Make a TabBar inside a specific NavBar fragment - android-studio

Question

my app use bottomNavBar with 3 fragments [Settings / Home / Gallery].
Now I'm trying to make a TabBar with 3 new Tabs inside of "Settings". [setting01 / setting02 / setting03]
I followed carefully this tutorial : https://www.youtube.com/watch?v=qfFANw7nPMU
and I used viewPager2 when the video uses viewPager.
but I'm still stuck in MainActivity.kt because for some reasons these two line (from the tutorial) didn't work for me :
viewPager2.adapter = PageAdapter(supportFragmentManager)
tabLayout.setupWithViewPager(viewPager2)
here is my entire MainActivity.kt file :
package com.example.appname
import android.os.Bundle
import com.google.android.material.bottomnavigation.BottomNavigationView
import androidx.appcompat.app.AppCompatActivity
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController
import com.example.appname.ui.settings.PageAdapter
import kotlinx.android.synthetic.main.fragment_settings.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val navView: BottomNavigationView = findViewById(R.id.nav_view)
val navController = findNavController(R.id.nav_host_fragment)
val appBarConfiguration = AppBarConfiguration(setOf(
R.id.navigation_settings, R.id.navigation_swapper, R.id.navigation_gallery))
setupActionBarWithNavController(navController, appBarConfiguration)
navView.setupWithNavController(navController)
viewPager2.adapter = PageAdapter(supportFragmentManager)
tabLayout.setupWithViewPager(viewPager2)
}
}
I'm almost certain that this error exists because these two lines should be somewhere else because of the particular situation of my application.
To find yourself in a situation similar to mine I recommend you to start a new project under android studio using the template "Bottom Navigation Activity" and then follow the tutorial.

Answer 1

A friend of mine give me the solution.
Nothing new in MainActivity.kt like I was thinking.
Here is the new code to make tabBar in the Settings fragment :
settingFragment.kt
class SettingsFragmentAdapter(fragment: Fragment) : FragmentStateAdapter(fragment) {
private val fragments =
listOf(
fragment_setting_teams(),
fragment_setting_general(),
fragment_setting_movies()
)
override fun getItemCount(): Int = fragments.size
override fun createFragment(position: Int): Fragment = fragments[position]
}
class SettingsFragment : Fragment() {
private lateinit var settingsViewModel: SettingsViewModel
private lateinit var settingsAdapter: SettingsFragmentAdapter
private lateinit var viewPager: ViewPager2
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val tabLayout = view.findViewById<TabLayout>(R.id.tabLayout)
settingsAdapter =
SettingsFragmentAdapter(
this
)
viewPager = view.findViewById(R.id.viewPager2)
viewPager.adapter = settingsAdapter
TabLayoutMediator(tabLayout, viewPager) { tab, position ->
when (position) {
0 -> tab.text = "Teams"
1 -> tab.text = "General"
2 -> tab.text = "Movies"
}
}.attach()
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
settingsViewModel =
ViewModelProviders.of(this).get(SettingsViewModel::class.java)
val root = inflater.inflate(R.layout.fragment_settings, container, false)
return root
}
}