android studio:java.lang.NullPointerException

[fouzia]

Bonjour,

je voudrais faire un spinner , quand je sélectionne une option et je clique sur le boutton l 'application m'affiche un graphe.

 

package com.example.lenovo.volley;
 
import android.app.ProgressDialog;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;
 
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.JsonArrayRequest;
import com.github.mikephil.charting.charts.BarChart;
import com.github.mikephil.charting.data.BarData;
import com.github.mikephil.charting.data.BarDataSet;
import com.github.mikephil.charting.data.BarEntry;
 
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
 
import java.util.ArrayList;
 
public class first extends AppCompatActivity implements AdapterView.OnItemSelectedListener {
 
    String[] reportings= new String[]{"nombre de vose par personne","nombre de cantacts chaque personne",
            "nombre d'audits par personne","nombre devistes de chaque personne","nombre de mission de chaque personne"};
    Spinner reporting;
    //Button rechercher;
    BarData theData;
    BarChart barChart;
    private String urlJsonArry;
 
    //private Button btnMakeArrayRequest;
    String record="";
 
    // Progress dialog
    private ProgressDialog pDialog;
    private String jsonResponse;
    ArrayList<String> employes=new ArrayList<>();
    ArrayList<BarEntry> barEntries = new ArrayList<>();
    private static String TAG1 = first.class.getSimpleName();
 
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_first);
        //rechercher=(Button)findViewById(R.id.button);
        barChart=(BarChart)findViewById(R.id.barChart);
//        YAxis rightAxis = barChart.getAxisRight();
  //      rightAxis.setDrawGridLines(false);
    //    YAxis leftAxis = barChart.getAxisLeft();
      //  leftAxis.setDrawGridLines(false);
 
 
        pDialog = new ProgressDialog(this);
        pDialog = new ProgressDialog(this);
        pDialog.setMessage("Please wait...");
        pDialog.setCancelable(false);
        reporting=(Spinner)findViewById(R.id.spinner);
        ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,reportings);
        reporting.setAdapter(adapter);
 
 
        reporting.setOnItemSelectedListener(this);
 
    }
    public void rechercher(View view){
        showpDialog();
 
        JsonArrayRequest req = new JsonArrayRequest(urlJsonArry,
                new Response.Listener<JSONArray>() {
                    @Override
                    public void onResponse(JSONArray response) {
                        Log.d(TAG1, response.toString());
 
                        try {
                            // Parsing json array response
                            // loop through each json object
 
 
                            for (int i = 0; i < response.length(); i++) {
 
 
                                JSONObject person = (JSONObject) response.get(i);
                                int Val=person.getInt("Val");
                                String user_name=person.getString("user_name");
 
                                employes.add(user_name);
                                barEntries.add(new BarEntry(Val,i));
                            }
                            BarDataSet barDataSet=new BarDataSet(barEntries,record);
                            theData = new BarData(employes,barDataSet);
                            barChart.setData(theData);
                            barChart.notifyDataSetChanged();
                            barChart.invalidate();
 
 
                        } catch (JSONException e) {
                            e.printStackTrace();
                            Toast.makeText(getApplicationContext(),
                                    "Error: " + e.getMessage(),
                                    Toast.LENGTH_LONG).show();
                        }
 
                        hidepDialog();
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                VolleyLog.d(TAG1, "Error: " + error.getMessage());
                Toast.makeText(getApplicationContext(),
                        error.getMessage(), Toast.LENGTH_SHORT).show();
                hidepDialog();
            }
        });
 
        // Adding request to request queue
        AppController.getInstance().addToRequestQueue(req);
 
    }
 
    private void showpDialog() {
        if (!pDialog.isShowing())
            pDialog.show();
    }
 
    private void hidepDialog() {
        if (pDialog.isShowing())
            pDialog.dismiss();
    }
    @Override
    public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
        switch (position)
 
        {
 
            case 0:
 
                record = "nombre de vose par personne";
                urlJsonArry="http://13.81.62.0/mobileapi/reporting?reportid=1";
 
                break;
 
            case 1:
 
                record = "nombre de cantacts chaque personne";
                urlJsonArry="http://13.81.62.0/mobileapi/reporting?reportid=2";
 
                break;
 
            case 2:
 
                record = "nombre d'audits par personne";
                urlJsonArry="http://13.81.62.0/mobileapi/reporting?reportid=3";
 
                break;
        }
    }
 
    @Override
    public void onNothingSelected(AdapterView<?> adapterView) {
 
 
    }
}

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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.lenovo.volley.first">
 
    <LinearLayout
        android:layout_width="368dp"
        android:layout_height="495dp"
        android:orientation="vertical"
        tools:layout_editor_absoluteY="8dp"
        tools:layout_editor_absoluteX="8dp">
 
        <TextView
            android:id="@+id/textView3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="0.10"
            android:text="TextView" />
 
        <Spinner
            android:id="@+id/spinner"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="0.55" />
 
        <Button
            android:id="@+id/button"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="0.10"
            android:onClick="rechercher"
            android:text="Button" />
 
        <com.github.mikephil.charting.charts.BarChart
            android:layout_width="match_parent"
            android:layout_height="363dp"></com.github.mikephil.charting.charts.BarChart>
    </LinearLayout>
</android.support.constraint.ConstraintLayout>

voila l erreur qui s'affiche 

v08-09 09:58:49.356 32742-32742/com.example.lenovo.volley E/AndroidRuntime: FATAL EXCEPTION: main
                                                                           Process: com.example.lenovo.volley, PID: 32742
                                                                           java.lang.NullPointerException: Attempt to invoke virtual method 'void com.github.mikephil.charting.charts.BarChart.setData(com.github.mikephil.charting.data.ChartData)' on a null object reference
                                                                               at com.example.lenovo.volley.first$1.onResponse(first.java:99)
                                                                               at com.example.lenovo.volley.first$1.onResponse(first.java:77)
                                                                               at com.android.volley.toolbox.JsonRequest.deliverResponse(JsonRequest.java:65)
                                                                               at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)
                                                                               at android.os.Handler.handleCallback(Handler.java:739)
                                                                               at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                               at android.os.Looper.loop(Looper.java:158)
                                                                               at android.app.ActivityThread.main(ActivityThread.java:7231)
                                                                               at java.lang.reflect.Method.invoke(Native Method)
                                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
                                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)