Develop Reference

Android Base activity for NavigatonDrawer

I was trying to implement Android NavigationDrawer menu with Base Activity to show navigation drawer for nested activities using Kotlin.
According to tutorial activity_base_drawer.xml contains content_layout, which contains FrameLayout and in this FrameLayout my activity should be rendered.
NavigationDrawer menu itself working fine but it doesn't render activity_main.xml to FrameLayout, so it is always shows content_layout.xml i.e. empty screen.
What I have missed? How could I render activity_main to FrameLayout?
activity_base_drawer.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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".activities.BaseDrawerActivity"
tools:openDrawer="start"
android:fitsSystemWindows="true">
<include layout="#layout/content_layout"
android:layout_height="match_parent"
android:layout_width="match_parent"/>
<com.google.android.material.navigation.NavigationView
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:layout_gravity="start"
android:id="#+id/nav_view"
app:headerLayout="#layout/main_drawer_header"
app:menu="#menu/main_drawer_menu"/>
</androidx.drawerlayout.widget.DrawerLayout>
content_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/appBarLayout"
app:layout_constraintTop_toTopOf="parent">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolBar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#color/app_main"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:titleTextColor="#color/app_main_text"/>
</com.google.android.material.appbar.AppBarLayout>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:id="#+id/activityContainer"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toTopOf="#+id/appBarLayout">
</FrameLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
BaseDrawerActivity.kt
open class BaseDrawerActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
lateinit var drawerLayout: DrawerLayout
override fun setContentView(view: View?) {
drawerLayout= layoutInflater.inflate(R.layout.activity_base_drawer, null) as DrawerLayout
val container = drawerLayout.findViewById<FrameLayout>(R.id.activityContainer)
container.addView(view)
super.setContentView(drawerLayout)
val toolbar: Toolbar =drawerLayout.findViewById(R.id.toolBar)
setSupportActionBar(toolbar)
val navigationView:NavigationView=drawerLayout.findViewById(R.id.nav_view)
navigationView.setNavigationItemSelectedListener(this)
val togle=ActionBarDrawerToggle(this#BaseDrawerActivity, drawerLayout, toolbar, R.string.menu_drawer_open, R.string.menu_drawer_close)
drawerLayout.addDrawerListener(togle)
togle.syncState()
}
}
MainActivity.kt
class MainActivity : BaseDrawerActivity() {
var activityMainBinding: ActivityMainBinding? =null
override fun onCreate(savedInstanceState: Bundle?) {
activityMainBinding=ActivityMainBinding.inflate(layoutInflater)
setContentView(activityMainBinding!!.root)
super.onCreate(savedInstanceState)
}
}

Fragment not showing properly

I am learning Kotlin, have done apps in Java before. I now have an activity with an Toolbar, NavigationView and a FragmentView. As I understand this: Fragment Tutorial, it is enough to state the Fragment in the xml file.
I have this activity_main.xml file:
<?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/navigation_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true">
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/main_app_bar_layout"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:theme="#style/AppTheme.AppBarOverlay"
app:layout_constraintTop_toTopOf="parent">
<androidx.appcompat.widget.Toolbar
android:id="#+id/main_toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#android:color/holo_blue_light"
app:popupTheme="#style/AppTheme.PopupOverlay" />
</com.google.android.material.appbar.AppBarLayout>
<com.google.android.material.navigation.NavigationView
android:id="#+id/main_navigation"
android:layout_marginTop="?attr/actionBarSize"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="#layout/navigation_header"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/main_app_bar_layout"
app:menu="#menu/navigation_menu" />
<androidx.fragment.app.FragmentContainerView
android:layout_marginTop="?attr/actionBarSize"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/main_container"
android:name="com.example.android.camerax.tflite.TestFragment"
tools:layout="#layout/fragment_test" />
</androidx.drawerlayout.widget.DrawerLayout>
This is the fragment_test.xml:
<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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.android.camerax.tflite.TestFragment">
<!-- TODO: Update blank fragment layout -->
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="#string/hello_blank_fragment"
android:textAlignment="center"
android:gravity="center"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
This is the Activity:
class CameraActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
private lateinit var fragment: CameraActivityFragment
private lateinit var navigationDrawer: DrawerLayout
private lateinit var toolbar: Toolbar
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_camera)
navigationDrawer = findViewById(R.id.navigation_container)
// Handle user consent update
toolbar = findViewById(R.id.main_toolbar)
setSupportActionBar(toolbar)
val toggle = ActionBarDrawerToggle(
this,
navigationDrawer,
toolbar,
R.string.navigation_drawer_open,
R.string.navigation_drawer_close
)
navigationDrawer.addDrawerListener(toggle)
toggle.syncState()
val navigationView: NavigationView = findViewById(R.id.main_navigation)
navigationView.setNavigationItemSelectedListener(this)
}
override fun onNavigationItemSelected(item: MenuItem): Boolean {
if (item.itemId == R.id.show_recordings) {
// Start ListView
}
navigationDrawer.closeDrawer(GravityCompat.START)
return true
}
}
and here is the TestFragment.kt:
class TestFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_test, container, false)
}
companion object {
// TODO: Rename and change types and number of parameters
#JvmStatic
fun newInstance(param1: String, param2: String) =
TestFragment().apply {
arguments = Bundle().apply {
}
}
}
}
I have tried to read the link above and also follow this: AndroidTrivia. No success and I really think this is quite basic and should work. When I run the debugger I can see that onCreateView is called in the Fragment, as it should be.
This is how it looks. Sometimes, the text blips on the screen. So seems like something is overwriting the fragment?
screenshot 1
screenshot 2
Edit
After updating the FragmentContainerView with elevation 9dp, the text is shown. But now the Toolbar is hidden, although there is a marginTop for the FragmentContainerView. Screenshot 3

