android EditText 对输入字数和内容范围进行限制

   在做定制机时，对光敏值进行范围控制时，以及对区号输入时遇到对输入字数以及输入内容的显示。找了好多方法，终于找到了几种方法其中EditText的addTextChangedListener功不可没。例如对光敏值要在0到61之间。大于61时要在输入框中自动变为61.代码如下：

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) {//最大值和最小值自设
      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;
     }     }
   }
  });