After second click on Fragment, recycler view disappears - kotlin

Question

When I Click on Home navigation fragment(there is recyclerview) recycler view disappears with error message: E/RecyclerView: No adapter attached; skipping layout
when the app launchs it appears but when i move to another fragment and return again to home fragment, recycler view just disappears. even If I dont move on another fragment and click on home fragment, it still disappears.
What could be the problem and what can I do to fix it?
My codes:
fragment_home.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="1dp"
android:layout_marginTop="1dp"
android:layout_marginEnd="1dp"
android:layout_marginBottom="1dp"
android:paddingBottom="65dp"
app:reverseLayout="false" />
</LinearLayout>
Posts.kt
data class Posts(
var id: Int,
var imageUrl: String,
var title: String,)
MainActivity.kt
class MainActivity : AppCompatActivity() {
private lateinit var recyclerView: RecyclerView
private lateinit var recyclerViewPersonAdapter: RecyclerViewPersonAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val navView = findViewById<BottomNavigationView>(R.id.bottomNavMenu)
val controller = findNavController(R.id.nav_host_fragment)
val appBarConfiguration = AppBarConfiguration(
setOf(
R.id.homeFragment,
R.id.addFragment,
R.id.userFragment
)
)
setupActionBarWithNavController(controller, appBarConfiguration)
navView.setupWithNavController(controller)
recyclerView = findViewById(R.id.recyclerView)
recyclerView.layoutManager = LinearLayoutManager(this)
recyclerView.adapter = RecyclerViewPersonAdapter(getData())
}
private fun getData() : List<Posts>{
val list = ArrayList<Posts>()
list.add(
Posts(
1,
"https://www.myanbiz-consulting.com/wp-content/uploads/2019/04/4214892-news-images.jpg",
"Best news in the world\nfor you"
)
)
list.add(
Posts(
2,
"https://www.myanbiz-consulting.com/wp-content/uploads/2019/04/4214892-news-images.jpg",
"very very gooood\nnews for you"
)
)
list.add(
Posts(
3,
"https://www.myanbiz-consulting.com/wp-content/uploads/2019/04/4214892-news-images.jpg",
"very very gooood\nnews for you"
)
)
list.add(
Posts(
4,
"https://www.myanbiz-consulting.com/wp-content/uploads/2019/04/4214892-news-images.jpg",
"very very gooood\nnews for you"
)
)
return list
}
}
RecyclerViewPersonAdapter.kt
class RecyclerViewPersonAdapter(private val list: List<Posts>) : RecyclerView.Adapter<RecyclerViewPersonAdapter.PersonViewHolder>() {
class PersonViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView){
val imageView: ImageView
val textView: TextView
init {
imageView = itemView.findViewById(R.id.imageView)
textView = itemView.findViewById(R.id.textView)
}
fun setData(posts: Posts){
Glide.with(itemView.context)
.load(posts.imageUrl)
.into(imageView)
textView.text = posts.title
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PersonViewHolder {
val itemView = LayoutInflater.from(parent.context).inflate(R.layout.news_post, parent, false)
return PersonViewHolder(itemView)
}
override fun onBindViewHolder(holder: PersonViewHolder, position: Int) {
val posts = list[position]
holder.setData(posts)
}
override fun getItemCount(): Int {
return list.size
}
}
news_post.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="400dp"
android:layout_height="100dp"
android:background="#color/teal_200"
android:layout_marginTop="15dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:orientation="horizontal">
<ImageView
android:id="#+id/imageView"
android:layout_width="100dp"
android:layout_height="100dp"
android:scaleType="centerCrop"
android:src="#drawable/img" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="22dp"
android:orientation="vertical">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:lineSpacingExtra="8sp"
android:text="Best news in the world\nfor you"
android:textColor="#color/black"
android:textSize="16sp"
android:textStyle="bold" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="12dp"
android:orientation="horizontal">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:orientation="horizontal">
<ImageView
android:layout_width="14dp"
android:layout_height="14dp"
android:layout_gravity="center"
android:src="#drawable/ic_baseline_thumb_up_alt_24" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="8dp"
android:lineSpacingExtra="7sp"
android:text="2,687"
android:textColor="#333333"
android:textSize="13sp" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="22dp"
android:layout_weight="1"
android:orientation="horizontal">
<ImageView
android:layout_width="14dp"
android:layout_height="14dp"
android:layout_gravity="center"
android:src="#drawable/ic_baseline_remove_red_eye_24" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="8dp"
android:lineSpacingExtra="7sp"
android:text="32,577"
android:textColor="#333333"
android:textSize="13sp" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>

Answer 1

Your RecyclerView is in fragment_home.xml.
But you declare it in MainActivity.
Just do that in your HomeFragment instead of MainActivity.
class HomeFragment : Fragment() {
private lateinit var recyclerView: RecyclerView
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
recyclerView = view.findViewById(R.id.recyclerView)
recyclerView.layoutManager = LinearLayoutManager(requireContext())
recyclerView.adapter = RecyclerViewPersonAdapter(getData())
...