डायलॉगफ्रैगमेंट श्रोता

मेरे पास एक श्रोता के साथ डायलॉगफ्रैगमेंट है जब मेरे टुकड़े में फ़ंक्शन को कॉल करने के लिए एक बटन क्लिक किया जाता है।

जब मैं सकारात्मक बटन पर क्लिक करता हूं तो मुझे lateinit property listener has not been initialized मिल रहा है।

DialogFragment

class CreateCollectionDialog: DialogFragment() {
    lateinit var listener: CreateCollectionDialogListener

    interface CreateCollectionDialogListener {
        fun onDialogPositiveClick(dialog: DialogFragment, collectionName: String)
        // fun onDialogNegativeClick(dialog: DialogFragment)
    }

    override fun onAttachFragment(childFragment: Fragment) {
        println("onAttachFragment")
        super.onAttachFragment(childFragment)
        listener = context as CreateCollectionDialogListener
        println(listener)
    }

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        return activity?.let {
            val builder = AlertDialog.Builder(it)
            val inflater = requireActivity().layoutInflater
            builder.setView(inflater.inflate(R.layout.dialog_collection, null))
                .setPositiveButton("Create", DialogInterface.OnClickListener { dialog, id ->
                    // Create new collection
                    var newCollectionName = view?.findViewById<EditText>(R.id.newCollectionName)?.text.toString()
                    if (!newCollectionName.equals("") && newCollectionName != null) {
                        listener.onDialogPositiveClick(this, newCollectionName)
                    }
                })
                .setNegativeButton("Cancel", DialogInterface.OnClickListener { dialog, id ->
                    // User canceled dialog
                    // listener.onDialogNegativeClick(this)
                })
            builder.create()
        }?: throw IllegalStateException("Activity cannot be null")
    }

    override fun onStart() {
        super.onStart()
        val positive: Button = (dialog as AlertDialog?)!!.getButton(AlertDialog.BUTTON_POSITIVE)
        positive.setTextColor(resources.getColor(R.color.topColor))

        val negative: Button = (dialog as AlertDialog?)!!.getButton(AlertDialog.BUTTON_NEGATIVE)
        negative.setTextColor(Color.RED)
    }
}

टुकड़ा

class CollectionsFragment: Fragment(), CreateCollectionDialog.CreateCollectionDialogListener {
     override fun onOptionsItemSelected(item: MenuItem): Boolean {

        when (item.itemId) {
            R.id.add -> {
                val createDialog = CreateCollectionDialog()
                createDialog.show(fragmentManager!!, "")
                return true
            }
        }
        return false
    }

    override fun onDialogPositiveClick(dialog: DialogFragment, collectionName: String) {
        addNewCollection(collectionName)
    }
}