I have faced the problem that my application will keep stopping when clicking search page fragments. I do not understand why this problem will happen? I directly used my other success code in another fragment but in this fragment suddenly appear this problem. Can somebody help me? Thank you for your help!!
My problem error :
java.lang.NullPointerException: Attempt to invoke virtual method
'void androidx.recyclerview.widget.RecyclerView.setLayoutManager(androidx.recyclerview.widget.RecyclerView$LayoutManager)'
on a null object reference at com.example.assignment_mad.Search_Page_Fragment.onViewCreated(Search_Page_Fragment.kt:153)
My main frgment ( Search_Page_Fragment ) :
package com.example.assignment_mad
import android.content.Intent
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Toast
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import kotlinx.android.synthetic.main.fragment_notification_.*
class Search_Page_Fragment : Fragment() {
private lateinit var newRecyclerView: RecyclerView
private lateinit var newArrayList: ArrayList<Company_Search>
private lateinit var tempArrayList: ArrayList<Company_Search>
lateinit var imageId:Array<Int>
lateinit var job_name:Array<String>
lateinit var saveicon:Array<Int>
lateinit var company_name:Array<String>
lateinit var place:Array<String>
lateinit var salary:Array<String>
lateinit var news:Array<String>
private var layoutManager: RecyclerView.LayoutManager? = null
private var adapter: RecyclerView.Adapter<Search_Page_Adapter.MyViewHolder>? = null
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
var views =inflater.inflate(R.layout.fragment_search__page_, container, false)
newRecyclerView=views.findViewById(R.id.recyclerView_Search)
// Inflate the layout for this fragment
return views
}
override fun onViewCreated(itemView: View, savedInstanceState: Bundle?) {
imageId= arrayOf(
R.drawable.company_logo_1,
R.drawable.company_logo_2,
R.drawable.company_logo_3,
R.drawable.company_logo_4,
R.drawable.company_logo_5,
R.drawable.company_logo_6,
R.drawable.company_logo_7,
R.drawable.company_logo_8,
R.drawable.company_logo_9,
R.drawable.company_logo_10
)
job_name= arrayOf(
"Engineer",
"Computer",
"Coder",
"Teacher",
"Engineer",
"Engineer",
"Engineer",
"Engineer",
"Engineer",
"Engineer"
)
saveicon= arrayOf(
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24
)
company_name= arrayOf(
"Phonix Sdn Bhd",
"Computer Sdn Bhd",
"Coder",
"Teacher",
"Engineer",
"Engineer",
"Engineer",
"Engineer",
"Engineer",
"Engineer"
)
place= arrayOf(
"Kuala Lumpur",
"Kuala Lumpur",
"Selangor",
"Rimbunan",
"Kuala Lumpur",
"Kuala Lumpur",
"Kuala Lumpur",
"Kuala Lumpur",
"Kuala Lumpur",
"Kuala Lumpur"
)
salary= arrayOf(
"RM3000",
"RM4000",
"RM3500",
"RM2000",
"RM1000",
"RM3000",
"RM3000",
"RM3000",
"RM3000",
"RM3000",
)
news= arrayOf(
getString(R.string.news_a),
getString(R.string.news_b),
getString(R.string.news_c),
getString(R.string.news_d),
getString(R.string.news_e),
getString(R.string.news_f),
getString(R.string.news_g),
getString(R.string.news_h),
getString(R.string.news_i),
getString(R.string.news_j)
)
newArrayList= arrayListOf<Company_Search>()
tempArrayList= arrayListOf<Company_Search>()
getUserdata()
super.onViewCreated(itemView, savedInstanceState)
newRecyclerView.apply {
layoutManager= LinearLayoutManager(activity)
newRecyclerView.setHasFixedSize(true)
}
recyclerView.apply {
// set a LinearLayoutManager to handle Android
// RecyclerView behavior
layoutManager= LinearLayoutManager(activity)
// set the custom adapter to the RecyclerView
adapter = Search_Page_Adapter(newArrayList)
}
}
private fun getUserdata() {
for (i in imageId.indices){
val companySearch=Company_Search(imageId[i],job_name[i],saveicon[i],company_name[i],place[i],salary[i])
newArrayList.add(companySearch)
}
// tempArrayList.addAll(newArrayList)
//
// val adapter = Notification_Fragment(tempArrayList)
var adapter=Search_Page_Adapter(newArrayList)
newRecyclerView.adapter=adapter
adapter.setOnItemClickListener(object :Search_Page_Adapter.onItemClickListener{
override fun onItemClick(position: Int) {
Toast.makeText(context,"You clicked in item no . $position",Toast.LENGTH_SHORT).show()
val intent= Intent(context,Search_Page_Detail::class.java)
intent.putExtra("name",newArrayList[position].job_name)
intent.putExtra("imageId",newArrayList[position].titleImage)
intent.putExtra("news",news[position])
startActivity(intent)
}
})
}
}
The page adapter :
package com.example.assignment_mad
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.google.android.material.imageview.ShapeableImageView
class Search_Page_Adapter(private val companysList:ArrayList<Company_Search>):RecyclerView.Adapter<Search_Page_Adapter.MyViewHolder>() {
private var mListener:onItemClickListener?=null
interface onItemClickListener{
fun onItemClick(position: Int)
}
fun setOnItemClickListener(listener: onItemClickListener){
mListener=listener
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
val itemView=LayoutInflater.from(parent.context).inflate(R.layout.list_item_search,parent,false)
return MyViewHolder(itemView,mListener)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val currentItem=companysList[position]
holder.titleImage.setImageResource(currentItem.titleImage)
holder.job_name.text=currentItem.job_name
holder.save_icon.setImageResource(currentItem.save_icon)
