Recyclerview notifyItemInserted 在空指针异常中使我的应用程序崩溃

Question

我正在尝试通过单击按钮将一个元素添加到我的回收站视图中，但每次都以空指针异常结束时，你能帮我吗？

Liste_produits.java :

package com.example.gestiondestocktubconcept.vue;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.FileProvider;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Adapter;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import com.example.gestiondestocktubconcept.R;
import com.example.gestiondestocktubconcept.modele.Profil;

import org.w3c.dom.Text;

import java.io.File;
import java.io.FileOutputStream;
import java.text.BreakIterator;
import java.util.ArrayList;
import java.util.List;

public class liste_produits extends AppCompatActivity {



  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_liste_produits);

      // set up the RecyclerView
      RecyclerView recyclerView = findViewById(R.id.rv_produits);

      List<Profil> listeProduit = new ArrayList<>();

      LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
      recyclerView.setLayoutManager(linearLayoutManager);
      // initialisation de l'adapter
      MyRecyclerViewAdapter adapter = new MyRecyclerViewAdapter(getListeProduit());
      recyclerView.setAdapter(adapter);




      //this.getListeProduit().add(new Profil("voiture","RF745963-65","twingo",3000.,1,"c une joli voiture"));

  }



  //addItem(listeProduit,"voiture","RF745963-65","twingo",3000.,1,"c une joli voiture");
  List<Profil> listeProduit = new ArrayList<>();

  static List<Profil> getListeProduit() {
      List<Profil> listeProduit = new ArrayList<>();
      //Liste de nos produits
      //  ajout_produits(listeProduit,txt_categorie,txt_reference,txt_nom,Double.parseDouble(txt_prix),Integer.parseInt(txt_quantite),txt_description);
      listeProduit.add(new Profil("Voiture","A1232","Lamborghini Uracan",230000.00,5,"ceci est une description"));

      return listeProduit;
  }

  public static void ajout_produits(List<Profil> listeProduit, String categorie, String reference, String nom, Double prix, int quantite, String descritpion) {
      listeProduit.add(new Profil(categorie, reference, nom, prix, quantite, descritpion));
      //adapter.notifyItemInserted(adapter.getItemCount()-1);
  }




  /* ++propriétées++ */
  private ListView listView;
  MyRecyclerViewAdapter adapter;
  Integer nbr_click = 0;
  /* --propriétées-- */


  public void onClickData(View view) {

      EditText txt_input_categorie = (EditText) findViewById(R.id.txt_input_categorie);
      EditText txt_input_reference = (EditText) findViewById(R.id.txt_input_reference);
      EditText txt_input_nom = (EditText) findViewById(R.id.txt_input_nom);
      EditText txt_input_prix = (EditText) findViewById(R.id.txt_input_prix);
      EditText txt_input_quantite = (EditText) findViewById(R.id.txt_input_quantite);
      EditText txt_input_description = (EditText) findViewById(R.id.txt_input_description);
      Button btn_ajouter = (Button) findViewById(R.id.btn_ajouter);


      if (txt_input_categorie != null && txt_input_reference != null && txt_input_nom != null && txt_input_prix != null && txt_input_quantite != null && txt_input_description != null) {
          String value_description = txt_input_description.getText().toString();
          Integer value_quantite = (Integer.valueOf(txt_input_quantite.getText().toString()));
          Double value_prix = Double.parseDouble(txt_input_prix.getText().toString());
          String value_nom = txt_input_nom.getText().toString();
          String value_reference = txt_input_reference.getText().toString();
          String value_categorie = txt_input_categorie.getText().toString();

          Toast.makeText(getApplicationContext(), "ALED CA MARCHE PAS", Toast.LENGTH_LONG).show();
          listeProduit.add(new Profil("voiture", "RF745963-65", "twingo", 3000., 1, "c une joli voiture"));
          //listeProduit.add(new Profil(value_categorie, value_reference, value_nom, value_prix, value_quantite, value_description));
         adapter.notifyItemInserted(1);


      } else {
          Toast.makeText(getApplicationContext(), "Veuillez entrer des données", Toast.LENGTH_LONG).show();
      }
  }



      public void export (View view){


          /*  ++Creation des données++  */

          StringBuilder data = new StringBuilder();

          data.append("Catégorie,Référence,Nom,Prix,Quantités,Description");
          for (int i = 0; i < 6; i++) {
              data.append("\n" + "test");
          }

