UserNotification 未显示（iOS 10）

Question

我无法在 iOS 10 中触发 UserNotification。我将从我的代码开始：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

//

UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
        UNAuthorizationOptions options = (UNAuthorizationOptionBadge | UNAuthorizationOptionAlert | UNAuthorizationOptionSound);

        center.delegate = self;

        [center requestAuthorizationWithOptions: options
                              completionHandler: ^(BOOL granted, NSError * _Nullable error) {
                                  if (granted) {
                                      NSLog(@"Granted notifications!");
                                  }
                              }];
//

这行得通，我看到了日志。

那么，我有：

-(void)application: (UIApplication *)application performFetchWithCompletionHandler: (void (^)(UIBackgroundFetchResult))completionHandler {
 //

UNMutableNotificationContent *content = [UNMutableNotificationContent new];
                content.title = NSLocalizedString(@"Updates are available", nil);

                UNTimeIntervalNotificationTrigger *trigger = [UNTimeIntervalNotificationTrigger triggerWithTimeInterval: 1
                                                                                                                repeats: NO];
                UNNotificationRequest *request = [UNNotificationRequest requestWithIdentifier: @"IDLocalNotification"
                                                                                      content: content
                                                                                      trigger: trigger];

                UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];

                [center addNotificationRequest: request withCompletionHandler: ^(NSError * _Nullable error) {
                    if (!error) {
                        NSLog(@"Notification was requested!");
                    }
                }];

再次，这有效，我看到了日志。

但我的屏幕上没有看到通知（触发延迟只有 1 秒，但我也尝试了更大的值）。

另外，willPresentNotification 委托方法永远不会到达。

我错过了什么？

Answer 1

发现问题。

原来我需要设置内容的body，而不仅仅是title：

UNMutableNotificationContent *content = [UNMutableNotificationContent new];
content.body = [NSString localizedUserNotificationStringForKey: @"Updates are available" arguments: nil];

我什至可以不用title 并且它可以工作。