How do I make Activity to work inside fragment?

Question

When I select the chillzone fragment from the Navigation Drawer I am able to switch the fragments but When I try to select something from the BottomNavigationView nothing happens.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context=".ui.MainActivity"
    tools:openDrawer="end">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <androidx.appcompat.widget.Toolbar
            android:id="@+id/main_toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@color/colorPrimary"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

        <FrameLayout
            android:id="@+id/fragment_container"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

    </LinearLayout>

    <com.google.android.material.navigation.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

</androidx.drawerlayout.widget.DrawerLayout>

chillzone_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context=".ui.chillzone.ChillZoneActivity"
    tools:openDrawer="start">

    <TextView
        android:id="@+id/message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="172dp"
        android:layout_marginLeft="172dp"
        android:layout_marginTop="356dp"
        android:text="@string/chillzone"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_nav_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="0dp"
        android:background="?android:attr/windowBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/bottom_nav_menu" />

</androidx.constraintlayout.widget.ConstraintLayout>

ChillZoneActivity

package com.rishabhdeepsingh.metaapp.ui.chillzone

import android.os.Bundle
import android.util.Log
import com.google.android.material.bottomnavigation.BottomNavigationView
import androidx.appcompat.app.AppCompatActivity
import android.widget.TextView
import android.widget.Toast
import com.rishabhdeepsingh.metaapp.R

class ChillZoneActivity : AppCompatActivity() {

    private lateinit var bottomNavigationView: BottomNavigationView
    private lateinit var textMessage: TextView
    private val onNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item ->
        println("~~~~~~~~~~~~~~~~~~~~~~~~")
        when (item.itemId) {
            R.id.navigation_home -> {
                textMessage.setText(R.string.title_home)
                Toast.makeText(this, "Home", Toast.LENGTH_LONG).show()
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_dashboard -> {
                textMessage.setText(R.string.title_dashboard)
                Toast.makeText(this, "Dashboard", Toast.LENGTH_LONG).show()
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_notifications -> {
                textMessage.setText(R.string.title_notifications)
                Toast.makeText(this, "Notifications", Toast.LENGTH_LONG).show()
                return@OnNavigationItemSelectedListener true
            }
        }
        false
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        bottomNavigationView = findViewById(R.id.bottom_nav_view)
        println("~~~~~~~~~~~~~~!!!!!!!!!!!!!!!!!!!!!~~~~~~~~~~")
        Toast.makeText(this, "Hello", Toast.LENGTH_LONG).show()
        textMessage = findViewById(R.id.message)
        bottomNavigationView.setOnNavigationItemSelectedListener(onNavigationItemSelectedListener)
    }
}

ChillZoneFragment.kt

package com.rishabhdeepsingh.metaapp.ui.chillzone

import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import com.rishabhdeepsingh.metaapp.R

class ChillZoneFragment : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.chillzone_fragment, container, false)
    }
}

MainActivity.kt

package com.rishabhdeepsingh.metaapp.ui

import android.os.Bundle
import androidx.core.view.GravityCompat
import androidx.appcompat.app.ActionBarDrawerToggle
import android.view.MenuItem
import android.widget.Toast
import androidx.drawerlayout.widget.DrawerLayout
import com.google.android.material.navigation.NavigationView
import androidx.appcompat.app.AppCompatActivity
import androidx.appcompat.widget.Toolbar
import com.rishabhdeepsingh.metaapp.R
import com.rishabhdeepsingh.metaapp.ui.chillzone.ChillZoneFragment


class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {

    private lateinit var drawerLayout: DrawerLayout

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

        val toolbar: Toolbar = findViewById(R.id.main_toolbar)
        setSupportActionBar(toolbar)

        val navView: NavigationView = findViewById(R.id.nav_view)
        navView.setNavigationItemSelectedListener(this)

        drawerLayout = findViewById(R.id.drawer_layout)
        val toggle = ActionBarDrawerToggle(
            this, drawerLayout, toolbar,
            R.string.navigation_drawer_open,
            R.string.navigation_drawer_close
        )
        drawerLayout.addDrawerListener(toggle)
        toggle.syncState()

