51 lines
1.6 KiB
Dart
51 lines
1.6 KiB
Dart
// ignore_for_file: file_names
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import 'package:flutter/services.dart';
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class ThousandsSeparatorInputFormatter extends TextInputFormatter {
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static const separator = ','; // Change this to '.' for other locales
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@override
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TextEditingValue formatEditUpdate(
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TextEditingValue oldValue, TextEditingValue newValue) {
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// Short-circuit if the new value is empty
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if (newValue.text.isEmpty) {
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return newValue.copyWith(text: '');
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}
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// Handle "deletion" of separator character
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String oldValueText = oldValue.text.replaceAll(separator, '');
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String newValueText = newValue.text.replaceAll(separator, '');
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if (oldValue.text.endsWith(separator) &&
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oldValue.text.length == newValue.text.length + 1) {
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newValueText = newValueText.substring(0, newValueText.length - 1);
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}
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// Only process if the old value and new value are different
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if (oldValueText != newValueText) {
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int selectionIndex =
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newValue.text.length - newValue.selection.extentOffset;
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final chars = newValueText.split('');
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String newString = '';
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for (int i = chars.length - 1; i >= 0; i--) {
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if ((chars.length - 1 - i) % 3 == 0 && i != chars.length - 1) {
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newString = separator + newString;
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}
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newString = chars[i] + newString;
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}
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return TextEditingValue(
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text: newString.toString(),
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selection: TextSelection.collapsed(
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offset: newString.length - selectionIndex,
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),
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);
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}
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// If the new value and old value are the same, just return as-is
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return newValue;
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}
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}
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