How to prevent a dialog from closing when a button is clicked

Question

I have a dialog with EditText for input. When I click the \"yes\" button on dialog, it will validate the input and then close the dialog. However, if the input

Answer 1

public class ComentarDialog extends DialogFragment{
private EditText comentario;

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

    LayoutInflater inflater = LayoutInflater.from(getActivity());
    View v = inflater.inflate(R.layout.dialog_comentar, null);
    comentario = (EditText)v.findViewById(R.id.etxt_comentar_dialog);

    builder.setTitle("Comentar")
           .setView(v)
           .setPositiveButton("OK", null)
           .setNegativeButton("CANCELAR", new DialogInterface.OnClickListener() {
               public void onClick(DialogInterface dialog, int id) {

               }
           });

    return builder.create();
}

@Override
public void onStart() {
    super.onStart();

    //Obtenemos el AlertDialog
    AlertDialog dialog = (AlertDialog)getDialog();

    dialog.setCanceledOnTouchOutside(false);
    dialog.setCancelable(false);//Al presionar atras no desaparece

    //Implementamos el listener del boton OK para mostrar el toast
    dialog.getButton(AlertDialog.BUTTON_POSITIVE).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if(TextUtils.isEmpty(comentario.getText())){
               Toast.makeText(getActivity(), "Ingrese un comentario", Toast.LENGTH_SHORT).show();
               return;
            }
            else{
                ((AlertDialog)getDialog()).dismiss();
            }
        }
    });

    //Personalizamos
    Resources res = getResources();

    //Buttons
    Button positive_button = dialog.getButton(DialogInterface.BUTTON_POSITIVE);
    positive_button.setBackground(res.getDrawable(R.drawable.btn_selector_dialog));

    Button negative_button =  dialog.getButton(DialogInterface.BUTTON_NEGATIVE);
    negative_button.setBackground(res.getDrawable(R.drawable.btn_selector_dialog));

    int color = Color.parseColor("#304f5a");

    //Title
    int titleId = res.getIdentifier("alertTitle", "id", "android");
    View title = dialog.findViewById(titleId);
    if (title != null) {
        ((TextView) title).setTextColor(color);
    }

    //Title divider
    int titleDividerId = res.getIdentifier("titleDivider", "id", "android");
    View titleDivider = dialog.findViewById(titleDividerId);
    if (titleDivider != null) {
        titleDivider.setBackgroundColor(res.getColor(R.color.list_menu_divider));
    }
}
}