团队冲刺第二阶段07

添加了笔记中的时间戳Timestamp，点击之后可在笔记下方添加当前时间，可修改。

  private void addTimestamp () {
    Editable editable = content.getText();
    int position = content.getSelectionStart();
    DateFormat dateFormat = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT);
    String dateStamp = dateFormat.format(new Date().getTime()) + " ";
    if (noteTmp.isChecklist()) {
      if (mChecklistManager.getFocusedItemView() != null) {
        editable = mChecklistManager.getFocusedItemView().getEditText().getEditableText();
        position = mChecklistManager.getFocusedItemView().getEditText().getSelectionStart();
      } else {
        ((CheckListView) toggleChecklistView)
            .addItem(dateStamp, false, mChecklistManager.getCount());
      }
    }
    String leadSpace = position == 0 ? "" : " ";
    dateStamp = leadSpace + dateStamp;
    editable.insert(position, dateStamp);
    Selection.setSelection(editable, position + dateStamp.length());
  }