29 lines
798 B
Dart
29 lines
798 B
Dart
import 'package:flutter/material.dart';
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import 'package:flutter/services.dart';
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class CardNumberInputFormatter extends TextInputFormatter {
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@override
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TextEditingValue formatEditUpdate(
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TextEditingValue oldValue, TextEditingValue newValue) {
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var text = newValue.text;
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if (newValue.selection.baseOffset == 0) {
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return newValue;
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}
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var buffer = new StringBuffer();
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for (int i = 0; i < text.length; i++) {
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buffer.write(text[i]);
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var nonZeroIndex = i + 1;
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if (nonZeroIndex % 4 == 0 && nonZeroIndex != text.length) {
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buffer.write(' '); // Add double spaces.
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}
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}
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var string = buffer.toString();
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return newValue.copyWith(
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text: string,
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selection: new TextSelection.collapsed(offset: string.length));
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}
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}
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