EditText把光标放在文本的末尾处

 private TextWatcher textWatcher = new TextWatcher() {
        @Override
        public void afterTextChanged(Editable s) {
        }
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                                      int after) {
        }
        @Override
        public void onTextChanged(CharSequence s, int start, int before,
                                  int count) {
            etS.setSelection(s.toString().length());
        }