如何在颤动的任何屏幕上显示弹出消息？

Question

我需要在任何屏幕上显示一个带有消息的弹出窗口。它可以是教程/介绍屏幕、登录或主屏幕。基本上，弹出窗口会指示该应用程序是否有新的可下载版本。现在这没有任何条件。所以我应该能够在每次启动应用程序时向用户显示弹出消息。

同样是通过在 iOS 中的 didFinishLaunchingWithOptions 中添加弹出消息来实现的。我如何在颤振中做同样的事情？

Answer 1

弹出消息是通过flutter AlertDialog 小部件实现的。因此，如果您想在每次应用启动时提醒用户，您应该在应用启动的第一个屏幕中显示此小部件。这是文档中的一个示例：

// Flutter code sample for AlertDialog
//
// This demo shows a [TextButton] which when pressed, calls [showDialog]. When called, this method
// displays a Material dialog above the current contents of the app and returns
// a [Future] that completes when the dialog is dismissed.

import 'package:flutter/material.dart';

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

/// This is the main application widget.
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const Center(
          child: MyStatelessWidget(),
        ),
      ),
    );
  }
}

/// This is the stateless widget that the main application instantiates.
class MyStatelessWidget extends StatelessWidget {
  const MyStatelessWidget({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return TextButton(
      onPressed: () => showDialog<String>(
        context: context,
        builder: (BuildContext context) => AlertDialog(
          title: const Text('AlertDialog Title'),
          content: const Text('AlertDialog description'),
          actions: <Widget>[
            TextButton(
              onPressed: () => Navigator.pop(context, 'Cancel'),
              child: const Text('Cancel'),
            ),
            TextButton(
              onPressed: () => Navigator.pop(context, 'OK'),
              child: const Text('OK'),
            ),
          ],
        ),
      ),
      child: const Text('Show Dialog'),
    );
  }
}

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