flutter - 为什么Android在iOS上不能在TextField中显示正确格式的文本？

Question

最小代码:

import 'package:intl/intl.dart';
import 'package:flutter/material.dart';

void main() => runApp(MaterialApp(home: MyPage()));

class MyPage extends StatelessWidget {
  final _controller = TextEditingController(text: "");

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Padding(
        padding: const EdgeInsets.all(44.0),
        child: Center(
          child: TextField(
            controller: _controller,
            keyboardType: TextInputType.number,
            onChanged: (string) {
              string = string.replaceAll(RegExp(","), "");
              string = _formattedString(string);
              _controller.text = string;
              _controller.selection = TextSelection.fromPosition(TextPosition(offset: string.length));
            },
          ),
        ),
      ),
    );
  }

   _formattedString(string) {
    final format = NumberFormat.decimalPattern();
    return format.format(int.parse(string));
  }
}

在Android和iOS上运行此代码，在android中输入类似 123456789的数字，它会打印出一些奇怪的序列，但在iOS上确实有效。谁能告诉我代码有什么问题吗？

Android输出



iOS输出

Answer 1

或者，如果您不希望项目中存在其他依赖项，请尝试以下方法:

import 'package:flutter/services.dart';
import 'package:intl/intl.dart';
import 'package:flutter/material.dart';

void main() => runApp(MaterialApp(home: MyPage()));

class NumericTextFormatter extends TextInputFormatter {
  TextEditingValue formatEditUpdate(
      TextEditingValue oldValue, TextEditingValue newValue) {
    if (newValue.text.length == 0) {
      return newValue.copyWith(text: '');
    } else if (newValue.text.compareTo(oldValue.text) != 0) {
      int selectionIndexFromTheRight = newValue.text.length - newValue.selection.end;
      final f = new NumberFormat("#,###");
      int num = int.parse(newValue.text.replaceAll(f.symbols.GROUP_SEP, ''));
      final newString = f.format(num);
      return new TextEditingValue(
        text: newString,
        selection: TextSelection.collapsed(offset: newString.length - selectionIndexFromTheRight),
      );
    } else {
      return newValue;
    }
  }
}

class MyPage extends StatelessWidget {
  final _controller = TextEditingController(text: "");

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Padding(
        padding: const EdgeInsets.all(44.0),
        child: Center(
          child: TextField(
            controller: _controller,
            keyboardType: TextInputType.number,
            inputFormatters: [NumericTextFormatter()],
          ),
        ),
      ),
    );
  }
}

信用归功于: https://stackoverflow.com/a/51739086/5235984