推送通知有效负载未保存在某些设备上

Question

我在在某些设备上处理通知负载时遇到了问题。我正在通过 Parse Cloud 功能向我的用户发送推送通知。

我正在使用以下方法来捕获通知并存储其有效负载，以便用户可以在专用视图中查看所有收到的通知。在我的个人设备上，我总是收到通知并正确保存，在我朋友的设备上，虽然通知到达，但如果应用程序在后台，则不会保存有效负载，而如果应用程序在前台，有效负载会被保存。

这可能是设备本身的问题吗？或者可能与电话提供商有关（我有 h3g，他有 Vodafone）？

-(void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler{
// Parse push handler will show a UIAlertView
[PFPush handlePush:userInfo];

if (application.applicationState == UIApplicationStateInactive) {

    // tha app is inactive, transitioning to or from the background        
    completionHandler(UIBackgroundFetchResultNoData);

} else if (application.applicationState == UIApplicationStateBackground) {

    // tha app is running in background
    // add the notification to the notificationsArrayRecord
    NSDate *now = [[NSDate alloc]init];
    NSDictionary *aps = userInfo[@"aps"];
    NSString *alertMessage = aps[@"alert"];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

    NSMutableArray *notificationsArrayRecord = [[defaults arrayForKey:@"notificationsArrayRecord"] mutableCopy];
    [notificationsArrayRecord addObject:@[now,alertMessage]];
    [defaults setValue: notificationsArrayRecord forKey:@"notificationsArrayRecord"];

    // update the notifications counter
    NSInteger pushCount = [[NSUserDefaults standardUserDefaults] integerForKey: @"pushCount"];
    pushCount ++;
    [defaults setInteger: pushCount forKey:@"pushCount"];
    [defaults synchronize];

    completionHandler(UIBackgroundFetchResultNewData);
} else {        
    // the app is running in foreground

    // add the notification to the notificationsArrayRecord
    NSDate *now = [[NSDate alloc]init];
    NSDictionary *aps = userInfo[@"aps"];
    NSString *alertMessage = aps[@"alert"];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

    NSMutableArray *notificationsArrayRecord = [[defaults arrayForKey:@"notificationsArrayRecord"] mutableCopy];
    [notificationsArrayRecord addObject:@[now,alertMessage]];
    [defaults setValue: notificationsArrayRecord forKey:@"notificationsArrayRecord"];

    // update the notifications counter
    NSInteger pushCount = [[NSUserDefaults standardUserDefaults] integerForKey: @"pushCount"];
    pushCount ++;
    [defaults setInteger: pushCount forKey:@"pushCount"];
    [defaults synchronize];

    completionHandler(UIBackgroundFetchResultNewData);

    // refresh the menu buttons and the notification counter
    [[NSNotificationCenter defaultCenter] postNotificationName:@"appDidReceiveNotificationWhileActive" object:nil];
   }
  }

Answer 1

我想问题是你如何处理应用程序状态UIApplicationStateInactive。在这种情况下，您没有存储信息。您还应该在这种情况下存储它，因为当您收到通知时，应用程序显然可能处于这种状态。这也解释了为什么有时会失败。 另请参阅this question，它表明应用程序有时处于状态UIApplicationStateInactive，当设备收到通知时。

您应该重构代码以在所有情况下存储数据：

-(void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler{
    // Parse push handler will show a UIAlertView
    [PFPush handlePush:userInfo];

    // add the notification to the notificationsArrayRecord     
    NSDate *now = [[NSDate alloc]init];
    NSDictionary *aps = userInfo[@"aps"];
    NSString *alertMessage = aps[@"alert"];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

    NSMutableArray *notificationsArrayRecord = [[defaults arrayForKey:@"notificationsArrayRecord"] mutableCopy];
    [notificationsArrayRecord addObject:@[now,alertMessage]];
    [defaults setValue: notificationsArrayRecord forKey:@"notificationsArrayRecord"];

    // update the notifications counter
    NSInteger pushCount = [[NSUserDefaults standardUserDefaults] integerForKey: @"pushCount"];
    pushCount ++;
    [defaults setInteger: pushCount forKey:@"pushCount"];
    [defaults synchronize];

    if (application.applicationState == UIApplicationStateInactive) {
        // the app is inactive, transitioning to or from the background        
        completionHandler(UIBackgroundFetchResultNoData);
    } else if (application.applicationState == UIApplicationStateBackground) {
        // the app is running in background
        completionHandler(UIBackgroundFetchResultNewData);
    } else {        
        // the app is running in foreground
        completionHandler(UIBackgroundFetchResultNewData);

        // refresh the menu buttons and the notification counter
        [[NSNotificationCenter defaultCenter] postNotificationName:@"appDidReceiveNotificationWhileActive" object:nil];
    }
}

更新： 我不确定在applicationState 中调用completionHandler(UIBackgroundFetchResultNoData)（不知道这有什么用处），但也许您需要调用completionHandler(UIBackgroundFetchResultNewData)，同样在这种情况下，以获取存储的数据。

还要确保您正确配置了所有内容以在后台接收通知，[查看此]答案(https://stackoverflow.com/a/31450953/594074)。