AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
                builder.setTitle("Nueva reserva");

                LayoutInflater inflater = getLayoutInflater();
                View dialogView = inflater.inflate(R.layout.alert_dialog, null);
                builder.setView(dialogView);



                    numPcSpinner =dialogView.findViewById(R.id.spinnerNumPc);
                    ArrayAdapter<CharSequence> adapterPc = ArrayAdapter.createFromResource(MainActivity.this,
                            R.array.spinnerPc, android.R.layout.simple_spinner_item);
                    adapterPc.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

                    numPcSpinner.setAdapter(adapterPc);


                    numHorasSpinner = dialogView.findViewById(R.id.spinnerHoras);
                    ArrayAdapter<CharSequence> adapterHoras = ArrayAdapter.createFromResource(MainActivity.this,
                            R.array.spinnerHoras, android.R.layout.simple_spinner_item);
                    adapterHoras.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                    numPcSpinner.setAdapter(adapterHoras);



                    diasSpinner = dialogView.findViewById(R.id.spinnerDia);
                    ArrayAdapter<CharSequence> adapterDias = ArrayAdapter.createFromResource(MainActivity.this,
                            R.array.spinnerDia, android.R.layout.simple_spinner_item);
                    adapterDias.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

                    numPcSpinner.setAdapter(adapterDias);