有没有办法跟踪自 Flutter 中关闭对话消息以来的天数？

从 DateTime 类开始捕获对话框显示的时间

var now = new DateTime.now();

您可以使用具有调度功能的flutter_local_notifications。

var scheduledNotificationDateTime =
        new DateTime.now().add(new Duration(days: 30));
var androidPlatformChannelSpecifics =
    new AndroidNotificationDetails('your other channel id',
        'your other channel name', 'your other channel description');
var iOSPlatformChannelSpecifics =
    new IOSNotificationDetails();
NotificationDetails platformChannelSpecifics = new NotificationDetails(
    androidPlatformChannelSpecifics, iOSPlatformChannelSpecifics);
await flutterLocalNotificationsPlugin.schedule(
    0,
    'scheduled title',
    'scheduled body',
    scheduledNotificationDateTime,
    platformChannelSpecifics);