crush on button click when i try to add dinamically items in listview : I have an activity named EfortActivity which contains 3 EditText, a Spinner and a RadioGroup and a Button - saveButton. My purpose is to add data dinamically in a ListView(the listView is implemented in another acitivity called HistoryActivity). 

The problem is that when I click o the saveButton my app crash. 

Here is the code in EfortActivity: 

    public class EfortMonitorizareActivity extends AppCompatActivity {
    
    RadioGroup radioGroupDaNu;
    Spinner spinnerTip;
    EditText editTextDurata;
    EditText editTextInainte;
    EditText editTextDupa;
    Intent intent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_efort_monitorizare);
        intent = getIntent();   
        initializareComponente();    
    }

    private void initializareComponente() {
        radioGroupDaNu = (RadioGroup) findViewById(R.id.rg_activitateDANU);
        spinnerTip = (Spinner) findViewById(R.id.spin_tip_efort);
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(getApplicationContext(),
                R.array.TipEfort, R.layout.support_simple_spinner_dropdown_item);
        spinnerTip.setAdapter(adapter);
        editTextDurata = (EditText) findViewById(R.id.edt_durataAnt_efort);
        editTextInainte = (EditText) findViewById(R.id.edt_greuteInainteAnt_efort);
        editTextDupa = (EditText) findViewById(R.id.edt_greutateDupaAnt_efort);

        Button btn_inregistrareDate = (Button) findViewById(R.id.btn_adaugaDate_efort);
        btn_inregistrareDate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (validare()) {
                    Efort efort = createPlayerFromComponents();
                    if (efort != null) {
                        intent.putExtra(Constants.ADD_EFORT_KEY,efort);
                        setResult(RESULT_OK,intent);
                        finish();
                    }
                }
            }
        });
    }

    private Efort createPlayerFromComponents() {
        
        RadioButton checkDaNu = (RadioButton) findViewById(radioGroupDaNu.getCheckedRadioButtonId());
        String radioDaNu = checkDaNu.getText().toString();
        String tip = spinnerTip.getSelectedItem().toString();
        Integer durata = Integer.parseInt(editTextDurata.getText().toString());
        Integer inainte = Integer.parseInt(editTextInainte.getText().toString());
        Integer dupa = Integer.parseInt(editTextDupa.getText().toString());

        return new Efort(radioDaNu, tip, durata, inainte, dupa);
    }

    private boolean validare() {
         
        RadioButton nu = (RadioButton) findViewById(R.id.button_nu_efort);
        
        if (editTextDurata.getText() == null || editTextDurata.getText().toString().trim().isEmpty()) {
            Toast.makeText(getApplicationContext(), R.string.addplayer_number_error, Toast.LENGTH_SHORT).show();
            return false;
        }
        if (editTextInainte.getText() == null || editTextDurata.getText().toString().trim().isEmpty()) {
            Toast.makeText(getApplicationContext(), R.string.addplayer_number_error, Toast.LENGTH_SHORT).show();
            return false;
        }
        if (editTextDupa.getText() == null || editTextDurata.getText().toString().trim().isEmpty()) {
            Toast.makeText(getApplicationContext(), R.string.addplayer_number_error, Toast.LENGTH_SHORT).show();
            return false;
        }         }

Here is the code for HistoryActivity:

public class IstoricActivity extends AppCompatActivity {

    ListView lvEfort;
    List<String> listaEfort = new ArrayList<>();
    Button deconectare;

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

        deconectare=(Button)findViewById(R.id.btn_deconectareIstoric);
        deconectare.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                finish();
            }
        });
        //initializare componente
        lvEfort = (ListView) findViewById(R.id.lw_listaEfort);
        Efort efortDefault = new Efort("Da", "Tennis", 40, 55, 53);
        listaEfort.add(efortDefault.toString());

        //declarare + initializare adapter
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, listaEfort);
        lvEfort.setAdapter(adapter);
        adapter.notifyDataSetChanged();
        }
    }

And the class Efort: 

public class Efort implements Parcelable {
   
    private String radioDaNu;
    private String tip;
    private Integer durata;
    private Integer inainte;
    private Integer dupa;


    public Efort(String radioDaNu, String tip, Integer durata, Integer inainte, Integer dupa) {        
        this.radioDaNu = radioDaNu;
        this.tip = tip;
        this.durata = durata;
        this.inainte = inainte;
        this.dupa = dupa;
    }
    
    public String getRadioDaNu() {
        return radioDaNu;
    }

    public void setRadioDaNu(String radioDaNu) {
        this.radioDaNu = radioDaNu;
    }

    public String getTip() {
        return tip;
    }

    public void setTip(String tip) {
        this.tip = tip;
    }

    public Integer getDurata() {
        return durata;
    }

    public void setDurata(Integer durata) {
        this.durata = durata;
    }

    public Integer getInainte() {
        return inainte;
    }

    public void setInainte(Integer inainte) {
        this.inainte = inainte;
    }

    public Integer getDupa() {
        return dupa;
    }

    public void setDupa(Integer dupa) {
        this.dupa = dupa;
    }

    @Override
    public String toString() {
        return "Efort{" +
                // ", datePicker=" + datePicker +
                ", Activitate efort  :" + radioDaNu +
                ", tip : '" + tip + '\'' +
                ", tipm de : " + durata +
                ", inainte de antrenamnet aveam : " + inainte +
                ", dupa antrenamnet am : " + dupa +
                '}';
    }

    public Efort(Parcel in) {
        this.radioDaNu = in.readString();
        this.tip = in.readString();
        this.durata = in.readInt();
        this.inainte = in.readInt();
        this.dupa = in.readInt();
    }

    public static Parcelable.Creator<Efort> CREATOR = new Creator<Efort>() {
        @Override
        public Efort createFromParcel(Parcel parcel) {
            return new Efort(parcel);
        }

        @Override
        public Efort[] newArray(int i) {
            return new Efort[i];
        }
    };

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeString(radioDaNu);
        parcel.writeString(tip);
        parcel.writeInt(durata);
        parcel.writeInt(inainte);
        parcel.writeInt(dupa);
    }
}
