在做定制機時，對光敏值進行范圍控制時，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，終于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。大于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;

}? ? }

}

? });