本地通知不會觸發後臺抓取

Question

有人可以看看下面的代碼，並告訴我爲什麼本地通知不會觸發。我在XCode中運行應用程序，並使用調試選項來模擬後臺獲取，但本地通知不會觸發。

- (void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler 
{ 
    NSLog(@"performFetchWithCompletionHandler"); 


UILocalNotification *localNotif = [[UILocalNotification alloc] init]; 

if (localNotif) { 
    localNotif.alertBody = @"Update demo text!"; 
    localNotif.alertAction = @"OK"; 
    localNotif.soundName = UILocalNotificationDefaultSoundName; 
    localNotif.fireDate = nil; 

    NSLog(@"Local Notification"); 

    [[UIApplication sharedApplication] scheduleLocalNotification:localNotif]; 
} 

//Perform some operation 
completionHandler(UIBackgroundFetchResultNewData); 
} 

Answer 1

您是否詢問用戶是否允許推送？

if ([UIDevice currentDevice].systemVersion.floatValue >= 8.0) { 
     UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeBadge | UIUserNotificationTypeAlert | UIUserNotificationTypeSound categories:nil]; 
     [application registerUserNotificationSettings:settings]; 
    } 

Answer 2

而不是檢查設備的版本，使用低於檢查RespondToSelector代碼：

if ([UIApplication instancesRespondToSelector:@selector(registerUserNotificationSettings:)]) 
{ 
    [application registerUserNotificationSettings:[UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeAlert|UIUserNotificationTypeBadge|UIUserNotificationTypeSound categories:nil]]; 
}