Problems Saving Sqlite Data - Android

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I am trying to save the data in Sqlite database from a form in my app, but when I click save button, the app closes and is shown the following error.

Android Studio points the error to this code snippet

student.setName(String.valueOf(fieldName.gettext()));

who is in the class

Formulariohelper

Error stack

  E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.alura.magnero2018.agendaalura, PID: 24918
    java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
        at com.alura.magnero2018.agendaalura.FormularioHelper.pegarAluno(FormularioHelper.java:73)
        at com.alura.magnero2018.agendaalura.FormularioActivity.onOptionsItemSelected(FormularioActivity.java:63)
        at android.app.Activity.onMenuItemSelected(Activity.java:3547)
        at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:436)
        at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:196)
        at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:109)
        at android.support.v7.app.AppCompatDelegateImpl.onMenuItemSelected(AppCompatDelegateImpl.java:888)
        at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:840)
        at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:158)
        at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:991)
        at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:981)
        at android.support.v7.widget.ActionMenuView.invokeItem(ActionMenuView.java:625)
        at android.support.v7.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:151)
        at android.view.View.performClick(View.java:6600)
        at android.view.View.performClickInternal(View.java:6577)
        at android.view.View.access$3100(View.java:781)
        at android.view.View$PerformClick.run(View.java:25912)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6912)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:860)
Application terminated.

Code of the Activity

package com.alura.magnero2018.agendaalura;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

import alura.modelo.Aluno;
import br.com.alura.dao.AlunoDAO;

public class FormularioActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_formulario);
        FormularioHelper helper = new FormularioHelper(this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        inflater.inflate(R.menu.activity_menu_formulario, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        FormularioHelper helper = new FormularioHelper(this);


        switch (item.getItemId())
        {
            case R.id.menu_formulario_ok:

                Aluno aluno = helper.pegarAluno();
                AlunoDAO dao = new AlunoDAO(this);
                dao.insere(aluno);
                dao.close();

                Toast.makeText(FormularioActivity.this, "Aluno" + aluno.getNome() + "salvo", Toast.LENGTH_LONG).show();
                Intent abrirLista = new Intent(FormularioActivity.this, ListaAlunosActivity.class);
               startActivity(abrirLista);

                finish();
                break;
        }
        return super.onOptionsItemSelected(item);
    }
}

Java student.

package alura.modelo;

import android.text.Editable;

public class Aluno {
    private Long id;
    private String nome;
    private String endereco;
    private String telefone;
    private String site;
    private Double nota;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getNome() {
        return nome;
    }

    public void setNome(String nome) {
        this.nome = nome;
    }

    public String getEndereco() {
        return endereco;
    }

    public void setEndereco(String endereco) {
        this.endereco = endereco;
    }

    public String getTelefone() {
        return telefone;
    }

    public void setTelefone(String telefone) {
        this.telefone = telefone;
    }

    public String getSite() {
        return site;
    }

    public void setSite(String site) {
        this.site = site;
    }

    public Double getNota() {
        return nota;
    }

    public void setNota(Double nota) {
        this.nota = nota;
    }

    public String toString() {
        return getId() + " " + getNome();
    }
}

Formulariohelper.java

package com.alura.magnero2018.agendaalura;

import android.widget.EditText;
import android.widget.RatingBar;

import com.alura.magnero2018.agendaalura.FormularioActivity;
import com.alura.magnero2018.agendaalura.R;


import alura.modelo.Aluno;

public class FormularioHelper
{
    private EditText campoNome;
    private EditText campoEndereco;
    private EditText campoSitesPessoais;
    private EditText campoTelefone;
    private RatingBar campoNotas;

    public EditText getCampoNome() {
        return campoNome;
    }

    public void setCampoNome(EditText campoNome) {
        this.campoNome = campoNome;
    }

    public EditText getCampoEndereco() {
        return campoEndereco;
    }

    public void setCampoEndereco(EditText campoEndereco) {
        this.campoEndereco = campoEndereco;
    }

    public EditText getCampoSitesPessoais() {
        return campoSitesPessoais;
    }

    public void setCampoSitesPessoais(EditText campoSitesPessoais) {
        this.campoSitesPessoais = campoSitesPessoais;
    }

