（Flutter）pub获取失败聊天取决于charts_flutter>=0.0.1+1=1.23.0

Question

大家好，新年快乐。

我是flutter和dart的初学者，每当我在pubspec.yaml依赖项中添加charts_flutter时，flutter就会出现问题。

我尝试运行Flutter clean，注意其他有此类问题的主题，并更改了Flutter SDK环境，但它不起作用。

import 'package:flutter/material.dart';
import 'package:charts_flutter/flutter.dart' as charts;
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
   return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
   MyHomePage({Key key, this.title}) : super(key: key);
   final String title;
   @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class ClicksPerYear {
   final String year;
   final int clicks;
   final charts.Color color;
   ClicksPerYear(this.year, this.clicks, Color color)
      : this.color = new charts.Color(r: color.red, g: color.green, b: color.blue, a: color.alpha);
}

class _MyHomePageState extends State<MyHomePage> {
   int _counter = 0;
   void _incrementCounter() {
   setState(() {
      _counter++;
    });
  }
   @override
   Widget build(BuildContext context) {
   var data = [
   new ClicksPerYear('2016', 12, Colors.red),
   new ClicksPerYear('2017', 42, Colors.yellow),
   new ClicksPerYear('2018', _counter, Colors.green),
    ];
   var series = [
   new charts.Series(
        domainFn: (ClicksPerYear clickData, _) => clickData.year,
        measureFn: (ClicksPerYear clickData, _) => clickData.clicks,
        colorFn: (ClicksPerYear clickData, _) => clickData.color,
        id: 'Clicks',
        data: data,
      ),
    ];
   var chart = new charts.BarChart<ClicksPerYear>(
      series,
      animate: true,
    );
   var chartWidget = new Padding(
      padding: new EdgeInsets.all(32.0),
      child: new SizedBox(
        height: 200.0,
        child: chart,
      ),
    );
   return new Scaffold(
      appBar: new AppBar(
        title: new Text(widget.title),
      ),
      body: new Center(
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
   new Text('You have pushed the button this many times:',
            ),
   new Text('$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
            chartWidget,
          ],
        ),
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: new Icon(Icons.add),
      ),
    );
  }
}

version: 1.0.0+1

environment:
  sdk: ">=2.1.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter
  charts_flutter: ^0.2.0


  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.2

dev_dependencies:
  flutter_test:
    sdk: flutter

在chat中运行“flutter pub get”...
当前Dart SDK版本为2.8.0-dev.0.0.flutter-aa6709974d。因为聊天依赖于charts_flutter>=0.0.1+1<0.4.0，这需要SDK版本>=1.23.0<2.0.0，所以版本解决失败。pub get失败（1；因为聊天依赖于charts_flutter>=0.0.1+1<0.4.0，这需要SDK版本>=1.23.0<2.0.0，所以版本解决失败。）退出代码1

Answer 1

哪里出了问题？

您添加的是charts_flutter插件的过时版本，它依赖于Flutter SDK的旧版本。

你能做什么？

charts_flutter: ^0.2.0

charts_flutter: ^0.8.1

environment:
  sdk: ">=2.1.0 <3.0.0"