There are two things I would like to suggest here.
First if possible get back to ConstraintLayout as in your last answer. It is not necessary for sure, but would recommend.
Second the blipping might be cause by the difference in elevation since the elevation of NavigationView is different.
So I suggest you add the following to your FragmentContainerView
<androidx.fragment.app.FragmentContainerView
android:layout_marginTop="?attr/actionBarSize"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/main_container"
android:elevation="9dp"
android:name="com.example.android.camerax.tflite.TestFragment"
tools:layout="#layout/fragment_test" />
9dp since most Android Views like BottomNav etc are upto 8dp
Also would recommend to modify your fragment_test as follows and add the following
<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:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white"
android:clickable="true"
android:focusable="true"
tools:context="com.example.android.camerax.tflite.TestFragment">
<!-- TODO: Update blank fragment layout -->
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="#string/hello_blank_fragment"
android:textAlignment="center"
android:gravity="center"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Getting DrawerLayout must be measured with MeasureSpec.EXACTLY when adding the drawer layout

I am trying to add drawerlayout in my fragment home. I am getting java.lang.IllegalArgumentException: DrawerLayout must be measured with MeasureSpec.EXACTLY. this error when I tried to attach drawer layout to my fragment.
I have root layout as constraint layout. Firstly I tried with root layout as drawerlayout still I wast getting this exception so I tried adding constraint layout to it but did not work.
It works when I give the hard coded value to height and width as 500dp.
But hard coded value cant be given as it will not be good practice for all devices size it will differ.
Below is my code
drawer layout
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:app="http://schemas.android.com/apk/res-auto"
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">
<androidx.drawerlayout.widget.DrawerLayout
android:id="#+id/drawer"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_width="match_parent"
android:layout_height="0dp"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
layout="#layout/fragment_home"
android:visibility="visible" />
<com.google.android.material.navigation.NavigationView
android:id="#+id/nav_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:layout_gravity="start">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include
android:id="#+id/nav_header"
layout="#layout/nav_header" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fadeScrollbars="true"
android:scrollbars="none">
<include
android:id="#+id/menuItems"
layout="#layout/layout_navigation_menu" />
</ScrollView>
</LinearLayout>
</com.google.android.material.navigation.NavigationView>
</androidx.drawerlayout.widget.DrawerLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
Home fragment layout
<?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:layout_width="match_parent"
android:layout_height="match_parent">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:fillViewport="true"
android:fitsSystemWindows="true">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/root"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<include android:id="#+id/app_bar"
layout="#layout/app_bar_main"/>
<RelativeLayout
android:id="#+id/relative_accept"
android:layout_width="match_parent"
android:layout_height="#dimen/margin_55"
android:orientation="horizontal"
android:background="#color/green_500"
app:layout_constraintTop_toBottomOf="#id/app_bar">
<androidx.appcompat.widget.AppCompatTextView
android:layout_width="wrap_content"
android:layout_alignParentStart="true"
android:layout_centerVertical="true"
android:textColor="#color/white"
android:layout_marginLeft="#dimen/margin_16"
android:layout_marginStart="#dimen/margin_16"
android:layout_marginRight="#dimen/margin_16"
android:layout_marginEnd="#dimen/margin_16"
android:text="#string/accepting_orders"
android:fontFamily="#font/roboto_regular"
android:textSize="#dimen/text_size_15"
