onActivityCreated.kt

    override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)

        room_btn_salvar.setOnClickListener {
            val palestrante = Palestrante(
                palestrante = room_et_nome.text.toString(),
                tecnologia = room_et_tecnologia.text.toString(),
                topico = room_et_topico.text.toString()
            )

            launch {
                context?.let {
                    PalestranteDB.getDatabase(it).dao().salvar(palestrante)
                    Toast.makeText(it, "Cadastro com sucesso!", Toast.LENGTH_SHORT).show()
                }
            }
        }
        
    }