推送通知有效负载未保存在某些设备上

Question

我在处理某些设备上的通知有效负载时出现问题。我通过Parse Cloud功能向我的用户发送推送通知。

我使用下面的方法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，我通常会收到通知，并且它会正确保存在朋友的设备上，但通知是否到达，但是如果应用程序在后台，则不会保存有效内容，而如果应用程序处于前景，则会保存有效内容。

这可能是设备本身的问题吗？或者也许是与手机供应商有关的东西（我有h3g，他有沃达丰）？

-(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

我想这个问题是你如何处理应用程序的状态UIApplicationStateInactive。在这种情况下，您不存储信息。您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此状态。这也解释了为什么它有时会失败。 另请参阅this question，其中指出当设备收到通知时，该应用有时处于状态UIApplicationStateInactive。

你应该重构你的代码将数据存储在所有情况下：

-(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： 我不知道有关调用completionHandler(UIBackgroundFetchResultNoData)在applicationState（不知道这是好的），但也许您需要拨打completionHandler(UIBackgroundFetchResultNewData)来代替，在这种情况下，也需要存储数据。

此外，请确保您已正确配置所有内容，以便在后台接收通知，[请参阅此处]回答（https://stackoverflow.com/a/31450953/594074）。