android:layout_alignParentLeft="true"
android:layout_height="wrap_content" />
<Switch
android:id="#+id/switch1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:track="#drawable/switch_track_selector"
android:layout_centerVertical="true"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
tools:ignore="UseSwitchCompatOrMaterialXml" />
</RelativeLayout>
<FrameLayout
android:id="#+id/frameLayout_tab"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:clipToPadding="false"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/relative_accept">
<com.google.android.material.tabs.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="42dp"
android:layout_marginStart="#dimen/margin_16"
android:layout_marginLeft="#dimen/margin_16"
android:layout_marginTop="#dimen/margin_20"
android:layout_marginEnd="#dimen/margin_16"
android:layout_marginRight="#dimen/margin_16"
android:background="#drawable/grey_drawable"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:tabGravity="fill"
app:tabIndicatorHeight="0dp"
app:tabMode="fixed"
android:onClick="#{(v)->click.onClick(v)}"
app:tabBackground="#drawable/tab_selector"
app:tabSelectedTextColor="#color/white" />
</FrameLayout>
<androidx.viewpager.widget.ViewPager
android:id="#+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintTop_toBottomOf="#+id/frameLayout_tab" />
</androidx.constraintlayout.widget.ConstraintLayout>
</ScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>
Home fragment
class HomeFragment : BaseFragment() , View.OnClickListener{
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? = inflater.inflate(R.layout.drawer_layout_navigation_view, container, false)
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
init()
controlInit()
}
override fun init() {
val toggle = ActionBarDrawerToggle(
(activity as MainActivity),
drawer,
R.string.navigation_drawer_open,
R.string.navigation_drawer_close
)
drawer.addDrawerListener(toggle)
tabs.setupWithViewPager(view_pager)
bindViewPagerAdapter(view_pager, (activity as MainActivity))
bindViewPagerTabs(tabs, view_pager)
tabSettings()
}
private fun tabSettings() {
tabs.bringToFront()
view_pager.addOnPageChangeListener(object : ViewPager.OnPageChangeListener {
override fun onPageScrolled(
position: Int, positionOffset: Float, positionOffsetP: Int
) {
}
override fun onPageSelected(position: Int) {}
override fun onPageScrollStateChanged(i: Int) {}
})
}
private fun bindViewPagerAdapter(view: ViewPager?, mainActivity: MainActivity) {
val adapter = OrdersAdapter(view?.context!!, childFragmentManager)
view.adapter = adapter
}
private fun bindViewPagerTabs(view: TabLayout, pagerView: ViewPager?) {
view.setupWithViewPager(pagerView, true)
}
private fun controlInit() {
imageView_drawer.setOnClickListener(this)
}
#SuppressLint("WrongConstant")
override fun onClick(p0: View) {
when (p0.id) {
R.id.imageView_drawer -> {
drawer.openDrawer(Gravity.START)
}
}
}
companion object {
#JvmStatic
fun newInstance() =
HomeFragment().apply {}
}
}
Please help with this.Thank you....

Your layout actually worked just fine when I tested it so I am not sure if the issue lies with the layout. However your layout files are overly complex, you don't really need any of the nested layouts that you have and can achieve the same results without. ConstraintLayout was developed with the purpose of simplifying layout hierarchies so you should be able to just use that to organise your child views.
Also the NavigationView component is meant to be used to display a menu from a menu resource, not just to be used as a wrapper for your own. Either choose to display your own menu completely or use their implementation as intended. There is some nice documentation for this on the [Material Design website] here.
So may I suggest you try to cut down on nesting your layouts and then see whether this incidentally fixes your problem.
The hierarchy that you might want would probably look something like this:
drawer_layout.xml
<DrawerLayout>
<include layout="#layout/home" />
<NavigationView />
</DrawerLayout>
home.xml
<ScrollView>
<ConstraintLayout>
<include layout="#layout/app_bar_main"/>
<TextView />
<Switch />
<TabLayout />
<ViewPager />
</ConstraintLayout>
</ScrollView>

