Prime numbers 6 digits

I have been offered a mobile application where you ask for the position of a prime number and it returns the prime number in that position. Specifically, I start by storing only the prime numbers in an ArrayList and then I have optimized everything that has occurred to me so as not to block the mobile but in the end it explodes, I don't know what further optimizations to make, can someone help me please? Thank you very much and greetings to all.

Here I show the code:

All of the following is inside a package and I import the corresponding libraries, which I do not put here because it gives me an error and does not let me publish.

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

   static ArrayList<Integer> nprimos = new ArrayList<Integer>();


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

        getSupportActionBar().setDisplayShowHomeEnabled(true);
        getSupportActionBar().setLogo(R.mipmap.ic_launcher);
        getSupportActionBar().setDisplayUseLogoEnabled(true);

        Button btnCalcular=findViewById(R.id.btnCalcular);
        btnCalcular.setOnClickListener(this);

        int numero=2;
        boolean primo=false;
        nprimos.add(1);//Hago un add inicial en el ArrayList

        for(int j=0;j<100000;j++){//Hago el bucle for hasta 100000 posiciones
            primo=true;
            for(int i=2; i<nprimos.size(); i++)//Hago el bucle for mientras sea menor del tamaño
                //del ArrayList
            {
                if(numero%nprimos.get(i)==0) {//divide solo entre los números primos
                    primo = false;//Si no es primo
                    break;//termina el for y salta a numero++
                }
            }
            if(primo)
            {//Si el número es primo le añado al ArrayList
                nprimos.add(numero);
            }//incremento la variable número y sube arriba para hacer la division en el if
            //mientras j siga siendo menor de 100000
            numero++;
        }
    }

    public void onClick(View v){

        EditText ed1=findViewById(R.id.ed1);

        int num = Integer.parseInt(ed1.getText().toString());
        TextView t=findViewById(R.id.txtResultado);
        //Al pinchar ya empezamos con un ArrayList lleno de números primos
        if(num<nprimos.size()){
            t.setText("El número primo es: "+nprimos.get(num));
        }
        else{
            int contador=0;
            int limite=num-nprimos.size();
            int numero=nprimos.get(nprimos.size()-1);
            boolean primo=false;

            while(contador!=limite) {
                primo=true;
                for(int i=2; i<nprimos.size(); i++)
                {
                    if(numero%nprimos.get(i)==0) {
                        primo=false;
                        break;
                    }
                }
                if(primo)
                {
                    contador++;
                    nprimos.add(numero);
                }
                numero++;
            }
            t.setText("El número primo es: "+nprimos.get(num-1));
        }
    }
}