title: Save ArrayList of custom objects and add a new object to ArrayList
body: <p>I'm having an issue with saving the instance of an ArrayList of custom objects in an Activity and then retreiving it after doing some stuff in another Activity. Inside the first Activity (which has the ArrayList), there is a button to start a second activity. Inside this second Activity the user is asked to create a new object that will be added afterwards in the ArrayList of the first Activity, so that when the second Activity finishes the first Activity is shown again with a ListView of all the objects (including the last one created). The problem I'm facing is that only the last object created is being shown in the ListView.</p>
  
  <p>Here is the code of the first Activity:    </p>
  
  <pre><code>public class CargasMin extends AppCompatActivity implements View.OnClickListener {
  
  RelativeLayout rl_CargasMin;
  
  ImageButton bt_AdDep;
  Button bt_CalcCargas;
  
  ListView listView_Dep;
  
  ArrayList&lt;Dependencia&gt; listaDeDependencias = new ArrayList&lt;Dependencia&gt;();
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.min_cargas);
  
      rl_CargasMin = (RelativeLayout) findViewById(R.id.cargasMinLayout);
  
      bt_AdDep = (ImageButton) findViewById(R.id.bt_AdDep_CargasMin);
      bt_CalcCargas = (Button) findViewById(R.id.bt_CalcCargas_CargasMin);
      bt_AdDep.setOnClickListener(this);
      bt_CalcCargas.setOnClickListener(this);
  
      // This seems not to be working!
      if(savedInstanceState == null) { }
      else {
          listaDeDependencias = savedInstanceState.getParcelableArrayList("key");
      }
  
      // Get last object created
      Intent intent_de_AdDep = getIntent();
      Dependencia dependenciaAAdicionar = (Dependencia) intent_de_AdDep.getParcelableExtra("novaDependencia");
      if(dependenciaAAdicionar == null) { }
      else {
          listaDeDependencias.add(dependenciaAAdicionar);
      }
  
      //Cria Adapter pra mostrar dependencias na ListView
      DependenciaAdapter adapterDeDependencias = new DependenciaAdapter(this, R.layout.adapter_dependencia, listaDeDependencias);
  
      //Seta Adapter
      listView_Dep = (ListView) findViewById(R.id.listView_Dep_CargasMin);
      listView_Dep.setAdapter(adapterDeDependencias);
  }
  
  
  @Override
  public void onClick(View v) {
      switch(v.getId()) {
          case R.id.bt_AdDep_CargasMin:
              Intent intent_AdDep = new Intent(CargasMin.this, AdDep.class);
              startActivity(intent_AdDep);
              break;
          case R.id.bt_CalcCargas_CargasMin:
              //
              break;
      }
  }
  
  
  @Override
  protected void onSaveInstanceState(Bundle outState) {
      // Aqui se salva a listaDeDependencias quando a Atividade eh momentaneamente fechada.
      outState.putParcelableArrayList("key", listaDeDependencias);
      super.onSaveInstanceState(outState);
      }
  }
  </code></pre>
  
  <p>This is the code of my custom class Dependencia:</p>
  
  <pre><code>public class Dependencia implements Parcelable {
  String nome;
  int tipo;
  
  float largura = 0;
  float comprimento = 0;
  float area = 0;
  float perimetro = 0;
  
  // Constructor da classe Dependencia.
  public Dependencia(String nomeDep, int tipoDep) {
      nome = nomeDep;
      tipo = tipoDep;
  }
  
  private Dependencia(Parcel in) {
      nome = in.readString();
      tipo = in.readInt();
      largura = in.readFloat();
      comprimento = in.readFloat();
      area = in.readFloat();
      perimetro = in.readFloat();
  }
  
  public int describeContents() {
      return 0;
  }
  
  public void writeToParcel(Parcel out, int flags) {
      out.writeString(nome);
      out.writeInt(tipo);
      out.writeFloat(largura);
      out.writeFloat(comprimento);
      out.writeFloat(area);
      out.writeFloat(perimetro);
  }
  
  public static final Parcelable.Creator&lt;Dependencia&gt; CREATOR = new Parcelable.Creator&lt;Dependencia&gt;() {
      public Dependencia createFromParcel(Parcel in) {
          return new Dependencia(in);
      }
  
      public Dependencia[] newArray(int size) {
          return new Dependencia[size];
      }
  };
  }
  </code></pre>
  
  <p>And this is the code of the second Activity:</p>
  
  <pre><code>public class AdDep extends AppCompatActivity implements View.OnClickListener {
  