Kotlin update text of textview on different layout from activity

I have a navigation header as bellow
I want to update TextView in nav_header.xml from MainActivity.kt by Kotlin
I want to update text of TextView(id=drawer_user_name) from MainActivity.kt
main_activity.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:openDrawer="start">
<include
layout="#layout/content_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="45dp"
android:background="#android:drawable/screen_background_light_transparent"
tools:listitem="#layout/item_list" />
</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"
android:fitsSystemWindows="true"
app:headerLayout="#layout/nav_header"
app:menu="#menu/nav_menu" />
</androidx.drawerlayout.widget.DrawerLayout>
nav_header.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="200dp"
android:background="#4cAF50"
android:orientation="vertical"
android:layout_gravity="top"
android:paddingTop="35dp"
android:paddingLeft="15dp"
android:paddingBottom="15dp"
android:id="#+id/ddd">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#mipmap/ic_launcher"
android:id="#+id/imageView"
android:layout_marginBottom="15dp"/>
<TextView
android:id="#+id/drawer_user_name" //--> i want to update this TextView from MainActivity.kt
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="title"
android:textColor="#FFFFFF"
android:textStyle="bold" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="this our navigation drawer"
android:textColor="#FFFFFF" />
</LinearLayout>
content_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:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/colorPrimary"
android:background="?attr/colorPrimary"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:orientation="horizontal">
<TextView
style="#style/TextAppearance.AppCompat.Widget.ActionBar.Title"
android:id="#+id/home_page_username"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Chat"
android:textColor="#FFFFFF" />
</LinearLayout>
</androidx.appcompat.widget.Toolbar>
</com.google.android.material.appbar.AppBarLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="this is my content"/>
</LinearLayout>
</LinearLayout>
Please Help me,I really need a way to solve this problem
thank you
Babbab forces us to write stories here to allow us to post a question(It looks like your post is mostly code; please add some more details)
Edit
my MainActivity.kt
package com.example.myapplication
...
import android.view.LayoutInflater
import android.widget.LinearLayout
import kotlinx.android.synthetic.main.activity_main_page.*
import kotlinx.android.synthetic.main.nav_header.view.*
class MainPageActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener,CustomAdapter.OnItemClickListener {
lateinit var toolbar:androidx.appcompat.widget.Toolbar
lateinit var drawerLayout: DrawerLayout
lateinit var navView:NavigationView
private var data = arrayListOf<UserChanel>()
private lateinit var myadapter:CustomAdapter
private val gson = Gson()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
toolbar =findViewById(R.id.toolbar)
setSupportActionBar(toolbar)
drawerLayout = findViewById(R.id.drawer_layout)
navView = findViewById(R.id.nav_view)
val toggle = ActionBarDrawerToggle(this,drawerLayout,toolbar,0,0)
drawerLayout.addDrawerListener(toggle)
toggle.syncState()
navView.setNavigationItemSelectedListener(this)
// val userNameTextView = nav_view.findViewById<TextView>(R.id.drawer_user_name)
// userNameTextView.text = "SOME TEXT" // error
nav_view.drawer_user_name.text = "SOME TEXT" // Error
val recyclerview = findViewById<RecyclerView>(R.id.recycler_view)
// for insert line divider to recyclerview items
recyclerview.addItemDecoration(SimpleDividerItemDecoration(this)) // for insert line divider to recyclerview items
send_request()
val adapter = CustomAdapter(this,data,this)
recyclerview.layoutManager = LinearLayoutManager(this)
recyclerview.adapter = adapter
recyclerview.setHasFixedSize(true)
myadapter = adapter
}
override fun onNavigationItemSelected(item: MenuItem): Boolean {
when(item.itemId){
R.id.nav_profile->{
Toast.makeText(this,"profile clicked",Toast.LENGTH_SHORT).show()
}
R.id.nav_message->{
Toast.makeText(this,"message clicked",Toast.LENGTH_SHORT).show()
}
R.id.nav_frinds->{
Toast.makeText(this,"frinds clicked",Toast.LENGTH_SHORT).show()
}
R.id.nav_update->{
Toast.makeText(this,"update clicked",Toast.LENGTH_SHORT).show()
}
R.id.nav_logout->{
Toast.makeText(this,"logout clicked",Toast.LENGTH_SHORT).show()
}
}
drawerLayout.closeDrawer(GravityCompat.START)
return true
}
private fun send_request(){
...
}
override fun onItemClick(position: Int,adapter: CustomAdapter,v:View) {
...
}
}