          /*  --Creation des données--  */


          try {
              /*  ++Sauvegarde des données dans l'appareil++ */

              FileOutputStream out = openFileOutput("data.csv", Context.MODE_PRIVATE);
              out.write((data.toString()).getBytes());
              out.close();

              /*  --Sauvegarde des données dans l'appareil-- */


              /*  ++Export des données++  */

              Context context = getApplicationContext();
              File filelocation = new File(getFilesDir(), "data.csv");
              Uri path = FileProvider.getUriForFile(context, "com.example.gestiondestocktubconcept.FileProvider", filelocation);
              Intent fileIntent = new Intent(Intent.ACTION_SEND);
              fileIntent.setType("text/csv");
              fileIntent.putExtra(Intent.EXTRA_SUBJECT, "Data");
              fileIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
              fileIntent.putExtra(Intent.EXTRA_STREAM, path);
              startActivity(Intent.createChooser(fileIntent, "Send mail"));

              /*  --Export des données--  */
          } catch (Exception e) {
              e.printStackTrace();
          }


      }


  }

MyRecyclerViewAdapter.java :

package com.example.gestiondestocktubconcept.vue;

import android.text.Layout;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.example.gestiondestocktubconcept.R;
import com.example.gestiondestocktubconcept.modele.Profil;

import java.util.List;


public class MyRecyclerViewAdapter extends RecyclerView.Adapter {

   private AdapterView.OnItemClickListener onItemClickListener;

   List<Profil> liste_produit;

//Constructeur de la liste des produits
   public MyRecyclerViewAdapter(List<Profil> liste_produit) {
       this.liste_produit = liste_produit;
   }

   @NonNull
   @Override
   public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
       View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_row,parent,false);
       return new RowViewHolder(itemView);
   }
// Lie les élements avec la vue
   @Override
   public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
       RowViewHolder rowViewHolder = (RowViewHolder) holder;

       int rowPos = rowViewHolder.getBindingAdapterPosition();
       ;

       if (rowPos == 0) {
           //Cellules de l'entête
           // permet de mettre un background a la cellule : rowViewHolder.txt_categorie.setBackgroundResource();
          rowViewHolder.txt_categorie.setText("Catégorie");
          rowViewHolder.txt_reference.setText("Reference");
          rowViewHolder.txt_nom.setText("Nom");
          rowViewHolder.txt_prix.setText("Prix");
          rowViewHolder.txt_quantite.setText("Quantité");
          rowViewHolder.txt_description.setText("Description");
       } else{
           Profil profil = liste_produit.get(rowPos-1);

           //Contenues des cellules
           rowViewHolder.txt_categorie.setText(profil.getCategorie()+"");
           rowViewHolder.txt_reference.setText(profil.getReference()+"");
           rowViewHolder.txt_nom .setText(profil.getNom()+"");
           rowViewHolder.txt_prix.setText(profil.getPrixUnite()+"");
           rowViewHolder.txt_quantite.setText(profil.getQuantite()+"");
           rowViewHolder.txt_description.setText(profil.getDescription()+"");



       }

   }

   @Override
   public int getItemCount() {
       return liste_produit.size()+1;
   }




   public class RowViewHolder extends RecyclerView.ViewHolder {
       protected TextView txt_categorie;
       protected TextView txt_reference;
       protected TextView txt_nom;
       protected TextView txt_prix;
       protected TextView txt_quantite;
       protected TextView txt_description;

       public RowViewHolder(View itemView) {
           super(itemView);

           txt_categorie = itemView.findViewById(R.id.tv_categorie_produit);
           txt_reference = itemView.findViewById(R.id.tv_reference_produit);
           txt_nom = itemView.findViewById(R.id.tv_nom_produit);
           txt_prix = itemView.findViewById(R.id.tv_prix_produit);
           txt_quantite = itemView.findViewById(R.id.tv_quantite_produit);
           txt_description = itemView.findViewById(R.id.tv_description_produit);
       }
   }

   String getItem(int id) {
       return String.valueOf(liste_produit.get(id));
   }



}

activity_liste_produits.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/constraint_layout"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".vue.liste_produits">

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

       <LinearLayout
           android:layout_width="match_parent"
           android:layout_height="match_parent"
           android:layout_gravity="center|center_horizontal|center_vertical"
           android:layout_weight="1"
           android:gravity="center|center_horizontal|center_vertical"
           android:orientation="horizontal">

