Kotlinで開始時とHome選択時にWeb表示

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding

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

        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        val navView: BottomNavigationView = binding.navView

        val navController = findNavController(R.id.nav_host_fragment_activity_main)
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        val appBarConfiguration = AppBarConfiguration(
            setOf(
                R.id.navigation_home,, R.id.navigation_notifications
            )
        )
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)
    }
}

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding

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

        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        val navView: BottomNavigationView = binding.navView

        val navController = findNavController(R.id.nav_host_fragment_activity_main)
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        val appBarConfiguration = AppBarConfiguration(
            setOf(
                R.id.navigation_home, R.id.navigation_notifications
            )
        )
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)

        val url = "https://www.google.com"
        val intent = Intent(Intent.ACTION_VIEW)
        intent.data = Uri.parse(url)
        startActivity(intent)
    }
}

class HomeFragment : Fragment() {

    private lateinit var homeViewModel: HomeViewModel
    private var _binding: FragmentHomeBinding? = null

    // This property is only valid between onCreateView and
    // onDestroyView.
    private val binding get() = _binding!!

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        homeViewModel =
            ViewModelProvider(this).get(HomeViewModel::class.java)

        _binding = FragmentHomeBinding.inflate(inflater, container, false)
        val root: View = binding.root

        val textView: TextView = binding.textHome
        homeViewModel.text.observe(viewLifecycleOwner, Observer {
            textView.text = it
        })
        return root
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}

class HomeFragment : Fragment() {

    private lateinit var homeViewModel: HomeViewModel
    private var _binding: FragmentHomeBinding? = null

    // This property is only valid between onCreateView and
    // onDestroyView.
    private val binding get() = _binding!!

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        homeViewModel =
            ViewModelProvider(this).get(HomeViewModel::class.java)

        _binding = FragmentHomeBinding.inflate(inflater, container, false)
        val root: View = binding.root

        val textView: TextView = binding.textHome
        homeViewModel.text.observe(viewLifecycleOwner, Observer {
            textView.text = it
        })

        val url = "https://www.google.com"
        val intent = Intent(Intent.ACTION_VIEW)
        intent.data = Uri.parse(url)
        startActivity(intent)

        return root
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}