flutter - 如何创建扩展方法以对字符串进行颜色加粗，删除内容

Question

我有一个像这样的JSON:

[
  {
    "country": "UNITED STATED",
    "gini": 39,
    "note": "a country mostly located in central North America, between CANADA and MEXICO, It consists of 50 states. At 3.8 million square miles (9.8 million km2)"
  },
  {
    "country": "GERMANY",
    "gini": 33.1,
    "note": "Covering an area of 357,022 square kilometres (137,847 sq mi), it borders DENMARK to the north, POLAND to the east. "
  }
]

我要创建以下2个扩展方法:

对于“Gini”数据:删除“.0”(例如:“39.0” =>“39”)

对于“注释”数据:

粗体和颜色精确的文本“CANADA”； “墨西哥”; “丹麦”; “POLAND”

颜色所有数字

颜色“。”和“，”(如果介于数字

之间)



所以请帮助我，这是主要文件

import 'package:ask/services/us_services.dart';
import 'package:flutter/material.dart';
import 'model/us_model.dart';

class Demo2 extends StatefulWidget {
  Demo2() : super();

  @override
  _ContinentPageState createState() => _ContinentPageState();
}

class _ContinentPageState extends State<Demo2> {
  List<Zone> _zone = [];

  void initState() {
    super.initState();
    ContinentServices2.getContinent().then((zones) {
      setState(() {
        _zone = zones;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: Text('')),
        body: Column(crossAxisAlignment: CrossAxisAlignment.start, children: <Widget>[
          for (Zone zone in _zone)
            Padding(
                padding: const EdgeInsets.all(8.0),
                child: Table(columnWidths: {
                  0: FlexColumnWidth(0.2)
                },
                  children: [
                    TableRow(children: [TableCell(child: Text('Country ')), TableCell(child: Text(zone.country))]),
                    TableRow(children: [TableCell(child: Text('Gini')), TableCell(child: Text('${zone.gini}'))]),
                    TableRow(children: [TableCell(child: Text('Note')), TableCell(child: Text(zone.note))]),
                  ],
                ))
        ]));
  }
}

extension BoldColored on String {
  String get boldColored {}
}

extension Numbers on String {
  String get numbers {}
}

Answer 1

1。

这是您可以使用的扩展。它只会在小数点后修剪零。

extension DoubleExtension on double {
  String get asReadableString =>
      this % toInt() == 0 ? toInt().toString() : toString();
}

用法:

final value = 20.0;
print(value.asReadableString); // prints 20
final value2 = 20.5;
print(value2.asReadableString); // prints 20.5

2。

这是一个实用程序类，可用于格式化文本。

class RichTextFormatter {
  final Map<RegExp, TextStyle> patternMap;
  final TextStyle normalStyle;

  RichTextFormatter({
    @required this.patternMap,
    @required this.normalStyle,
  });

  TextSpan buildFormattedTextSpan(String text) {
    final children = <TextSpan>[];
    RegExp allRegex;
    allRegex = RegExp(patternMap.keys.map((e) => e.pattern).join('|'));
    text.splitMapJoin(
      allRegex,
      onMatch: (match) {
        final key = patternMap.entries
            .singleWhere(
                (element) => element.key.allMatches(match[0]).isNotEmpty)
            .key;
        children.add(TextSpan(text: match[0], style: patternMap[key]));
      },
      onNonMatch: (span) {
        children.add(TextSpan(text: span, style: normalStyle));
      },
    );
    return TextSpan(style: normalStyle, children: children);
  }
}

用法:

final formatter = RichTextFormatter(
  normalStyle: TextStyle(color: Colors.black),
  patternMap: {
    RegExp(r'CANADA|MEXICO|DENMARK|POLAND'):
        TextStyle(color: Colors.red, fontWeight: FontWeight.bold),
    RegExp(r'\d+(.\d+)?'):
        TextStyle(color: Colors.orange),
  },
);
final textSpan = formatter.buildFormattedTextSpan(text);

用户界面:

Text.rich(textSpan)