如何从字符串创建 Flutter 小部件

Question

我想把一个实际上是内部小部件的字符串变成一个完整的工作小部件

String container = "Container(color:Colors.red)";

Widget magicFunction(String s){
  //Some wizards work 
}

Answer 1

您可以在下面复制粘贴运行完整代码
你可以使用包https://pub.dev/packages/dynamic_widget
例如https://github.com/dengyin2000/dynamic_widget/tree/master/example
这个包支持以下从String创建的Widget

容器、文本、TextSpan、TextStyle、RaisedButton、Row、...

代码sn-p

Future<Widget> _buildWidget(BuildContext context) async {
    return DynamicWidgetBuilder()
        .build(containerJson, context, new DefaultClickListener());
  }

Expanded(
          child: FutureBuilder<Widget>(
            future: _buildWidget(context),
            builder: (BuildContext context, AsyncSnapshot<Widget> snapshot) {
              if (snapshot.hasError) {
                print(snapshot.error);
              }
              return snapshot.hasData
                  ? SizedBox.expand(
                      child: snapshot.data,
                    )
                  : Text("Loading...");
            },
          ),
        ),

示例代码的工作演示

完整代码的工作演示

完整代码

import 'package:flutter/material.dart';
import 'package:dynamic_widget/dynamic_widget.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: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class DefaultClickListener implements ClickListener {
  @override
  void onClicked(String event) {
    print("Receive click event: " + event);
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  String containerJson = '''
{
  "type": "Container",
  "color": "#FF00FF",
  "alignment": "center",
  "child": {
    "type": "Text",
    "data": "Flutter dynamic widget",
    "maxLines": 3,
    "overflow": "ellipsis",
    "style": {
      "color": "#00FFFF",
      "fontSize": 20.0
    }
  }
}

''';

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  Future<Widget> _buildWidget(BuildContext context) async {
    return DynamicWidgetBuilder()
        .build(containerJson, context, new DefaultClickListener());
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Expanded(
              child: FutureBuilder<Widget>(
                future: _buildWidget(context),
                builder: (BuildContext context, AsyncSnapshot<Widget> snapshot) {
                  if (snapshot.hasError) {
                    print(snapshot.error);
                  }
                  return snapshot.hasData
                      ? SizedBox.expand(
                          child: snapshot.data,
                        )
                      : Text("Loading...");
                },
              ),
            ),
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}