Failed to add Class objects to the Array List

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I have the class below:

package carcleo.com.radiosingular.classes;

import android.util.Log;
import android.widget.Toast;

import com.google.gson.JsonArray;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Array;
import java.util.ArrayList;

import cz.msebera.android.httpclient.HttpEntity;
import cz.msebera.android.httpclient.HttpResponse;
import cz.msebera.android.httpclient.client.ClientProtocolException;
import cz.msebera.android.httpclient.client.methods.HttpPost;
import cz.msebera.android.httpclient.impl.client.DefaultHttpClient;

public class JsonClass {

    InputStream input = null;
    JSONObject jObect = null;
    String json = "";

    //Recebe sua url
    public ArrayList<Clientes> getJSONFromUrl(String url) {
        //HTTP request
        try {
            // default HttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            input = httpEntity.getContent();
            BufferedReader reader = new BufferedReader(new InputStreamReader(input, "UTF-8"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;

            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }

            input.close();

            json = sb.toString();//

            // Transforma a String de resposta em um JSonObject
            jObect = new JSONObject(json);

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        }
        // retorna o objeto
        return Clientes(jObect);

    }

    private ArrayList<Clientes> Clientes (JSONObject jObect) {
       // Cria o Array List de Clientes
        ArrayList<Clientes> aCli = null;

        try {
            //Pega o primeiro índice do Array de Objetos, no caso, o array Clientes
            JSONArray clientesLista = jObect.getJSONArray("clientes"); // aqui você faz o resgate da lista

            // Transforma a JSONArray de resposta em um Array de objjeo da Classe Clientes
            for (int i = 0; i < clientesLista.length(); i++) {
                //Pega cada íncide do array e atribui a uma variável
                JSONObject jSobj = clientesLista.getJSONObject(i);
                //Indetifica os campos do objeto
                int id =  Integer.parseInt(jSobj.getString("idClientesT"));
                //int id =  jSobj.getInt("idClientesT");
                String tipo = jSobj.getString("tipo");
                String nome = jSobj.getString("nome");
               //popula o objeto da classe de clientes
                Clientes cliente = new Clientes(id, tipo, nome);
                //Adiciona o objeto de Classe criado ào Array de Clientes

                Log.v("Nome: ", cliente.getNome());

                aCli.add(cliente);
            }

        } catch (JSONException e) {
            Log.e("JSON Parser", "Erro no parsing doo objeto " + e.toString());
        }

        return aCli;

    }

}

In the method

private ArrayList<Clientes> Clientes (JSONObject jObect) {

Error when adding objects in Client Arraylist.

aCli.add(cliente);

But in doing 

Log.v("Nome: ", cliente.getNome());

On the first round of loop for, customer’s name comes out.

It seems that when the for goes to second round the error occurs.

What is wrong here?

Here is the main:

package carcleo.com.radiosingular;

import android.os.Bundle;
import android.os.StrictMode;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;

import carcleo.com.radiosingular.classes.Clientes;
import carcleo.com.radiosingular.classes.JsonClass;

public class form extends AppCompatActivity {

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

    public void listaClientes (View View) {

        if (android.os.Build.VERSION.SDK_INT > 9){
            StrictMode.ThreadPolicy policy = new
            StrictMode.ThreadPolicy.Builder().permitAll().build();
            StrictMode.setThreadPolicy(policy);
        }

        String url = "http://192.168.1.5/hotplateprensas.com.br/ws/clientest.php";
        JsonClass json = new JsonClass();
        ArrayList<Clientes> clientesLista = json.getJSONFromUrl(url);

    }

}

EDIT:

MISTAKES

Error of RUN

W/art: Before Android 4.1, method int android.support.v7.widget.DropDownListView.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView
D/OpenGLRenderer: endAllActiveAnimators on 0x9865d300 (RippleDrawable) with handle 0x983c0000
D/NetworkSecurityConfig: No Network Security Config specified, using platform default
V/Nome:: Carlos
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: carcleo.com.radiosingular, PID: 29162
    java.lang.IllegalStateException: Could not execute method for android:onClick
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
        at android.view.View.performClick(View.java:5640)
        at android.view.View$PerformClick.run(View.java:22455)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6165)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:778)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
        at android.view.View.performClick(View.java:5640) 
        at android.view.View$PerformClick.run(View.java:22455) 
        at android.os.Handler.handleCallback(Handler.java:751) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6165) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:778) 
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.util.ArrayList.add(java.lang.Object)' on a null object reference
        at carcleo.com.radiosingular.classes.JsonClass.Clientes(JsonClass.java:94)
        at carcleo.com.radiosingular.classes.JsonClass.getJSONFromUrl(JsonClass.java:67)
        at carcleo.com.radiosingular.form.listaClientes(form.java:38)
        at java.lang.reflect.Method.invoke(Native Method) 
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385) 
        at android.view.View.performClick(View.java:5640) 
        at android.view.View$PerformClick.run(View.java:22455) 
        at android.os.Handler.handleCallback(Handler.java:751) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6165) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:778) 

In time:

The Exit to:

        Log.v("clienteLista", clientesLista.toString());

is:

V/clienteLista: [{"idClientesT":"1","tipo":"s","nome":"Carlos"},{"idClientesT":"2","tipo":"s","nome":"Rogério"}]
java android android-studio

  • put error too, please

  • Might have something to do with the returns of methods?

  • probably not.. saw that down there gave a Nullpointer.. makes a Log showing the variable "clientsList" and see if there is anything null

  • added to the end of the pegunta but the output is; V/clientelist: [{"idClientesT":"1","type":"s","name":"Carlos"},{"idClientesT":"2","type":"s","name":"Rogério"}]

  • Your array is null: ArrayList<Clientes> aCli = null;. You have to create a new ArrayList<>() there.

  • um, but it’s null only until it’s populated with Acli.add(). No? In phjp we do it and it works. But thanks. It worked. | Thank you very much. Now I will post another question in order to remove that clause Strictmode.Threadpolicy = new Strictmode.ThreadPolicy.Builder(). permitAll(). build(); that if I remove the rest of the codex it does not work!

  • @Leonardo Lima. If you want to post as an answer I accept your answer!

Show 2 more comments

1 answer

2


First you’re initiating a ArrayList with nil:

ArrayList<Clientes> aCli = null;

And then trying to manipulate it on line 94, which is not allowed in Java: 

aCli.add(cliente);

In this case, the ideal is to initialize the variable with a valid object and then use it:

ArrayList<Clientes> aCli = new ArrayList<>();

This link talks more about the NullPointerException, its causes and how to avoid it.

  • thank you very much.

  • If you can help me with this other question, I would like to thank you for + https://answall.com/questions/352332/problemas-com-strictmode-threadpolicy

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