我已经找到了解决日期验证输入所需的内容。它并不完美,但对于我想做的事情来说已经足够好了。我所需要的只是看看输入格式器TextField() 的方法。这允许对输入文本进行操作,将其放入任意数量的用户定义格式。我为任何想尝试的人提供了一段代码:
class _DateFormatter extends TextInputFormatter {
@override
TextEditingValue formatEditUpdate(
TextEditingValue prevText, TextEditingValue currText) {
int selectionIndex;
// Get the previous and current input strings
String pText = prevText.text;
String cText = currText.text;
// Abbreviate lengths
int cLen = cText.length;
int pLen = pText.length;
if (cLen == 1) {
// Can only be 0, 1, 2 or 3
if (int.parse(cText) > 3) {
// Remove char
cText = '';
}
} else if (cLen == 2 && pLen == 1) {
// Days cannot be greater than 31
int dd = int.parse(cText.substring(0, 2));
if (dd == 0 || dd > 31) {
// Remove char
cText = cText.substring(0, 1);
} else {
// Add a / char
cText += '/';
}
} else if (cLen == 4) {
// Can only be 0 or 1
if (int.parse(cText.substring(3, 4)) > 1) {
// Remove char
cText = cText.substring(0, 3);
}
} else if (cLen == 5 && pLen == 4) {
// Month cannot be greater than 12
int mm = int.parse(cText.substring(3, 5));
if (mm == 0 || mm > 12) {
// Remove char
cText = cText.substring(0, 4);
} else {
// Add a / char
cText += '/';
}
} else if ((cLen == 3 && pLen == 4) || (cLen == 6 && pLen == 7)) {
// Remove / char
cText = cText.substring(0, cText.length - 1);
} else if (cLen == 3 && pLen == 2) {
if (int.parse(cText.substring(2, 3)) > 1) {
// Replace char
cText = cText.substring(0, 2) + '/';
} else {
// Insert / char
cText =
cText.substring(0, pLen) + '/' + cText.substring(pLen, pLen + 1);
}
} else if (cLen == 6 && pLen == 5) {
// Can only be 1 or 2 - if so insert a / char
int y1 = int.parse(cText.substring(5, 6));
if (y1 < 1 || y1 > 2) {
// Replace char
cText = cText.substring(0, 5) + '/';
} else {
// Insert / char
cText = cText.substring(0, 5) + '/' + cText.substring(5, 6);
}
} else if (cLen == 7) {
// Can only be 1 or 2
int y1 = int.parse(cText.substring(6, 7));
if (y1 < 1 || y1 > 2) {
// Remove char
cText = cText.substring(0, 6);
}
} else if (cLen == 8) {
// Can only be 19 or 20
int y2 = int.parse(cText.substring(6, 8));
if (y2 < 19 || y2 > 20) {
// Remove char
cText = cText.substring(0, 7);
}
}
selectionIndex = cText.length;
return TextEditingValue(
text: cText,
selection: TextSelection.collapsed(offset: selectionIndex),
);
}
}
要使用它,只需从 Textfield() 调用它,如下所示。我还合并了两个内置方法。白名单TextInputFormatter()只允许输入数字和斜线(/)字符LengthLimitingTextInputFormatter()限制允许的字符数。后者可以使用 TextField() 的 maxLength 参数来实现,但这里仅作为示例。请注意,还有一个黑名单文本输入格式化程序()这正如你所期望的那样。
白名单TextInputFormatter已删除使用FilteringTextInputFormatter.allow(RegExp("[0-9-]")),替换,并且如果您想更改分割符号(当前是"/"),请添加到正则表达式(....).
TextField(
// maxLength: 10,
keyboardType: TextInputType.datetime,
controller: _controllerDOB,
focusNode: _focusNodeDOB,
decoration: InputDecoration(
hintText: 'DD/MM/YYYY',
counterText: '',
),
inputFormatters: [
WhitelistingTextInputFormatter(RegExp("[0-9/]")),
LengthLimitingTextInputFormatter(10),
_DateFormatter(),
],
),