           <LinearLayout
               android:layout_width="match_parent"
               android:layout_height="match_parent"
               android:layout_weight="1"
               android:orientation="vertical">

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <TextView
                       android:id="@+id/txt_categorie"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center|center_horizontal|center_vertical"
                       android:gravity="center|center_horizontal|center_vertical"
                       android:text="Catégorie : " />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <TextView
                       android:id="@+id/txt_reference"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center|center_horizontal|center_vertical"
                       android:gravity="center|center_horizontal|center_vertical"
                       android:text="Réference : " />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <TextView
                       android:id="@+id/txt_nom"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center|center_horizontal|center_vertical"
                       android:gravity="center|center_horizontal|center_vertical"
                       android:text="Nom" />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <TextView
                       android:id="@+id/txt_prix"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center|center_horizontal|center_vertical"
                       android:gravity="center|center_horizontal|center_vertical"
                       android:text="Prix : " />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <TextView
                       android:id="@+id/txt_quantite"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center|center_horizontal|center_vertical"
                       android:gravity="center|center_horizontal|center_vertical"
                       android:text="Quantités : " />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <TextView
                       android:id="@+id/txt_description"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center|center_horizontal|center_vertical"
                       android:gravity="center|center_horizontal|center_vertical"
                       android:text="Description : " />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical" >

                   <Button
                       android:id="@+id/button"
                       android:layout_width="match_parent"
                       android:layout_height="wrap_content"
                       android:onClick="onClickData"
                       android:text="Ajouter Ligne" />
               </LinearLayout>
           </LinearLayout>

           <LinearLayout
               android:layout_width="match_parent"
               android:layout_height="match_parent"
               android:layout_weight="1"
               android:orientation="vertical">


               <LinearLayout


                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical"

                   >

                   <EditText
                       android:id="@+id/txt_input_categorie"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center_horizontal|center_vertical"
                       android:gravity="center|center_vertical"
                       android:inputType="text"
                       android:text="test" />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <EditText
                       android:id="@+id/txt_input_reference"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center_horizontal|center_vertical"
                       android:gravity="center|center_vertical"
                       android:inputType="text"
                       android:text="test" />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <EditText
                       android:id="@+id/txt_input_nom"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center_horizontal|center_vertical"
                       android:gravity="center|center_vertical"
                       android:inputType="text"
                       android:text="test" />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <EditText
                       android:id="@+id/txt_input_prix"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center_horizontal|center_vertical"
                       android:gravity="center|center_vertical"
                       android:inputType="text"
                       android:text="12.12" />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <EditText
                       android:id="@+id/txt_input_quantite"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center_horizontal|center_vertical"
                       android:gravity="center|center_vertical"
                       android:inputType="text"
                       android:text="2" />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <EditText
                       android:id="@+id/txt_input_description"
                       android:layout_width="match_parent"
                       android:layout_height="match_parent"
                       android:layout_gravity="center_horizontal|center_vertical"
                       android:gravity="center|center_vertical"
                       android:inputType="text"
                       android:text="test" />
               </LinearLayout>

               <LinearLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:layout_weight="1"
                   android:orientation="vertical">

                   <Button
                       android:id="@+id/btn_ajouter"
                       android:layout_width="match_parent"
                       android:layout_height="wrap_content"
                       android:onClick="export"
                       android:text="Exporter" />
               </LinearLayout>
           </LinearLayout>
       </LinearLayout>

       <LinearLayout
           android:layout_width="match_parent"
           android:layout_height="match_parent"
           android:layout_weight="1"
           android:orientation="vertical">

           <androidx.recyclerview.widget.RecyclerView

               android:id="@+id/rv_produits"
               android:layout_width="match_parent"
               android:layout_height="match_parent" />

           <TextView
               android:id="@+id/txt_recy_categorie"
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               tools:text="Test"
               />

           <TextView
               android:id="@+id/txt_recy_reference"
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               tools:text="Test"
               />
           <TextView
               android:id="@+id/txt_recy_nom"
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               tools:text="Test"
               />
           <TextView
               android:id="@+id/txt_recy_prix"
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               tools:text="Test"
               />
           <TextView
               android:id="@+id/txt_recy_quantite"
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               tools:text="Test"
               />
           <TextView
               android:id="@+id/txt_recy_description"
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               tools:text="Test"
               />

       </LinearLayout>



   </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

和他的行，recyclerview_row.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"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:orientation="horizontal"
   android:padding="10dp">

