How to run Multiple case at a time in Android studio

I develop a program in android studio Where we check the number is odd or even. Everything works fine but I stuck in empty field case, I am unable to perform how to check the edit field is empty or not.

et_number = findViewById (R.id.et_number);
    b_go = findViewById (R.id.b_go);
    tv_show = findViewById (R.id.tv_show);

    b_go.setOnClickListener (new View.OnClickListener () {
        @Override
        public void onClick(View v) {
            int number = Integer.parseInt (et_number.getText().toString ());
            number = number %2;

            String city = et_number.getText().toString();

            if (number == 0|| city.isEmpty()){
                tv_show.setText ("EVEN");
                et_number.getText().clear();
                Toast.makeText (MainActivity.this, "empty", Toast.LENGTH_SHORT).show ();
            }
            else {
                tv_show.setText ("ODD");
                et_number.getText().clear();

            }
        }
    });