    public EditText getCampoTelefone() {
        return campoTelefone;
    }

    public void setCampoTelefone(EditText campoTelefone) {
        this.campoTelefone = campoTelefone;
    }

    public RatingBar getCampoNotas() {
        return campoNotas;
    }

    public void setCampoNotas(RatingBar campoNotas) {
        this.campoNotas = campoNotas;
    }


    public FormularioHelper(FormularioActivity activity)
    {
        EditText campoNome = activity.findViewById(R.id.nome);
        EditText campoEndereco = activity.findViewById(R.id.endereco);
        EditText campoSitesPessoais = activity.findViewById(R.id.sitesPessoais);
        EditText campoTelefone = activity.findViewById(R.id.telefone);
        RatingBar campoNotas = (RatingBar) activity.findViewById(R.id.notas);
    }

    public Aluno pegarAluno()
    {
        Aluno aluno = new Aluno();
        aluno.setNome(String.valueOf(campoNome.getText()));
        aluno.setEndereco(String.valueOf(campoEndereco.getText()));
        aluno.setSite(String.valueOf(campoSitesPessoais.getText()));
        aluno.setTelefone(String.valueOf(campoTelefone.getText()));
        aluno.setNota(Double.valueOf(campoNotas.getProgress()));

        return aluno;
    }
}

Alunodao.java

package br.com.alura.dao;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.DatabaseErrorHandler;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import java.util.ArrayList;
import java.util.List;

import alura.modelo.Aluno;

public class AlunoDAO extends SQLiteOpenHelper
{

    public AlunoDAO (Context context) {
        super(context, "Agenda", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String sql = "CREATE TABLE Alunos (id INTEGER PRIMARY KEY, nome TEXT NOT NULL, endereco TEXT, site TEXT, nota REAL);";

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
    {
        String sql = "DROP TABLE IF EXISTS Alunos";
        db.execSQL(sql);
        onCreate(db);
    }

    public void insere(Aluno aluno)
    {
        SQLiteDatabase db = getWritableDatabase();

        ContentValues dados = new ContentValues();
        dados.put("nome", aluno.getNome());
        dados.put("endereco", aluno.getEndereco());
        dados.put("telefone", aluno.getTelefone());
        dados.put("site", aluno.getSite());
        dados.put("nota", aluno.getNota());

        db.insert("Alunos", null, dados);
    }

    public List<Aluno> buscaAlunos()
    {
        String sql = "SELECT * FROM Alunos;";
        SQLiteDatabase db = getReadableDatabase();
        Cursor c = db.rawQuery(sql, null);

        List<Aluno> alunos = new ArrayList<Aluno>();
        while (c.moveToNext())
        {
            Aluno aluno = new Aluno();
            aluno.setId(c.getLong(c.getColumnIndex("id")));
            aluno.setNome(c.getString(c.getColumnIndex("nome")));
            aluno.setEndereco(c.getString(c.getColumnIndex("endereco")));
            aluno.setTelefone(c.getString(c.getColumnIndex("telefone")));
            aluno.setSite(c.getString(c.getColumnIndex("site")));
            aluno.setNota(c.getDouble(c.getColumnIndex("nota")));
        }

        c.close();
        return alunos;
    }
}
android android-activity
  • 2

    Could present the error stack ?

  • 1

    The problem is in Sqlite > Caused by: android.database.sqlite.SQLiteException: no such table: Alunos this table was not created or does not exist.

  • You have a @ramaral reply here > https://answall.com/questions/180678/erro-savedados-sqlite-no-such-table

  • If the extension answer does not solve, because it may be different, put the code of the creation of the database and tables

  • 2

    Just vc uninstall the app before compiling again, will resolve!

  • What @Leonardodias said is right! This could be it!

  • 2

    I uninstalled the app and modified the Activity that should be started first. Now the app runs, but I can’t save in the bank. I edited the post and put the new error stack.

Show 2 more comments

2 answers

1


The problem is in the builder of FormularioHelper which is used in Activity:

public boolean onOptionsItemSelected(MenuItem item)
{
    FormularioHelper helper = new FormularioHelper(this); // <-- AQUI

    ... mais códigos ...

