24 lines
848 B
Dart
24 lines
848 B
Dart
import 'package:flutter/services.dart';
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/// 金额输入过滤：仅数字 + 单小数点 + 最多 2 位小数
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///
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/// [allowNegative] 为 true 时允许开头的负号（账户余额可能为负）。
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/// 记账金额、预算不使用负号，保持默认 false。
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class AmountInputFormatter extends TextInputFormatter {
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AmountInputFormatter({this.allowNegative = false});
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final bool allowNegative;
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static final _positiveRegex = RegExp(r'^\d*\.?\d{0,2}$');
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static final _negativeRegex = RegExp(r'^-?\d*\.?\d{0,2}$');
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@override
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TextEditingValue formatEditUpdate(TextEditingValue oldValue, TextEditingValue newValue) {
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final text = newValue.text;
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if (text.isEmpty) return newValue;
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final regex = allowNegative ? _negativeRegex : _positiveRegex;
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if (!regex.hasMatch(text)) return oldValue;
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return newValue;
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}
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}
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