我试图使用firebase云评估,在这个过程中,我想在推送通知到达时向用户显示一个弹出的对话。但是为了显示对话,我们需要将上下文对象作为参数之一。showDialog
是 BuildContext
.
我试过很多方法,但都没有用。目前,我的代码是这样的。
_firebaseMessaging.configure(
onMessage: (Map<String, dynamic> message) {
print('onMessage: $message');
return;
},
onBackgroundMessage: myBackgroundMessageHandler,
onResume: (Map<String, dynamic> message) {
print('onResume: $message');
return;
},
onLaunch: (Map<String, dynamic> message) {
print('onLaunch: $message');
Text('onLaunch: $message'),
);
return;
});
注: 这段代码是在一个单独的类中写的,我试图在没有任何第三部分库的情况下实现它。
首先,如果没有一个有效的上下文,你是无法显示对话框的。你为什么不简单地通过一个 BuildContext
到你的类中,就像这样?
class SeparateClass {
final BuildContext context;
SeparateClass(this.context);
void configure() {
// your rest of the configuration code
// you can use showDialog(context, ...) here
}
}
我解决了一个类似的问题,显示一个SnackBar而不是Dialog。有了这段代码,你可以在你的应用程序中任何地方启动一个SnackBar或Dialog。
import 'package:collectio/pages/init_screen_page.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'helper.dart';
void main() {
Provider.debugCheckInvalidValueType = null;
runApp(App());
}
class App extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
// here the context refers to MaterialApp widget,
// you can´t call Scaffold.of(context)
body: Builder(builder: (context) {
// here the context refers to Scaffold widget
Helper.startFirebaseMessaging(context);
return InitScreenPage();
}),
));
}
}
class Helper {
static startFirebaseMessaging(BuildContext buildContext) {
final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
_firebaseMessaging.configure(
onMessage: (Map<String, dynamic> message) async {
print("onMessage: $message");
var notification = message['notification'];
// build the snackbar
final snackBar = SnackBar(
content: Text(notification['title']),
action: SnackBarAction(
label: 'Ok',
onPressed: (){}
),
);
try {
Scaffold.of(buildContext).showSnackBar(snackBar);
} catch (e) {
print(e);
}
},
onLaunch: (Map<String, dynamic> message) async {
print("onLaunch: $message");
},
onResume: (Map<String, dynamic> message) async {
print("onResume: $message");
},
);
_firebaseMessaging.requestNotificationPermissions(
const IosNotificationSettings(
sound: true, badge: true, alert: true, provisional: true));
_firebaseMessaging.onIosSettingsRegistered
.listen((IosNotificationSettings settings) {
print("Settings registered: $settings");
});
_firebaseMessaging.getToken().then((String token) {
assert(token != null);
print("Push Messaging token: $token");;
});
print("Waiting for token...");
}
}
也许你可以把这个应用到你的代码中。