How to create the custom item of Bottomnavigationview Android?

I used tab layout with a custom view in it

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/mainTabBar"
        android:layout_width="match_parent"
        android:layout_height="48dp"
        android:layout_alignParentBottom="true"
        android:background="@color/colorPrimaryDark"
        app:tabGravity="fill"
        app:tabIndicatorHeight="0dp"
        app:tabMode="fixed"
        app:tabSelectedTextColor="@color/colorPrimary" />

    var mainPagerAdapter = MainPagerAdapter(supportFragmentManager!!)
        viewPager.setAdapter(mainPagerAdapter)
        viewPager.setOffscreenPageLimit(mainPagerAdapter.getCount())
        for (i in 0 until mainPagerAdapter.getCount()) {
            val tab = mainTabBar.newTab()
            val tabView = mainPagerAdapter.getTabView(i, this)
            tab.setCustomView(tabView)
            mainTabBar.addTab(tab)
        }
        val tab = mainTabBar.getTabAt(0)
        if (tab != null) {
            tab.select()
            val view = tab.customView
            mainPagerAdapter.changeColorOfTabView(view!!, true, this,tab.position)
        }
        viewPager.setCurrentItem(0)

        mainTabBar.addOnTabSelectedListener(object : TabLayout.OnTabSelectedListener {
            override fun onTabSelected(tab: TabLayout.Tab) {
                viewPager.currentItem = tab.getPosition()
                val view = tab.getCustomView()
                mainPagerAdapter.changeColorOfTabView(view!!, true, this@MainActivity, tab.position)
            }

            override fun onTabUnselected(tab: TabLayout.Tab) {
                val view = tab.getCustomView()
                mainPagerAdapter.changeColorOfTabView(view!!, false, this@MainActivity, tab.position)
            }

            override fun onTabReselected(tab: TabLayout.Tab) {}
        })

    fun getTabView(i: Int, context: Context): View {
//        val typeface = Typeface.createFromAsset(context.getAssets(), "fonts/Vazir-FD.ttf")
        val tabView = LayoutInflater.from(context).inflate(R.layout.tab_main, null) as LinearLayout

        val text = tabView.findViewById<TextView>(R.id.tabTextView)
        val icon = tabView.findViewById<ImageView>(R.id.drawableTop)
        text.setText(getPageTitle(i))
        text.setTextColor(context.getResources().getColor(R.color.white))
//        text.setTypeface(typeface)
        icon.setImageResource(getIconResId(i))

        if (i == 3) {
            tabView.isSelected = true
        }
        return tabView
    }

tab_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:paddingTop="10dp"
    android:orientation="vertical">

    <ImageView
        android:id="@+id/drawableTop"
        android:layout_width="30dp"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:adjustViewBounds="true" />

    <TextView
        android:id="@+id/tabTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/drawableTop"
        android:layout_centerHorizontal="true"
        android:textColor="@color/toggle_text_color_gray_red"
        android:textSize="11sp" />
</LinearLayout>

I have done the above task as the following approach, please have a look on the solution

Layout

 <android.support.design.widget.BottomNavigationView
            android:id="@+id/bottom_navigation"
            android:layout_width="match_parent"
            android:layout_height="60dp"
            android:layout_alignParentBottom="true"
            android:background="@color/header_color"
            app:itemIconTint="@color/white_color"
            app:itemTextColor="@color/white_color"
            app:menu="@menu/bottom_navigation" />  /// YOUR MENU ITEMS FOR THE BOTTOM NAVIGATION

Your badge count layout be like below

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/notificationsBadge"
        android:layout_width="25dp"
        android:layout_height="25dp"
        android:layout_gravity="top|center_horizontal"
        android:layout_marginLeft="10dp"
        android:layout_marginStart="10dp"
        android:background="@drawable/circle_red"
        android:gravity="center"
        android:padding="4dp"
        android:text=""
        android:textColor="@android:color/white"
        android:textSize="12sp" />
</FrameLayout>

And than after your badge drawable be like below

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    <solid android:color="@android:color/holo_red_light" />
    <size
        android:width="20dp"
        android:height="20dp" />
</shape>

And at the last, you need we need to inflate our badge layout into our MainActivity.java , where we use the BottomNavigationView, please check the following code for it.

    BottomNavigationMenuView mbottomNavigationMenuView =
            (BottomNavigationMenuView) mBinding.bottomNavigation.getChildAt(0);

    View view = mbottomNavigationMenuView.getChildAt(4);

    BottomNavigationItemView itemView = (BottomNavigationItemView) view;

    View cart_badge = LayoutInflater.from(this)
            .inflate(R.layout.profile_view,
                    mbottomNavigationMenuView, false);

    //// AND THAN SET THE COUNTER BADGE, AS FOLLOW
    ((TextView) cart_badge.findViewById(R.id.notificationsBadge)).setText("5");

    itemView.addView(cart_badge);

If you are using androidX , please refer below code :

  BottomNavigationView mbottomNavigationView =findViewById(R.id.navigation);

        BottomNavigationMenuView mbottomNavigationMenuView =
                (BottomNavigationMenuView) mbottomNavigationView.getChildAt(0);

        View view = mbottomNavigationMenuView.getChildAt(1);

        BottomNavigationItemView itemView = (BottomNavigationItemView) view;

        View cart_badge = LayoutInflater.from(this)
                .inflate(R.layout.notification_badge,
                        mbottomNavigationMenuView, false);

        itemView.addView(cart_badge);