NavigationBar Android/XML/Kotlin

navigationbarxml

MainActivity.kt:

package com.example.test

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.ArrayAdapter
import android.widget.Button
import android.widget.ListView
import com.google.android.material.bottomnavigation.BottomNavigationView

class MainActivity : AppCompatActivity() {
    lateinit var buttonNavigationView: BottomNavigationView
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        init()
    }
    fun init(){
        bindView()
        var transaction = supportFragmentManager.beginTransaction()
        buttonNavigationView.setOnItemSelectedListener { item ->
            when(item.itemId) {
                R.id.item_1 -> {
                    var transaction = supportFragmentManager.beginTransaction()
                    transaction.replace(R.id.freame_layout,fragment1())
                    transaction.commit()
                    true
                }
                R.id.item_2 -> {
                    var transaction = supportFragmentManager.beginTransaction()
                    transaction.replace(R.id.freame_layout,fragment2())
                    transaction.commit()
                    true
                }
                else -> false
            }
        }
    }
    fun bindView(){
        buttonNavigationView = findViewById(R.id.bottom_navigation)
    }
}
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activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="10">

    <FrameLayout
        android:id="@+id/freame_layout"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="10"/>

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:menu="@menu/bottom_navigation_menu" />

</LinearLayout>

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create fragment1 and fragment2+

fragment1.xml:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".fragment1">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="fragment1"
        android:textSize="30sp"
        android:layout_gravity="center"
        android:gravity="center" />
</FrameLayout>

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fragment2.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".fragment2">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="fragment2"
        android:textSize="30sp"
        android:layout_gravity="center"
        android:gravity="center" />

</FrameLayout>

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fragment1.kt:

package com.example.test

import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
class fragment1 : Fragment() {
    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment1, container, false)
    }
}

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fragment2.kt:
package com.example.test

import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
class fragment2 : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment2, container, false)
    }
}