   <TextView
       android:id="@+id/tv_categorie_produit"
       android:layout_width="wrap_content"
       android:layout_height="match_parent"
       android:layout_weight="1"
       android:autoSizeTextType="uniform"
       android:visibility="visible"
       app:autoSizeMinTextSize="6sp"
       app:autoSizeTextType="uniform" />

   <TextView
       android:id="@+id/tv_reference_produit"
       android:layout_width="wrap_content"
       android:layout_height="match_parent"
       android:layout_weight="1"
       android:autoSizeTextType="uniform"
       android:visibility="visible"
       app:autoSizeMinTextSize="6sp"
       app:autoSizeTextType="uniform" />

   <TextView
       android:id="@+id/tv_nom_produit"
       android:layout_width="wrap_content"

       android:layout_height="match_parent"
       android:layout_weight="1"
       android:autoSizeTextType="uniform"
       android:visibility="visible"
       app:autoSizeMinTextSize="6sp"
       app:autoSizeTextType="uniform" />

   <TextView
       android:id="@+id/tv_prix_produit"
       android:layout_width="wrap_content"
       android:layout_height="match_parent"
       android:layout_weight="1"
       android:autoSizeTextType="uniform"
       android:visibility="visible"
       app:autoSizeMinTextSize="6sp"
       app:autoSizeTextType="uniform" />

   <TextView
       android:id="@+id/tv_quantite_produit"
       android:layout_width="wrap_content"
       android:layout_height="match_parent"
       android:layout_weight="1"
       android:autoSizeTextType="uniform"
       android:visibility="visible"
       app:autoSizeMinTextSize="6sp"
       app:autoSizeTextType="uniform" />

   <TextView
       android:id="@+id/tv_description_produit"
       android:layout_width="wrap_content"
       android:layout_height="match_parent"
       android:layout_weight="1"
       android:autoSizeTextType="uniform"
       android:ellipsize="end"
       android:maxLength="11"
       android:maxLines="1"
       android:scrollHorizontally="true"
       android:visibility="visible"
       app:autoSizeMinTextSize="6sp"
       app:autoSizeTextType="uniform" />


</LinearLayout>

这是 logcat 错误：

   java.lang.IllegalStateException: Could not execute method for android:onClick
       at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:414)
       at android.view.View.performClick(View.java:7448)
       at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992)
       at android.view.View.performClickInternal(View.java:7425)
       at android.view.View.access$3600(View.java:810)
       at android.view.View$PerformClick.run(View.java:28305)
       at android.os.Handler.handleCallback(Handler.java:938)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:223)
       at android.app.ActivityThread.main(ActivityThread.java:7656)
       at java.lang.reflect.Method.invoke(Native Method)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
    Caused by: java.lang.reflect.InvocationTargetException
       at java.lang.reflect.Method.invoke(Native Method)
       at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409)
       at android.view.View.performClick(View.java:7448) 
       at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992) 
       at android.view.View.performClickInternal(View.java:7425) 
       at android.view.View.access$3600(View.java:810) 
       at android.view.View$PerformClick.run(View.java:28305) 
       at android.os.Handler.handleCallback(Handler.java:938) 
       at android.os.Handler.dispatchMessage(Handler.java:99) 
       at android.os.Looper.loop(Looper.java:223) 
       at android.app.ActivityThread.main(ActivityThread.java:7656) 
       at java.lang.reflect.Method.invoke(Native Method) 
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) 
    Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.example.gestiondestocktubconcept.vue.MyRecyclerViewAdapter.notifyItemInserted(int)' on a null object reference
       at com.example.gestiondestocktubconcept.vue.liste_produits.onClickData(liste_produits.java:111)
       at java.lang.reflect.Method.invoke(Native Method) 
       at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409) 
       at android.view.View.performClick(View.java:7448) 
       at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992) 
       at android.view.View.performClickInternal(View.java:7425) 
       at android.view.View.access$3600(View.java:810) 
       at android.view.View$PerformClick.run(View.java:28305) 
       at android.os.Handler.handleCallback(Handler.java:938) 
       at android.os.Handler.dispatchMessage(Handler.java:99) 
       at android.os.Looper.loop(Looper.java:223) 
       at android.app.ActivityThread.main(ActivityThread.java:7656) 
       at java.lang.reflect.Method.invoke(Native Method) 
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) 

这是我的第一个节目之一，所以请放纵一下。