  RelativeLayout rl_AdDep;
  
  EditText et_Nome;
  EditText et_Largura;
  EditText et_Comprimento;
  EditText et_Area;
  EditText et_Perimetro;
  
  Spinner spinner_Tipo;
  String vetorTipo[];
  int tipoEscolhido;
  
  Button bt_AdDep1;
  Button bt_AdDep2;
  
  Dependencia novaDependencia;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.dep_ad);
  
      rl_AdDep = (RelativeLayout)findViewById(R.id.adDepLayout);
  
      et_Nome = (EditText) findViewById(R.id.et_Nome_AdDep);
      et_Largura = (EditText) findViewById(R.id.et_Largura_AdDep);
      et_Comprimento = (EditText) findViewById(R.id.et_Comprimento_AdDep);
      et_Area = (EditText) findViewById(R.id.et_Area_AdDep);
      et_Perimetro = (EditText) findViewById(R.id.et_Perimetro_AdDep);
  
      spinner_Tipo = (Spinner) findViewById(R.id.spinner_Tipo_AdDep);
  
      bt_AdDep1 = (Button) findViewById(R.id.bt_AdDep1);
      bt_AdDep2 = (Button) findViewById(R.id.bt_AdDep2);
  
  
      // Adicionando opcoes no spinner
      vetorTipo = new String[5];
      vetorTipo[0] = "Banheiro";
      vetorTipo[1] = "Varanda";
      vetorTipo[2] = "Cozinha/Copa/Serviço/etc.";
      vetorTipo[3] = "Sala/Dormitório";
      vetorTipo[4] = "Outro";
  
      // Criando ArrayAdapter de strings pro spinner
      ArrayAdapter&lt;String&gt; adapterTipo = new ArrayAdapter&lt;String&gt;(AdDep.this, android.R.layout.simple_spinner_item, vetorTipo);
  
      // Setando o Adapter
      spinner_Tipo.setAdapter(adapterTipo);
  
      // Valor default do spinner (hint)
      spinner_Tipo.setSelection(0);
  
  
      bt_AdDep1.setOnClickListener(this);
      bt_AdDep2.setOnClickListener(this);
  }
  
  
  @Override
  public void onClick(View v) {
      if(String.valueOf(spinner_Tipo.getSelectedItem()).equals("Banheiro"))
          tipoEscolhido = 1;
      else if(String.valueOf(spinner_Tipo.getSelectedItem()).equals("Varanda"))
          tipoEscolhido = 2;
      else if(String.valueOf(spinner_Tipo.getSelectedItem()).equals("Cozinha/Copa/Serviço/etc."))
          tipoEscolhido = 3;
      else if(String.valueOf(spinner_Tipo.getSelectedItem()).equals("Sala/Dormitório"))
          tipoEscolhido = 4;
      else if(String.valueOf(spinner_Tipo.getSelectedItem()).equals("Outro"))
          tipoEscolhido = 5;
  
      novaDependencia = new Dependencia(et_Nome.getText().toString(), tipoEscolhido);
  
      switch(v.getId()) {
          case R.id.bt_AdDep1:
              novaDependencia.largura = Float.valueOf(et_Largura.getText().toString());
              novaDependencia.comprimento = Float.valueOf(et_Comprimento.getText().toString());
              break;
          case R.id.bt_AdDep2:
              novaDependencia.area = Float.valueOf(et_Area.getText().toString());
              novaDependencia.perimetro = Float.valueOf(et_Perimetro.getText().toString());
              break;
      }
  
      AlertDialog.Builder builder2 = new AlertDialog.Builder(v.getContext());
      builder2.setMessage("Deseja adicionar T.U.E. nesta dependência?").setPositiveButton("Sim", dialogClickListener).setNegativeButton("Não", dialogClickListener).show();
  }
  
  // Objeto tipo dialog criado para perguntar se usario deseja inserir TUEs
  DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog, int which) {
          switch (which){
              case DialogInterface.BUTTON_POSITIVE:
                  //Yes button clicked
                  break;
              case DialogInterface.BUTTON_NEGATIVE:
                  Intent intent_NovaDep_CargasMin = new Intent(AdDep.this, CargasMin.class);
                  intent_NovaDep_CargasMin.putExtra("novaDependencia", novaDependencia);
                  startActivity(intent_NovaDep_CargasMin);
                  break;
          }
      }
  };
  
  }
  </code></pre>
  
  <p>If anyone knows how to solve this, please share. Thanks.</p>