title: How to find day of week for Intended day
body: <p>i don't know how can i find a day of week which i want?</p>
  
  <p>for example :</p>
  
  <pre><code>SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
  Calendar calendar = Calendar.getInstance();
  String s="2019-10-07";
          try {
              calendar.setTime(simpleDateFormat.parse(s));
              if(Calendar.DAY_OF_WEEK == 2){
                  Toast.makeText(this, "Mo", Toast.LENGTH_SHORT).show();
              }
          } catch (ParseException e) {
              e.printStackTrace();
          }
  </code></pre>
  
  <p>but it does not work correct! current day of calendar just Considered, not my specified day.</p>