Ytukyg

I am getting a problem with my project in Android Studio.
What I am trying to do is when I click a button (what opens another activity) and in that activity I write data from a person.
Then I save this data and the app get back to the main. The next button what does is create a Toast that shows data from the person, but the Toast is returning me null. I don't know what I am doing wrong.

   public class PrincipalActivity extends AppCompatActivity implements View.OnClickListener {



    Button btnObreActivitat1, btnToastDadesPersona;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_principal);



        btnObreActivitat1 = findViewById(R.id.btnObreActivitat1);

        btnObreActivitat1.setOnClickListener(this);

        btnToastDadesPersona = findViewById(R.id.btnToastDadesPersona);

        btnToastDadesPersona.setOnClickListener(this);

    }



    @Override

    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {

        if (resultCode == RESULT_CANCELED) {

            Toast.makeText(this, "Resposta invalida", Toast.LENGTH_SHORT);

        } else {

            switch (requestCode) {

                case 5:

                    setTitle(data.getStringExtra("RESPOSTA"));

                    break;

            }

        }

    }



    @Override

    public void onClick(View v) {

        Intent intencio;

        StringBuilder sbUri = new StringBuilder();



        switch (v.getId()){

            case R.id.btnObreActivitat1:

                intencio = new Intent(this,Activitat1.class);

                startActivityForResult(intencio,5);

                break;

            case R.id.btnToastDadesPersona:

                intencio = getIntent();

                String nom = intencio.getStringExtra("NOM");

                String cognom = intencio.getStringExtra("COGNOM");

                String sexe = intencio.getStringExtra("SEXE");



                Toast torrada = new Toast(this);

                LayoutInflater inflador = getLayoutInflater();

                View vista = inflador.inflate(R.layout.torrada,null);

                TextView tvMissatge = vista.findViewById(R.id.tvMissatge);

                tvMissatge.setText("Nom: " + nom + "nCognom: " + cognom +  "nSexe: " + sexe);



                torrada.setView(vista);

                torrada.setDuration(Toast.LENGTH_SHORT);

                torrada.show();

                break;

        }

    }



    @Override

    protected void onStart() {

        super.onStart();

    }

    @Override

    protected void onResume(){

        super.onResume();

    }

    @Override

    protected void onPause() {

        super.onPause();

    }

    @Override

    protected void onStop() {

        super.onStop();

    }

}

//Next activity where I write data :

 public class Activitat1 extends AppCompatActivity {

    final static String nom = "NOM";

    final static String cognom = "COGNOM";

    final static String sexe = "SEXE";



    Button btnEnviar, btnCancelar;

    EditText etNom, etCognom;

    RadioButton rbtSexe;

    RadioGroup rgpSexe;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_activitat1);



        etNom = findViewById(R.id.etNom);

        etCognom = findViewById(R.id.etCognom);

        btnEnviar = findViewById(R.id.btnEnviar);

        btnCancelar = findViewById(R.id.btnCancelar);



        rgpSexe = findViewById(R.id.rgpSexe);

        rbtSexe = findViewById(rgpSexe.getCheckedRadioButtonId());

        btnEnviar.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                Intent intencio = Activitat1.this.getIntent();

                intencio.putExtra(nom, etNom.getText().toString());

                intencio.putExtra(cognom, etCognom.getText().toString());

                intencio.putExtra(sexe,rbtSexe.getText().toString());

                startActivity(intencio);

            }

        });



        btnCancelar.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                setResult(RESULT_CANCELED);

                finish();

            }



        });

    }

}

To send back the persons data you just write after finish the Activitat1, you need to call setResult, passing an intent and then call finish. Please, take a look at this reply here to see how to do it:
https://stackoverflow.com/a/947560/3342108

in btnEnviar.setOnClickListener() you are creating a new instance startActivity(intencio); instead of returning to the parent activity setResult(RESULT_OK, intencio);finish();.

try this

 btnEnviar.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View v) {

            Intent intencio = Activitat1.this.getIntent();

            intencio.putExtra(nom, etNom.getText().toString());

            intencio.putExtra(cognom, etCognom.getText().toString());

            intencio.putExtra(sexe,rbtSexe.getText().toString());

            setResult(RESULT_OK, intencio);

            finish();        }

    });