H5_Flutter/lib/view/component/rich_text.dart

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

// ignore: must_be_immutable
class LinkRichText extends StatefulWidget {
  double width;
  String text;
  LinkRichText({Key? key,required this.width,required this.text}) : super(key: key);

  @override
  State<LinkRichText> createState() => _LinkRichTextState();
}

class _LinkRichTextState extends State<LinkRichText> {
  bool mIsExpaned = false;
  int mSelectIndex = -1;
  bool isExpaned(String text, width) {
    TextPainter _textPainter = TextPainter(
        maxLines: 2,
        text: TextSpan(
            text: text, style: TextStyle(fontSize: 14.0, color: Colors.black)),
        textDirection: TextDirection.ltr)..layout(
          maxWidth: width-180,minWidth: 80
        );
      if (_textPainter.didExceedMaxLines){
        return true;
      }
      return false;
  }

  void _isShowText(){
    if (mIsExpaned){
      setState(() {
        mIsExpaned = false;
      });
    }
    else {
      setState(() {
        mIsExpaned = true;
      });
    }
  }

  // ignore: non_constant_identifier_names
  Widget _RichText(String _text,width){
    if (isExpaned(_text, width)){
      if (mIsExpaned){
        return Text.rich(
          TextSpan(
            text: _text,
            style: TextStyle(color: Colors.white,fontSize:14.0),
            children: [
              TextSpan(
                text: '收起',
                style: TextStyle(color: Colors.white),
                recognizer: TapGestureRecognizer()..onTap = ()async{
                  _isShowText();
                }
              )
            ]
          )
        );
      }
      else {
        return Stack(
          children: [
            Text(_text,style: TextStyle(color: Colors.white,fontSize: 14),
            maxLines: 2,textAlign: TextAlign.left,overflow: TextOverflow.ellipsis,),
            Positioned(bottom: 0,right: 0,child: GestureDetector(
              onTap: (){
                _isShowText();
              },
              child: Container(
                width: 50,
                child: Text('展开'),
              ),
            ))
          ],
        );
      }
    }
    else {
      return Text(
        _text,
        maxLines: 2,
        textAlign: TextAlign.left,
        overflow: TextOverflow.ellipsis,
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return _RichText(widget.text, widget.width);
  }
}