TextWatcher.java

/* 
 * There are 3 methods to the TextWatcher interface. 
 * But in most scenarios we need to use only one method.
 * This means ideally the remaining two methods have no use and should
 * not be part of the interface. This is in violation of the ISP principle
 */
editText.addTextChangedListener(new TextWatcher() {
      @Override
      public void beforeTextChanged(CharSequence s, int start, int count, int after) {
          
      }

      @Override
      public void onTextChanged(CharSequence s, int start, int before, int count) {
          /* In most of the scenarios this is the only method we use. The other methods are pointless in these cases. */
      }

      @Override
      public void afterTextChanged(Editable editable) {
          
      }
  });