I need to add 4 different numbers that are going to be introduced in 4 different EditTexts by a user. I've made a code but I don't know how to take those 4 numbers and add them to have just one, can someone help me? Here's the code:

```
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class Paquetes extends AppCompatActivity implements View.OnClickListener{

Button solicitar;
Button volver;
EditText n1;
EditText n2;
EditText n3;
EditText n4;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_paquetes);
    solicitar = (Button)findViewById(R.id.button_solicitar);
    solicitar.setOnClickListener(this);
    volver = (Button)findViewById(R.id.button2_v);
    volver.setOnClickListener(this);
    n1 = (EditText)findViewById(R.id.n1);
    n2 = (EditText)findViewById(R.id.n2);
    n3 = (EditText)findViewById(R.id.n3);
    n4 = (EditText)findViewById(R.id.n4);
}

@Override
public void onClick (View v){
    switch (v.getId()) {
        EditText uno = n1.getText();
        EditText dos = n2.getText();
        EditText tres = n3.getText();
        EditText cuatro = n4.getText();
        public int n{
            n = uno + dos + tres + cuatro;
        }
        case R.id.button_solicitar:
            Toast.makeText(Paquetes.this, "¡Tu pedido ha sido solicitado!", Toast.LENGTH_LONG).show();
            startActivity(new Intent(this, Casa.class));
            break;
        case R.id.button2_v:
            startActivity(new Intent(this, Casa.class));
            break;
    }
}
}

```

Thanks in advance,