterface to an AlertDialog and then use findViewById.

Kotlin:

val et = (dialog as? AlertDialog)?.findViewById<EditText>(R.id.etUserInput)
val text = et?.text.toString()

--

Java:

EditText et = ((AlertDialog)dialog).findViewById(R.id.etUserInput);
String text = et.getText().toString();

--

MaterialAlertDialogBuilder(activity)
            .setTitle(title)
            .setMessage(message)
            .setView(R.layout.dialog_settings_entry)
            .setPositiveButton(getString(R.string.text_change)) { dialog, which ->
                val text = (dialog as? AlertDialog)?.findViewById<EditText>(R.id.etUserInput)?.text?.toString()

                dialog.dismiss()
            }
            .setNegativeButton(getString(android.R.string.cancel)) { dialog, _ ->
                dialog.dismiss()
            }
            .show()