How to add badge to BottomNavigationView in Android

Question

I want to use BottomNavigationView view for set some fragments !

But I want to set badge ( circle background with text ) to one of item of BottomNavigationView ! For this job, I write below codes. In my codes, it works for the first time. but when update badge text , then not show badge text just show circle background without any text!! Why when update badge number hide text count?!

My activity codes :

class MainActivity : AppCompatActivity() {

    private lateinit var disposable: Disposable

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.main_activity)
        setupNavigation()

        bottomNavigationView.selectedItemId = R.id.tab

        disposable = RxBus.listen(RxEvent.EventAddPerson::class.java).subscribe {
            badgeBottomNavBar(it.personName.toInt())
        }
    }

    private fun setupNavigation() {
        val navController = Navigation.findNavController(this, R.id.mainNavigationFragment)
        //setupActionBarWithNavController(this, navController)
        NavigationUI.setupWithNavController(bottomNavigationView, navController)
    }

    override fun onSupportNavigateUp() = Navigation.findNavController(this, R.id.mainNavigationFragment).navigateUp()

    private fun badgeBottomNavBar(count: Int) {
        val bottomNavigationMenuView = bottomNavigationView.getChildAt(0) as BottomNavigationMenuView
        val v = bottomNavigationMenuView.getChildAt(2)
        val itemView = v as BottomNavigationItemView

        val view = LayoutInflater.from(this).inflate(R.layout.notification_test, itemView, true)
        val badgeText: TextView = view.findViewById(R.id.notificationsBadge)
        badgeText.text = count.toString()
    }

    override fun onDestroy() {
        super.onDestroy()
        if (!disposable.isDisposed) disposable.dispose()
    }
}

Fragment codes :

class NotificationDetails : Fragment() {

    override fun onCreateView(inflater: LayoutInflater,
                              container: ViewGroup?,
                              savedInstanceState: Bundle?): View? {

        return inflater.inflate(R.layout.fragment_notification_details, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        arguments?.let {
            val passedArguments = NotificationDetailsArgs.fromBundle(it)
            notificationDetailsLabel.text = passedArguments.notificationId
        }

        notificationDetailsLabel.setOnClickListener {
            RxBus.publish(RxEvent.EventAddPerson(editText.text.toString()))
        }
    }
}

How can i fix it?

Answer 1

Your problem is very simple my friend!
You use bottomNavBar options with locally variable!
First you should initialize this variable globally and then use it!

Such as below codes :

class MainActivity : AppCompatActivity() {

    private lateinit var disposable: Disposable
    private lateinit var bottomNavigationMenuView: BottomNavigationMenuView
    private lateinit var itemView: BottomNavigationItemView
    private lateinit var view: View
    private lateinit var badgeText: TextView

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.main_activity)
        setupNavigation()

        bottomNavigationView.selectedItemId = R.id.tab5

        bottomNavigationMenuView = bottomNavigationView.getChildAt(0) as BottomNavigationMenuView
        val v = bottomNavigationMenuView.getChildAt(2)
        itemView = v as BottomNavigationItemView

        view = LayoutInflater.from(this).inflate(R.layout.notification_test, itemView, true)
        badgeText = view.findViewById(R.id.notificationsBadge)

        //Set badge
        badgeBottomNavBar("15")

        disposable = RxBus.listen(RxEvent.EventAddPerson::class.java).subscribe {
            badgeBottomNavBar(it.personName)
        }
    }

    private fun setupNavigation() {
        val navController = Navigation.findNavController(this, R.id.mainNavigationFragment)
        NavigationUI.setupWithNavController(bottomNavigationView, navController)
    }

    override fun onSupportNavigateUp() = Navigation.findNavController(this, R.id.mainNavigationFragment).navigateUp()

    private fun badgeBottomNavBar(count: String) {
        badgeText.text = count
    }

    override fun onDestroy() {
        super.onDestroy()
        if (!disposable.isDisposed) disposable.dispose()
    }
}

I hope help you