您的客户端应用在安装到设备上后，就可以通过 FCM APNs 接口接收消息。您可以使用通知编辑器立即开始向细分用户群发送通知，或者您的应用服务器可以通过 APNs 接口发送带有通知有效负载的消息。
在大多数典型的使用情形中，都可能需要处理通过 FCM APNs 接口接收的消息。对于要求极高可靠性的特殊用例，您可以在应用中处理 FCM 直接通道消息。您还可以发送上行消息。
处理通过 FCM APNs 接口接收到的消息
当您的应用处于后台时，iOS 会将含有 notification 键的消息发送到系统托盘。用户点按一条通知即可打开该应用，系统会将通知的内容传递给 AppDelegate 中的 didReceiveRemoteNotification 回调函数。
按如下所示实现 AppDelegate application:didReceiveRemoteNotification:：
Swift
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any]) {
// If you are receiving a notification message while your app is in the background,
// this callback will not be fired till the user taps on the notification launching the application.
// TODO: Handle data of notification
// With swizzling disabled you must let Messaging know about the message, for Analytics
// Messaging.messaging().appDidReceiveMessage(userInfo)
// Print message ID.
if let messageID = userInfo[gcmMessageIDKey] {
print("Message ID: \(messageID)")
}
// Print full message.
print(userInfo)
}
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any],
fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
// If you are receiving a notification message while your app is in the background,
// this callback will not be fired till the user taps on the notification launching the application.
// TODO: Handle data of notification
// With swizzling disabled you must let Messaging know about the message, for Analytics
// Messaging.messaging().appDidReceiveMessage(userInfo)
// Print message ID.
if let messageID = userInfo[gcmMessageIDKey] {
print("Message ID: \(messageID)")
}
// Print full message.
print(userInfo)
completionHandler(UIBackgroundFetchResult.newData)
}
Objective-C
- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo {
// If you are receiving a notification message while your app is in the background,
// this callback will not be fired till the user taps on the notification launching the application.
// TODO: Handle data of notification
// With swizzling disabled you must let Messaging know about the message, for Analytics
// [[FIRMessaging messaging] appDidReceiveMessage:userInfo];
// Print message ID.
if (userInfo[kGCMMessageIDKey]) {
NSLog(@"Message ID: %@", userInfo[kGCMMessageIDKey]);
}
// Print full message.
NSLog(@"%@", userInfo);
}
- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {
// If you are receiving a notification message while your app is in the background,
// this callback will not be fired till the user taps on the notification launching the application.
// TODO: Handle data of notification
// With swizzling disabled you must let Messaging know about the message, for Analytics
// [[FIRMessaging messaging] appDidReceiveMessage:userInfo];
// Print message ID.
if (userInfo[kGCMMessageIDKey]) {
NSLog(@"Message ID: %@", userInfo[kGCMMessageIDKey]);
}
// Print full message.
NSLog(@"%@", userInfo);
completionHandler(UIBackgroundFetchResultNewData);
}
如果您希望打开应用并执行某项特定操作，请在通知负载中设置 click_action。使用的值应与您将在 APNs 有效负载的 category 键中使用的值相同。
解读通知消息有效负载
通知消息的有效负载是由键和值组成的字典。通过 APNs 发送的通知消息需要遵循如下 APNs 有效负载格式：
{
"aps" : {
"alert" : {
"body" : "great match!",
"title" : "Portugal vs. Denmark",
},
"badge" : 1,
},
"customKey" : "customValue"
}
在方法调配已停用的情况下处理消息
如果您停用了方法调配，则需要调用一个方法来让 FCM 跟踪消息传递和分析过程。如果您启用了方法调配，则系统会自动执行这一跟踪操作。
在 iOS 10 及更高版本中，您可以设置 UNUserNotificationCenter delegate 以接收来自 Apple 的显示通知，还可以设置 FIRMessaging 的 delegate 属性以接收来自 FCM 的数据消息。如果不使用 AppDelegate 设置这两个委托，则用于消息处理的方法调配会被停用。您需要调用 appDidReceiveMessage: 才能跟踪消息传递和分析过程。
Objective-C：iOS 10
// Receive displayed notifications for iOS 10 devices.
// Handle incoming notification messages while app is in the foreground.
- (void)userNotificationCenter:(UNUserNotificationCenter *)center
willPresentNotification:(UNNotification *)notification
withCompletionHandler:(void (^)(UNNotificationPresentationOptions))completionHandler {
NSDictionary *userInfo = notification.request.content.userInfo;
// With swizzling disabled you must let Messaging know about the message, for Analytics
// [[FIRMessaging messaging] appDidReceiveMessage:userInfo];
// Print message ID.
if (userInfo[kGCMMessageIDKey]) {
NSLog(@"Message ID: %@", userInfo[kGCMMessageIDKey]);
}
// Print full message.
