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;
    }    }
  }
  });