holder.company_name.text=currentItem.company_name
holder.place.text=currentItem.place
holder.salary.text=currentItem.salary
}
override fun getItemCount(): Int {
return companysList.size
}
//to insert the post detail
class MyViewHolder(itemView: View,listener: onItemClickListener?):RecyclerView.ViewHolder(itemView){
val titleImage:ShapeableImageView=itemView.findViewById(R.id.title_image2)
val job_name:TextView=itemView.findViewById(R.id.job_name)
val save_icon:ShapeableImageView=itemView.findViewById(R.id.save_icon)
val company_name:TextView=itemView.findViewById(R.id.company_name)
val place:TextView=itemView.findViewById(R.id.detail_place)
val salary:TextView=itemView.findViewById(R.id.detail_salary)
init {
itemView.setOnClickListener{
listener?.onItemClick(adapterPosition)
}
}
}
}
The xml file for search_fragment :
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
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="@color/white"
tools:context=".Search_Page_Fragment">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="@ id/search_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Search Job"
android:inputType="text"
android:minHeight="48dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
<TextView
android:id="@ id/place_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="@color/black"
android:text="Area, City or Town"
android:textSize="16sp"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintTop_toBottomOf="@ id/search_bar"
app:layout_constraintStart_toStartOf="parent"/>
<Spinner
android:id="@ id/spinner_job"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:minWidth="200dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@ id/place_name" />
<TextView
android:id="@ id/job_specialize"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="@color/black"
android:text="Job Specialize"
android:textSize="16sp"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintTop_toBottomOf="@ id/search_bar"
app:layout_constraintEnd_toEndOf="parent" />
<Spinner
android:id="@ id/spinner_place"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:minWidth="200dp"
app:layout_constraintTop_toBottomOf="@ id/job_specialize"
app:layout_constraintEnd_toEndOf="parent"
/>
<androidx.recyclerview.widget.RecyclerView
android:id="@ id/recyclerView_Search"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="108dp"
app:layout_constraintTop_toBottomOf="@ id/spinner_job"
tools:layout_editor_absoluteX="-16dp"
tools:listitem="@layout/list_item_search" />
</androidx.constraintlayout.widget.ConstraintLayout>
</FrameLayout>The list_item_search_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="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_margin="8dp">
<com.google.android.material.imageview.ShapeableImageView
android:layout_width="80dp"
android:layout_height="80dp"
android:id="@ id/title_image2"
android:scaleType="centerCrop"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:shapeAppearanceOverlay="@style/RoundCorner"
android:src="@drawable/company_logo_1"/>
<TextView
android:id="@ id/job_name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:textColor="@color/blue"
android:text="Gradute Engineer"
android:textSize="20sp"
android:textStyle="bold"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@ id/title_image2"/>
<ImageView
android:layout_width="40dp"
android:layout_height="40dp"
android:id="@ id/save_icon"
android:scaleType="centerCrop"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@ id/title_image2"
android:layout_marginEnd="32dp"
app:shapeAppearanceOverlay="@style/RoundCorner"
android:src="@drawable/ic_baseline_bookmark_added_24"/>
<TextView
android:id="@ id/company_name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:textColor="@color/black"
android:text="Neric Compat"
android:textSize="18sp"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@ id/job_name"/>
<TextView
android:id="@ id/detail_place"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:textColor="@color/black"
android:text="Petaling Jaya"
android:textSize="16sp"
android:textStyle="bold"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@ id/company_name"/>
<TextView
android:id="@ id/detail_salary"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:textColor="@color/black"
android:text="MYR 3,700 - 4,300 /Month"
android:textSize="16sp"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@ id/detail_place"/>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_margin="8dp"
style="bold"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@ id/detail_salary"
android:background="@color/underline"/>
</androidx.constraintlayout.widget.ConstraintLayout>CodePudding user response：
Your NullPointerException indicates that when this line of code is reached...
layoutManager= LinearLayoutManager(activity)
...that your newRecyclerView is null. Are you sure that you have the right resource ID here when you attempt to set it?
newRecyclerView=views.findViewById(R.id.recyclerView_Search)
Try using the debugger and set a breakpoint on these two lines to confirm is newRecyclerView is indeed null.
CodePudding user response：
You must assign the RecyclerView a LayoutManager. Since you have both of them, place this line as the last statement of recyclerView.apply { … } block(s):
setLayoutManager(layoutManager)
// ↑↑↑↑↑↑↑↑↑↑↑↑↑
// Your LayoutManager