I have a bottom nav with 4 fragments Home, Following, Notification, and Profile, there is no issue with the bottom navigation on backstack , but now for eg from profile fragment I jumped to a fragment called edit_profile which is not a part of the bottom nav and when press back I want that it should go back to the profile fragment but the backstack is taking me from edit_profile to directly home fragment
here is a recording link
I recently change my project from java to kotlin and I'm a beginner in kotlin
i really like the navigation of Pinterest and Instagram
Note:- All this code is automatically changed to kotlin (with some changes done manually ) , this issue was also with java and not after migrating to kotlin , Also if you want more reference of the code please tell me i will update the question
Code
MainActivity.kt // Bottom Nav
class MainActivity : AppCompatActivity() {
var bottomNavigationView: BottomNavigationView? = null
var integerDeque: Deque<Int> = ArrayDeque(3)
var flag = true
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO)
setContentView(R.layout.activity_main)
val window = this.window
window.statusBarColor = this.resources.getColor(R.color.black)
bottomNavigationView = findViewById(R.id.bottom_navigation_view)
integerDeque.push(R.id.nav_home)
loadFragments(Home_Fragment())
bottomNavigationView!!.selectedItemId = R.id.nav_home
bottomNavigationView!!.setOnNavigationItemSelectedListener(
BottomNavigationView.OnNavigationItemSelectedListener { item: MenuItem ->
val id = item.itemId
if (integerDeque.contains(id)) {
if (id == R.id.nav_home) {
integerDeque.size
if (flag) {
integerDeque.addFirst(R.id.nav_home)
flag = false
}
}
integerDeque.remove(id)
}
integerDeque.push(id)
loadFragments(getFragment(item.itemId))
false
}
)
}
@SuppressLint("NonConstantResourceId")
private fun getFragment(itemId: Int): Fragment {
when (itemId) {
R.id.nav_home -> {
bottomNavigationView!!.menu.getItem(0).isChecked = true
return Home_Fragment()
}
R.id.nav_following -> {
bottomNavigationView!!.menu.getItem(1).isChecked = true
return Following_Fragment()
}
R.id.nav_notification -> {
bottomNavigationView!!.menu.getItem(2).isChecked = true
return Notification_Fragment()
}
R.id.nav_profile -> {
bottomNavigationView!!.menu.getItem(3).isChecked = true
return Profile_Fragment()
}
}
bottomNavigationView!!.menu.getItem(0).isChecked = true
return Home_Fragment()
}
private fun loadFragments(fragment: Fragment?) {
if (fragment != null) {
supportFragmentManager.beginTransaction()
.replace(R.id.fragment_container, fragment, fragment.javaClass.simpleName)
.commit()
}
}
override fun onBackPressed() {
integerDeque.pop()
if (!integerDeque.isEmpty()) {
loadFragments(getFragment(integerDeque.peek()))
} else {
finish()
}
}
Edit_Profile.kt // from this fragment i want to go back to the last fragment which should be the profile fragment
class Edit_Profile : Fragment() {
private var profilePhoto: CircleImageView? = null
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_edit_profile, container, false)
profilePhoto = view.findViewById(R.id.circleImageView)
initImageLoader()
setProfileImage()
val imageView = view.findViewById<ImageView>(R.id.backArrow)
imageView.setOnClickListener {
val newCase: Fragment = Profile_Fragment()
assert(fragmentManager != null)
val transaction = requireFragmentManager().beginTransaction()
transaction.replace(R.id.fragment_container, newCase)
transaction.addToBackStack(Profile_Fragment.toString())
transaction.commit()
}
return view
}
Edit
added a part of the transaction from Profile Fragment to Edit Profile
ProfileFragment.kt
editProfileButton!!.setOnClickListener(View.OnClickListener { v: View? ->
val edit_profile: Fragment = Edit_Profile()
requireActivity().getSupportFragmentManager()
.beginTransaction()
.add(R.id.fragment_container, edit_profile,"TAG")
.addToBackStack("TAG")
.commit()
})
Now you are managing the back stack through the integerDeque array.
BottomNavigationView fragment; you added its id to the array if it doesn't already exist.But since you pushed all those ids in the bottomNavigationView.setOnItemSelectedListener callback; then the integerDeque array only contains BottomNavigationView fragments ids.
And as the Edit_Profile fragment is not a part of BottomNavigationView fragments, then it won't be added/popped off the queue. Instead when you try to popup the back stack whenever the Edit_Profile fragment is shown; the normal behavior you manage in the onBackPressed() continues and the Profile_Fragment id will pop up from the queue making you return to the preceding fragment (Home_Fragment) in your mentioned example.
A little fix to this is to consider adding an id into the queue when you transact to Edit_Profile fragment so that this id is popped off the queue resulting in back to Profile_Fragment fragment.
You can do that with the fragment's id in order to make sure it's unique:
editProfileButton!!.setOnClickListener(View.OnClickListener { v: View? ->
val edit_profile: Fragment = Edit_Profile()
requireActivity().getSupportFragmentManager()
.beginTransaction()
.add(R.id.fragment_container, edit_profile,"TAG")
.addToBackStack("TAG")
.commit()
(requireActivity() as MainActivity).integerDeque.push(id) // <<<< pushing id to the queue
})
This should fix your problem.
setOnItemSelectedListener instead of setOnNavigationItemSelectedListener on the BNV as the latter is deprecated.true instead of false from setOnItemSelectedListener callback as this should consume the event and mark the BNV as selected.Edit_Profile transaction replace the fragment instead of adding it with add as already the container is consumed; and this would make you avoid overlapping fragments in the container.onBackPressed(); you'd replace loadFragments(..) with bottomNavigationView.selectedItemId = integerDeque.peek(); this could be lighter to reuse the same fragment instead of redoing the transaction.