You can find the target view from its parent in your activity like either of these ways:
nav_view.getHeaderView(0).findViewById<TextView>(R.id.drawer_user_name).text = "SOME TEXT"
or
import kotlinx.android.synthetic.main.nav_header.view.*
...
nav_view.getHeaderView(0).drawer_user_name.text = "SOME TEXT"
It's possible to access the header view using getheaderview(int index) according to the documentation. As you have one header view in the NavigationView, it is accessible by index 0.

Side Navigation Drawer Item click is not working although Navigation Drawer is visible and opens

I am trying to Implement Navigation drawer but when I run my application and click on items in the drawer it just closes the drawer without doing showing the toast. nothing is happening with my drawer when I click an Item to navigate i.e The content inside Navigation Drawer is not clickable i.e the menu.
Below are my codes for Navigation drawer:
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:openDrawer="start">
<include
layout="#layout/content_menu"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<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"
android:fitsSystemWindows="true"
app:headerLayout="#layout/nav_header"
app:menu="#menu/nav_menu"/>
<LinearLayout 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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".FirstMain"
android:orientation="vertical"
android:gravity="center">
<TextView
android:layout_width="300dp"
android:layout_height="wrap_content"
android:layout_marginBottom="40dp"
android:background="#color/back"
android:fontFamily="#font/berkshire_swash"
android:gravity="center"
android:text="#string/app_name"
android:textAlignment="center"
android:textColor="#color/txt"
android:textSize="50sp"
android:textStyle="bold" />
<Button
android:id="#+id/button"
android:layout_width="165dp"
android:layout_height="wrap_content"
android:layout_margin="30sp"
android:background="#color/back"
android:fontFamily="#font/berkshire_swash"
android:gravity="center_horizontal"
android:padding="10sp"
android:text="PLAY"
android:textColor="#color/txt"
android:textSize="35sp"
android:textStyle="bold" />
</LinearLayout>
</androidx.drawerlayout.widget.DrawerLayout>
nav_menu.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android">
<group android:checkableBehavior="single">
<item
android:id="#+id/nav_rule"
android:icon="#drawable/rules"
android:title="Rules" />
<item
android:id="#+id/nav_about"
android:icon="#drawable/about"
android:title="About"/>
</group>
</menu>
Content_menu.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:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.appbar.AppBarLayout
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light">
</androidx.appcompat.widget.Toolbar>
</com.google.android.material.appbar.AppBarLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#drawable/puzzle">
</LinearLayout>
</LinearLayout>
Main.kt
class FirstMain : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener{
lateinit var btn : Button
lateinit var toolbar: Toolbar
lateinit var drawerLayout: DrawerLayout
lateinit var navView: NavigationView
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_first_main)
btn = findViewById(R.id.button)
toolbar = findViewById(R.id.toolbar)
setSupportActionBar(toolbar)
drawerLayout = findViewById(R.id.drawer_layout)
navView = findViewById(R.id.nav_view)
val toggle = ActionBarDrawerToggle(
this, drawerLayout, toolbar, 0, 0
)
drawerLayout.addDrawerListener(toggle)
toggle.syncState()
btn.setOnClickListener {
val intent = Intent(this, MainActivity::class.java)
startActivity(intent)
}
navView.setNavigationItemSelectedListener(this)
}
override fun onNavigationItemSelected(p0: MenuItem): Boolean {
p0.isChecked = true
when (p0.itemId) {
R.id.nav_rule -> {
Toast.makeText(this, "Profile clicked", Toast.LENGTH_LONG).show()
}
R.id.nav_about -> {
Toast.makeText(this, "Messages clicked", Toast.LENGTH_LONG).show()
}
}
drawerLayout.closeDrawer(GravityCompat.START)
return true
}
}

Your code looks all good, weird it doesn't work but you can try and add
navView.bringToFront();
navView.setNavigationItemSelectedListener(this)