android EditText 對輸入字數和內容約制進行限制

   在做定製機時，對光敏值進行範圍控制時，以及對區號輸入時遇到對輸入字數以及輸入內容的顯示。找了好多方法，終於找到了幾種方法其中EditText的addTextChangedListener功不可沒。例如對光敏值要在0到61之間。大於61時要在輸入框中自動變為61.代碼如下：

edt.addTextChangedListener(new TextWatcher() {
   String nums = null;

   @Override
   public void afterTextChanged(Editable s) {
    // TODO Auto-generated method stub

    if (s != null && !s.equals("")) {
     if (numSmall != -1 && numBig != -1) {//最大值和最小值自設
      int a = 0;
      try {
       a = Integer.parseInt(s.toString());
      } catch (NumberFormatException e) {
       // TODO Auto-generated catch block
       a = 0;
      }
      if (a > 61)
       edt.setText("61");
      return;
     }     }
   }

   @Override
   public void beforeTextChanged(CharSequence s, int start, int count,
     int after) {
    // TODO Auto-generated method stub
    /*if (start == 4) {
     nums = s.toString();
    }*/
   }

   @Override
   public void onTextChanged(CharSequence s, int start, int before,
     int count) {
    /*
     * Toast.makeText(getBaseContext(), s + "****" + start + "***" +
     * before, 3000).show();
     */
    if (start > 1) {
     if (numSmall != -1 && numBig != -1) {
      int num = Integer.parseInt(s.toString());
      if (num > 61) {
       s = "61";
      }
      return;
     }     }
   }
  });