Question

打开应用程序时，本地通知应能正常工作。但是有些情况下，关闭申请后本地通知仍保留在通知中心中。然后单击通知将启动应用程序，并且通知数据应在 AppDelegate.FinishedLaunching 方法中的选项中传递。选项包含键 UIApplicationLaunchOptionsLocalNotificationKey ，其值类型为 UIKit.UILocalNotification 。此值包含UserInfo属性，该属性应填充通知数据。但是此UserInfo为null。

另一个问题是当本地通知保留在通知中心中并重新启动应用程序时。单击通知会导致应用程序再次启动，并立即停止。

您有这样的问题吗？ Xamarin是否有问题？如何处理这种情况？

创建通知

public void DisplayNotification(MessageInfo info)
{
    var notificationCenter = UNUserNotificationCenter.Current;

    var content = new UNMutableNotificationContent();
    content.Title = info.Title;
    content.Body = info.Body;
    content.UserInfo = IosStaticMethods.CreateNsDictFromMessageInfo(info);

    UNNotificationTrigger trigger;
    trigger = UNTimeIntervalNotificationTrigger.CreateTrigger(0.1, false);
    var id = (++_LastNotificationId).ToString();
    var request = UNNotificationRequest.FromIdentifier(id, content, trigger);

    notificationCenter.Delegate = new UserNotificationCenterDelegate();

    notificationCenter.AddNotificationRequest(request, (error) =>
    {
        //handle error
    });
}

internal class UserNotificationCenterDelegate : UNUserNotificationCenterDelegate
{
    public override void WillPresentNotification(UNUserNotificationCenter center, UNNotification notification, Action<UNNotificationPresentationOptions> completionHandler)
    {
        completionHandler(UNNotificationPresentationOptions.Alert);
    }

    public override void DidReceiveNotificationResponse(UNUserNotificationCenter center, UNNotificationResponse response, Action completionHandler)
    {
        //do something
    }
}

在AppDelegate.FinishedLaunching中处理通知

if (options != null)
{
    var notification = options["UIApplicationLaunchOptionsLocalNotificationKey"] as UIKit.UILocalNotification;
    var userInfo = notification.UserInfo;//the userInfo is null
}

Answer 1

似乎NSDictionary不应包含NSNull值。删除NSNull值后，即使NSDictionary文档https://developer.apple.com/documentation/foundation/nsdictionary说允许使用NSNull，一切正常。

Xamarin.IOS UILocalNotification.UserInfo在关闭应用程序后为null

1 个答案: