如何在flutter中允许浮动通知和锁屏通知编程

dependencies:
  flutter_local_notifications: ^5.0.0

import 'package:flutter_local_notifications/flutter_local_notifications.dart';

FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
    FlutterLocalNotificationsPlugin();

const AndroidInitializationSettings initializationSettingsAndroid =
    AndroidInitializationSettings('app_icon');

final InitializationSettings initializationSettings =
    InitializationSettings(android: initializationSettingsAndroid);

await flutterLocalNotificationsPlugin.initialize(initializationSettings);

const AndroidNotificationDetails androidPlatformChannelSpecifics =
    AndroidNotificationDetails(
        'your channel id', 'your channel name', 'your channel description',
        importance: Importance.max, priority: Priority.high);

const NotificationDetails platformChannelSpecifics =
    NotificationDetails(android: androidPlatformChannelSpecifics);

await flutterLocalNotificationsPlugin.show(
    0, 'Notification Title', 'Notification Body', platformChannelSpecifics,
    payload: 'item x');