Your builder is like this:

public FormularioHelper(FormularioActivity activity)
{
    EditText campoNome = activity.findViewById(R.id.nome);
    EditText campoEndereco = activity.findViewById(R.id.endereco);
    EditText campoSitesPessoais = activity.findViewById(R.id.sitesPessoais);
    EditText campoTelefone = activity.findViewById(R.id.telefone);
    RatingBar campoNotas = (RatingBar) activity.findViewById(R.id.notas);
}

His idea, it seems to me, was to define the attributes of this class. But that’s not what you did! There you create 5 NEW variables that are not being used.

So when you try to recover the Views values they are null causing this error:

'android.text.Editable android.widget.EditText.getText()' on a null object reference

As the message said, the reference (id) is null.

To fix this, just do the following:

public FormularioHelper(FormularioActivity activity)
{
    this.campoNome = activity.findViewById(R.id.nome);
    this.campoEndereco = activity.findViewById(R.id.endereco);
    this.campoSitesPessoais = activity.findViewById(R.id.sitesPessoais);
    this.campoTelefone = activity.findViewById(R.id.telefone);
    this.campoNotas = (RatingBar) activity.findViewById(R.id.notas);
}

0

I had some problems with the creation and insertion of data in the table too.

Follow the functional codes of my solution

Formularioactivity.java

package com.alura.magnero2018.agendaalura;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

import alura.modelo.Aluno;
import br.com.alura.dao.AlunoDAO;

public class FormularioActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_formulario);
        FormularioHelper helper = new FormularioHelper(this);
     /*   Button btnSalvar = findViewById(R.id.btnSalvar);

        btnSalvar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                /* insere uma mensagem em forma de pop up na tela do usuario
                Parâmetros da função
                contexto (activity atual o qual a função será chamada)
                mensagem que deseaja inserir no pop up
                tempo que a mensagem deve estar visível

                Toast.makeText(FormularioActivity.this, "Usuário salvo com sucesso!", Toast.LENGTH_LONG).show();
                Intent abrirLista = new Intent(FormularioActivity.this, ListaAlunosActivity.class);
                finish();
            }
        }); */


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        /*cria um objeto do tipo MenuInflater, o qual é responsável por criar objetos do tipo menu, a partir de um
        arquivo xml
         */
        MenuInflater inflater = getMenuInflater();
        /*metodo que pega a referencia do arquivo xml e pega item por item e vai criando os MenuItem e adicionando no menu */
        inflater.inflate(R.menu.activity_menu_formulario, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) //switch vai aqui
    {
        FormularioHelper helper = new FormularioHelper(this);

        switch (item.getItemId())
        {
            case R.id.menu_formulario_ok:

                Aluno aluno = helper.pegarAluno();
                AlunoDAO dao = new AlunoDAO(this);
                dao.insere(aluno);
                dao.close();

                Toast.makeText(FormularioActivity.this, "Aluno " + aluno.getNome() + " salvo", Toast.LENGTH_LONG).show();
                Intent abrirLista = new Intent(FormularioActivity.this, ListaAlunosActivity.class);
               startActivity(abrirLista);

                finish();
                break;
        }
        return super.onOptionsItemSelected(item);
    }
}

Alunodao.java

package br.com.alura.dao;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.DatabaseErrorHandler;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import java.util.ArrayList;
import java.util.List;

import alura.modelo.Aluno;

public class AlunoDAO extends SQLiteOpenHelper
{

    public AlunoDAO (Context context) {
        super(context, "Agenda", null, 2);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String sql = "CREATE TABLE Alunos (id INTEGER PRIMARY KEY, nome TEXT NOT NULL, endereco TEXT, site TEXT, telefone TEXT, nota REAL);";
        db.execSQL(sql);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
    {
        String sql = "DROP TABLE IF EXISTS Alunos";
        db.execSQL(sql);
        onCreate(db);
    }

    public void insere(Aluno aluno)
    {
        SQLiteDatabase db = getWritableDatabase();