        if (savedInstanceState == null) {
            supportFragmentManager
                .beginTransaction()
                .replace(R.id.fragment_container, HomeFragment())
                .commit()
            navView.setCheckedItem(R.id.home)
        }
    }

    override fun onBackPressed() {
        if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
            drawerLayout.closeDrawer(GravityCompat.START)
        } else {
            super.onBackPressed()
        }
    }

    override fun onNavigationItemSelected(item: MenuItem): Boolean {
        // Handle navigation view item clicks here.
        when (item.itemId) {
            R.id.nav_home -> {
                // Handle the camera action
                supportFragmentManager
                    .beginTransaction()
                    .replace(R.id.fragment_container, HomeFragment())
                    .commit()
            }
            R.id.nav_chillzone -> {
                supportFragmentManager
                    .beginTransaction()
                    .replace(R.id.fragment_container, ChillZoneFragment())
                    .commit()
            }
            R.id.nav_slideshow -> {

            }
            R.id.nav_tools -> {

            }
            R.id.nav_share -> {
                Toast.makeText(this, "Share", Toast.LENGTH_SHORT).show()
            }
            R.id.nav_send -> {

            }
        }
        drawerLayout.closeDrawer(GravityCompat.START)
        return true
    }
}

I expected that the Toast message should appear corresponding to the BottomNavigationView button I select.

Answer 1

Android Fragment is the part of activity, it is also known as sub-activity. There can be more than one fragment in an activity. Fragments represent multiple screen inside one activity.

Android fragment lifecycle is affected by activity lifecycle because fragments are included in activity.

Each fragment has its own life cycle methods that is affected by activity life cycle because fragments are embedded in activity.

The FragmentManager class is responsible to make interaction between fragment objects.

You can't add activity inside fragment.

I hope It helps you!

Answer 2

Your BottomNavigationView related code is in the ChillZoneActivity. It needs to be in the ChillZoneFragment.

class ChillZoneFragment : Fragment() {

    private lateinit var bottomNavigationView: BottomNavigationView
    private lateinit var textMessage: TextView
    private val onNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item ->
        println("~~~~~~~~~~~~~~~~~~~~~~~~")
        when (item.itemId) {
            R.id.navigation_home -> {
                textMessage.setText(R.string.title_home)
                Toast.makeText(this, "Home", Toast.LENGTH_LONG).show()
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_dashboard -> {
                textMessage.setText(R.string.title_dashboard)
                Toast.makeText(this, "Dashboard", Toast.LENGTH_LONG).show()
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_notifications -> {
                textMessage.setText(R.string.title_notifications)
                Toast.makeText(this, "Notifications", Toast.LENGTH_LONG).show()
                return@OnNavigationItemSelectedListener true
            }
        }
        false
    }

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val view = inflater.inflate(R.layout.chillzone_fragment, container, false)
        bottomNavigationView = view.findViewById(R.id.bottom_nav_view)
        textMessage = view.findViewById(R.id.message)
        bottomNavigationView.setOnNavigationItemSelectedListener(onNavigationItemSelectedListener)
        return view
    }
}

P.S - You can't make an activity 'work' inside a fragment. That's just not how it works. Fragments are contained in the activity, never the other way around.

A Fragment represents a behavior or a portion of user interface in a FragmentActivity. You can combine multiple fragments in a single activity to build a multi-pane UI and reuse a fragment in multiple activities. You can think of a fragment as a modular section of an activity, which has its own lifecycle, receives its own input events, and which you can add or remove while the activity is running (sort of like a "sub activity" that you can reuse in different activities).

A fragment must always be hosted in an activity and the fragment's lifecycle is directly affected by the host activity's lifecycle.

Refer to the official documentation for further details.

Answer 3

Seems like bottom navigation listener is not being set properly try switching this:

bottomNavigationView.setOnNavigationItemSelectedListener(onNavigationItemSelectedListener)

to:

bottomNavigationView.setOnNavigationItemSelectedListener(this)