Flutter：在屏幕之间传递多个数据答案

【问题标题】：Flutter: Passing multiple data between screensFlutter：在屏幕之间传递多个数据
【发布时间】：2019-06-20 03:04:06
【问题描述】：

我是 Flutter 的新手。我正在尝试将多个数据发送到另一个屏幕：

// screen1.dart
..
Expanded(
  child: RaisedButton(
    onPressed: () {
      Navigator.push(context,
        MaterialPageRoute(
          builder: (context) => new Screen2(name: thing.name, email: thing.email, address: thing.address, etc..),
        ),
      );
    },
  ),
),
..


// screen2.dart

class Screen2 extends StatefulWidget{
  Screen2({this.name}, {this.email}, {this.address}, etc..);
  final String name;
  final String email;
  final String address;
  // etc
  @override
  State<StatefulWidget> createState() { return new Screen2State();}
}

class Screen2State extends State<Screen2> {
  Widget build(BuildContext context) {
    return new WillPopScope(
      ..
      child: Scaffold(
        ..
        new Row(
          children: <Widget>[
            new Text(widget.name),
            new Text(widget.email),
            new Text(widget.address),
            etc..
          ],
        ),
      )
    )
}

但我得到了错误：A non-null String must be provided to a Text widget.

数据是从 TextEditingControllers 传输的。当只有 1 个数据传输时它可以工作，但当有 2 个或更多数据时它会失败。

在屏幕之间发送多个数据的正确方法是什么？

【问题讨论】：

标签： flutter

【解决方案1】：

一切看起来都很好，但你需要在 Screen 2 类的构造函数中更改为这个

Screen2({this.name, this.email, this.address, etc..});

修改代码

// screen1.dart
..
Expanded(
  child: RaisedButton(
    onPressed: () {
      Navigator.push(context,
        MaterialPageRoute(
          builder: (context) => new Screen2(name: thing.name, email: thing.email, address: thing.address, etc..),
        ),
      );
    },
  ),
),
..


// screen2.dart

class Screen2 extends StatefulWidget{
 Screen2({this.name, this.email, this.address, etc..});
  final String name;
  final String email;
  final String address;
  // etc
  @override
  State<StatefulWidget> createState() { return new Screen2State();}
}

class Screen2State extends State<Screen2> {
  Widget build(BuildContext context) {
    return new WillPopScope(
      ..
      child: Scaffold(
        ..
        new Row(
          children: <Widget>[
            new Text(widget.name),
            new Text(widget.email),
            new Text(widget.address),
            etc..
          ],
        ),
      )
    )
}

注意：文本小部件不会接受空值，因此请确保您传递了所有值。或者你可以用默认值初始化变量为空白

final String name="";
final String email="";
final String address="";

【讨论】：

【解决方案2】：

考虑通过路由参数传递参数。参考官方文档https://flutter.dev/docs/cookbook/navigation/navigate-with-arguments

【讨论】：