NSLog(@"%@", userInfo);
// Change this to your preferred presentation option
completionHandler(UNNotificationPresentationOptionNone);
}
// Handle notification messages after display notification is tapped by the user.
- (void)userNotificationCenter:(UNUserNotificationCenter *)center
didReceiveNotificationResponse:(UNNotificationResponse *)response
withCompletionHandler:(void(^)(void))completionHandler {
NSDictionary *userInfo = response.notification.request.content.userInfo;
if (userInfo[kGCMMessageIDKey]) {
NSLog(@"Message ID: %@", userInfo[kGCMMessageIDKey]);
}
// Print full message.
NSLog(@"%@", userInfo);
completionHandler();
}
Objective-C：iOS 9 及更低版本
// With "FirebaseAppDelegateProxyEnabled": NO
- (void)application:(UIApplication *)application
didReceiveRemoteNotification:(NSDictionary *)userInfo
fetchCompletionHandler:
(void (^)(UIBackgroundFetchResult))completionHandler {
// Let FCM know about the message for analytics etc.
[[FIRMessaging messaging] appDidReceiveMessage:userInfo];
// handle your message.
}
Swift：iOS 10
@available(iOS 10, *)
extension AppDelegate : UNUserNotificationCenterDelegate {
// Receive displayed notifications for iOS 10 devices.
func userNotificationCenter(_ center: UNUserNotificationCenter,
willPresent notification: UNNotification,
withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
let userInfo = notification.request.content.userInfo
// With swizzling disabled you must let Messaging know about the message, for Analytics
// Messaging.messaging().appDidReceiveMessage(userInfo)
// Print message ID.
if let messageID = userInfo[gcmMessageIDKey] {
print("Message ID: \(messageID)")
}
// Print full message.
print(userInfo)
// Change this to your preferred presentation option
completionHandler([])
}
func userNotificationCenter(_ center: UNUserNotificationCenter,
didReceive response: UNNotificationResponse,
withCompletionHandler completionHandler: @escaping () -> Void) {
let userInfo = response.notification.request.content.userInfo
// Print message ID.
if let messageID = userInfo[gcmMessageIDKey] {
print("Message ID: \(messageID)")
}
// Print full message.
print(userInfo)
completionHandler()
}
}
Swift：iOS 9 及更低版本
func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject], fetchCompletionHandler completionHandler: (UIBackgroundFetchResult) -> Void) {
// Let FCM know about the message for analytics etc.
FIRMessaging.messaging().appDidReceiveMessage(userInfo)
// handle your message
}
处理 FCM 直接通道消息
要在应用于前台运行时直接从 FCM（绕过 APNs）可靠地接收仅包含数据的静默消息，您需要连接到 FCM 服务并使用 FIRMessagingDelegate 的 messaging:didReceiveMessage: 方法处理消息。启用直接通道后，当应用在后台运行或已关闭时，FCM 后端会使用可靠消息队列来跟踪待处理消息。当应用进入前台并重新建立连接时，该通道将自动向客户端发送待处理消息，直到它从客户端收到确认为止。
要进行连接，请在 AppDelegate 中将 shouldEstablishDirectChannel 标志设为 YES。FCM 会管理连接，在您的应用转到后台时断开连接，并在应用每次返回前台时重新建立连接。
另外，请在 AppDelegate 中将 useMessagingDelegateForDirectChannel 标志设置为 YES 并实现 messaging:didReceiveMessage:。无论是否有此回调函数，应用仍然可以接收 APNs 消息，但是对于来自 FCM 的直接消息，您就需要此回调函数。
解读数据消息有效负载
数据消息的有效负载是由键和值组成的字典。由 FCM 服务器直接发送到设备的数据消息采用如下所示的字典格式：
{
"body" : "great match!",
"title" : "Portugal vs. Denmark",
"icon" : "myicon"
}
处理已加入队列和已删除的消息
连接到 FCM 接收数据消息的应用应处理 FIRMessagingMessagesDeletedNotification。如果您在特定设备上的应用在该设备连接 FCM 时有过多的待处理消息（超过 100 条），或者该设备超过一个月未连接到 FCM，则您可能会收到此回调。当应用实例收到此回调时，应与您的应用服务器完全同步一次。
有关发送到您应用的消息的数据分析，请参阅 FCM 报告信息中心，该信息中心记录在 iOS 和 Android 设备上发送和打开的消息数量，以及 Android 应用的“展示次数”（用户看到的通知）数据。
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