【发布时间】：2019-10-04 21:51:10
【问题描述】：
问题：3 种不同上下文中的不同行为
好的，好的，在 iOS 中，推送通知似乎会发生三种不同的事情：
- 当应用在前台不时收到推送通知
- 通知中心出现了一些东西
- 如果通过点击通知打开应用程序，会调用
AppDelegate.DidReceiveRemoteNotification(...)或AppDelegate.ReceivedRemoteNotification(...)，显然取决于实现的是哪一个(??)。 - 如果打开应用程序没有点击通知，只有
AppDelegate.WillEnterForeground(...)被调用，没有任何明确提及通知，并且没有别的碰巧承认这一点收到通知。
- 当应用程序在前台收到推送通知时，它会导致
UNUserNotificationCenterDelegate（如果有）执行UNUserNotificationCenterDelegate.WillPresentNotification(...)。李>
方法：从所有上下文路由到一个方法
因此，要使用 Push 覆盖所有基础，我需要在所有三种方法中实现一些东西：AppDelegate.DidReceiveRemoteNotification(...) / AppDelegate.ReceivedRemoteNotification(...)、AppDelegate.WillEnterForeground(...) 和 UNUserNotificationCenterDelegate .WillPresentNotification(...)。
这里有一些存根来展示我处理这一切的方法。
首先，我创建了一个自定义UNUserNotificationCenterDelegate，带有一个Shared 静态成员：
public class IncomingNotificationHandler : UNUserNotificationCenterDelegate
{
public static IncomingNotificationHandler Shared = new IncomingNotificationHandler();
...
}
其次，在该类中，我创建了一个处理程序，在每种情况下我都可以路由到该处理程序（再次强调，这只是一个用于调试目的的存根）：
//sets all parameters to null by default, so it can be called from methods
//that don't know anything about notifications:
public void HandleNotificationsIfAny(UIApplication application = null,
NSDictionary userInfo = null,
Action<UIBackgroundFetchResult> completionHandler = null)
{
//checks if userInfo is null, and logs its conclusions about that:
if (userInfo == null)
{
//In the null case, we can get pending notifications from
//UNUserNotificationCenter:
UNNotification[] pendingNotifications = new UNNotification[] { };
UNUserNotificationCenter.Current.GetDeliveredNotifications(returnedValue => pendingNotifications = returnedValue);
//Then we log the number of pending notifications:
Debug.WriteLine("IncomingNotificationHandler: HandleNotificationsIfAny(...): delivered notification count: " + pendingNotifications.Length);
//And make note of where this was probably called from:
Debug.WriteLine("IncomingNotificationHandler: HandleNotificationsIfAny(...): may have been called from this.WillPresentNotification(...) OR AppDelegate.WillEnterForeground(...)");
return;
});
}
else
{
//In the non-null case, we log the userInfo
Debug.WriteLine("IncomingNotificationHandler: HandleNotificationsIfAny(...): just got info: " + userInfo);
//And make note of where this was probably called from:
Debug.WriteLine("IncomingNotificationHandler: HandleNotificationsIfAny(...): may have been called from AppDelegate.DidReceiveRemoteNotification(...)");
}
}
第三，在同一个类中，我实现了UNUserNotificationCenterDelegate 所需的单个方法，并从中路由到处理程序：
public override void WillPresentNotification(UNUserNotificationCenter center, UNNotification notification, Action<UNNotificationPresentationOptions> completionHandler)
{
HandleNotificationsIfAny();
}
第四，也是最后，在AppDelegate 中，我从两个相关方法路由到同一个处理程序：
//I prefer using DidReceiveRemoteNotification because in my experience
//the other one is sometimes not reliable:
public override void DidReceiveRemoteNotification(UIApplication application,
NSDictionary userInfo,
Action<UIBackgroundFetchResult> completionHandler)
{
//Simply passing on all the parameters called in this method:
IncomingNotificationHandler.Shared.HandleNotificationsIfAny(application, userInfo, completionHandler);
}
//WillEnterForeground also calls the handler without any parameters
//because it doesn't automatically know anything about notifications:
public override void WillEnterForeground(UIApplication application)
{
IncomingNotificationHandler.Shared.HandleNotificationsIfAny();
}
就目前而言，我认为我正在以相同的方式处理通知事件，无论我的应用如何收到有关它的警报，即使它根本没有收到警报。
有谁知道我现在是否已经涵盖了它，或者我是否需要处理其他一些情况？
【问题讨论】：
标签： ios xamarin.forms push-notification