Question

我正在制作一个需要身份验证和令牌检查的应用程序。如果用户没有令牌，则需要呈现 Auth 页面；如果令牌不存在，则需要呈现 Home 。

我正在使用//Declare the timer Timer t = new Timer(); //Set the schedule function and rate t.scheduleAtFixedRate(new TimerTask() { @Override public void run() { //Called each time when 1000 milliseconds (1 second) (the period parameter) // Get calendar set to the current date and time Calendar cal = Calendar.getInstance(); // ensures we're using the same current time Calendar cal2 = cal; // Set time of calendar to 22:00:00.000 cal.set(Calendar.HOUR_OF_DAY, 22); cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); cal.set(Calendar.MILLISECOND, 0); // Check if current time is after or before 22:00:00.000 today if ((cal2.after(cal)) || (cal2.before(cal)) { return; } PackageManager packageManager = context.getPackageManager(); Intent intent = new Intent(Intent.ACTION_VIEW); try { String url = "https://api.whatsapp.com/send?phone="+ toNumber +"&text=" + URLEncoder.encode(whatsAppMessage, "UTF-8"); intent.putExtra(Intent.EXTRA_TEXT, whatsAppMessage); intent.setType("text/plain"); intent.putExtra(Intent.EXTRA_STREAM, whatsAppImage); intent.setType("image/jpeg"); intent.setPackage("com.whatsapp"); intent.setData(Uri.parse(url)); startActivity(intent); } catch (Exception e){ e.printStackTrace(); } } }, //Set how long before to start calling the TimerTask (in milliseconds) 0, //Set the amount of time between each execution (in milliseconds) 1000);存储令牌。

颤振：1.5.4

flutter_secure_storage

我希望基于令牌获得import 'package:flutter/material.dart'; import 'package:flutter/services.dart'; import 'package:provider/provider.dart'; import 'package:myapp/api.dart'; import 'package:myapp/router.dart'; class App extends StatelessWidget { String _getInitialRoute(context) { final hasToken = Provider.of<API>(context).token != null; // Returns Future<String> instead of string return hasToken ? 'home' : 'auth'; } // build async is throwing here an error. build(context) { return MaterialApp( /** * Disable debug banner. */ debugShowCheckedModeBanner: false, /** * Initial route. */ initialRoute: _getInitialRoute(context), /** * Routes. */ onGenerateRoute: Router.generateRoute, /** * Application title. */ title: 'My App', ); } }。

Answer 1

您可以尝试

void main() async {
  String initialRoute = await SomethingHere(); // get your awaited string
  runApp(
    MaterialApp(
      initialRoute: initialRoute,
      onGenerateRoute: ...,
    ),
  );
}

Answer 2

尝试一下。

class MyApp extends StatelessWidget {
  MyApp();

  @override
  Widget build(BuildContext context) {
    return StoreProvider<AppState>(
      store: store,
      child: MaterialApp(
        title: 'Chaco Digital',
        debugShowCheckedModeBanner: false,
        onGenerateRoute: generateRoute,
        initialRoute: AUTH_HANDLER_ROUTE,
      ),
    );
  }
}

class AuthHandler extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new FutureBuilder(
              future: _storage.read(key: 'token'),
              builder: (_, AsyncSnapshot<bool> snapshot)
         => snapshot.hasData && snapshot.data ? HomePage() : SignInPage();
    );
  }
}

如何在没有等待的情况下获得未来价值？

2 个答案: