flutter - 假设小部件的宽度从字符串中间切出文本

Question

在Dart中，我想知道如何从String的中间剪切文本？如我们所知，我们可以使用TextOverflow.ellipsis来减少字符串的结尾，但是我想拥有什么呢？

我想从字符串的中间剪切文本，例如我的字符串是:
Lorem ipsum dolor sit amet, consectetur adipiscing elit,
我应该如何从中间剪裁而假定小部件的宽度为:
Lorem i...ng elit,
要么
Lorem ipsum d...ur adipiscing elit,
我找不到有关此实现的任何示例代码或文档

Answer 1

这是一个简单但有点棘手的解决方案，不是最好的解决方案，但可以帮上忙。

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

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        body: SafeArea(
          child: MyHomePage(),
        ),
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Container(
      width: 300,
      child: TextWithCut(
          'Lorem ipsum dolor sit amet, consectetur adipiscing elit,'),
    );
  }
}

class TextWithCut extends StatelessWidget {
  const TextWithCut(this.text, {Key key, this.style}) : super(key: key);

  final String text;
  final TextStyle style;

  @override
  Widget build(BuildContext context) {
    var style = this.style ?? Theme.of(context).textTheme.body1;

    // not the perfect solution to find the symbol width:
    // a bold font is wider and some symbols are wider than normal
    var symbolWidth = style.fontSize * 0.6;

    return LayoutBuilder(
      builder: (context, constraints) {
        var numberOfElements = (constraints.maxWidth / symbolWidth).floor();

        return Text(middleCut(text, numberOfElements), style: style);
      },
    );
  }

  String middleCut(String text, int length) {
    const numberOfDots = 3;
    var dotsString = List<String>.filled(numberOfDots, '.').join();

    var leftSizeLengh = ((length - numberOfDots) / 2).floor();
    var rightSizeLength = text.length - leftSizeLengh;
    var leftPart = text.substring(0, leftSizeLengh);
    var rightPart = text.substring(rightSizeLength);
    return '$leftPart$dotsString$rightPart';
  }
}