        ContentValues dados = new ContentValues();
        dados.put("nome", aluno.getNome());
        dados.put("endereco", aluno.getEndereco());
        dados.put("telefone", aluno.getTelefone());
        dados.put("site", aluno.getSite());
        dados.put("nota", aluno.getNota());

        db.insert("Alunos", null, dados);
        db.close();
    }

    public List<Aluno> buscaAlunos()
    {
        String sql = "SELECT * FROM Alunos;";
        SQLiteDatabase db = getReadableDatabase();
        Cursor c = db.rawQuery(sql, null);

        List<Aluno> alunos = new ArrayList<Aluno>();
        while (c.moveToNext())
        {
            Aluno aluno = new Aluno();
            aluno.setId(c.getLong(c.getColumnIndex("id")));
            aluno.setNome(c.getString(c.getColumnIndex("nome")));
            aluno.setEndereco(c.getString(c.getColumnIndex("endereco")));
            aluno.setTelefone(c.getString(c.getColumnIndex("telefone")));
            aluno.setSite(c.getString(c.getColumnIndex("site")));
            aluno.setNota(c.getDouble(c.getColumnIndex("nota")));
        }

        c.close();
        return alunos;
    }
}

Java student.

package alura.modelo;

import android.support.annotation.NonNull;
import android.text.Editable;

public class Aluno {
    private Long id;
    private String nome;
    private String endereco;
    private String telefone;
    private String site;
    private Double nota;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getNome() {
        return nome;
    }

    public void setNome(String nome) {
        this.nome = nome;
    }

    public String getEndereco() {
        return endereco;
    }

    public void setEndereco(String endereco) {
        this.endereco = endereco;
    }

    public String getTelefone() {
        return telefone;
    }

    public void setTelefone(String telefone) {
        this.telefone = telefone;
    }

    public String getSite() {
        return site;
    }

    public void setSite(String site) {
        this.site = site;
    }

    public Double getNota() {
        return nota;
    }

    public void setNota(Double nota) {
        this.nota = nota;
    }

    @NonNull
    public String toString() {
        return getId() + " " + getNome();
    }
}

Formulariohelper.java

package com.alura.magnero2018.agendaalura;

import android.widget.EditText;
import android.widget.RatingBar;

import com.alura.magnero2018.agendaalura.FormularioActivity;
import com.alura.magnero2018.agendaalura.R;


import alura.modelo.Aluno;

public class FormularioHelper
{
    private EditText campoNome;
    private EditText campoEndereco;
    private EditText campoSitesPessoais;
    private EditText campoTelefone;
    private RatingBar campoNotas;

    public EditText getCampoNome() {
        return campoNome;
    }

    public void setCampoNome(EditText campoNome) {
        this.campoNome = campoNome;
    }

    public EditText getCampoEndereco() {
        return campoEndereco;
    }

    public void setCampoEndereco(EditText campoEndereco) {
        this.campoEndereco = campoEndereco;
    }

    public EditText getCampoSitesPessoais() {
        return campoSitesPessoais;
    }

    public void setCampoSitesPessoais(EditText campoSitesPessoais) {
        this.campoSitesPessoais = campoSitesPessoais;
    }

    public EditText getCampoTelefone() {
        return campoTelefone;
    }

    public void setCampoTelefone(EditText campoTelefone) {
        this.campoTelefone = campoTelefone;
    }

    public RatingBar getCampoNotas() {
        return campoNotas;
    }

    public void setCampoNotas(RatingBar campoNotas) {
        this.campoNotas = campoNotas;
    }


    public FormularioHelper(FormularioActivity activity)
    {
        this.campoNome = activity.findViewById(R.id.nome);
        this.campoEndereco = activity.findViewById(R.id.endereco);
        this.campoSitesPessoais = activity.findViewById(R.id.sitesPessoais);
        this.campoTelefone = activity.findViewById(R.id.telefone);
        this.campoNotas = (RatingBar) activity.findViewById(R.id.notas);
    }

    public Aluno pegarAluno()
    {
        Aluno aluno = new Aluno();
        aluno.setNome(String.valueOf(campoNome.getText()));
        aluno.setEndereco(String.valueOf(campoEndereco.getText()));
        aluno.setSite(String.valueOf(campoSitesPessoais.getText()));
        aluno.setTelefone(String.valueOf(campoTelefone.getText()));
        aluno.setNota(Double.valueOf(campoNotas.getProgress()));

        return aluno;
    }
}

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