我已经注册了Urban Airship，获得了应用程序密钥，密钥和主密钥。我也整合了他们的图书馆

-(void)setupUrbanAirship
{
    UAConfig *config = [UAConfig defaultConfig];
    config.detectProvisioningMode = YES;
    config.productionLogLevel=NO;
    config.inProduction = NO;
    config.developmentAppKey = @"XXXXXXXXXXXXXXXXXXX";
    config.developmentAppSecret = @"XXXXXXXXXXXXXXXXX";

    [UAirship takeOff:config];

    [UAirship push].userPushNotificationsEnabled = YES;

    [UAirship push].userNotificationTypes = (UIUserNotificationTypeAlert |
                                             UIUserNotificationTypeBadge |
                                             UIUserNotificationTypeSound);
}

我在我的代码中调用它：

NSString *channelID = [UAirship push].channelID;
NSLog(@"channelID %@",channelID);

在第一次运行应用程序期间，channelID始终为空。
我能够在第二次运行期间接收channelID，但在第一次运行期间无法接收。无论如何，可以建议应用程序在第一次运行期间获得channelID的方法。先谢谢你了。
编辑：
根据ralepinski的建议，我添加了'[UAirship push].registrationDelegate = self.registrationDelegate'代码行。
在ViewController.h中：

@interface ViewController : UIViewController
{
    IBOutlet UIButton *selectButton;
    NSTimer *channelIDDetectionTimer;
}
@property (nonatomic, weak, nullable) id<UARegistrationDelegate> registrationDelegate;

在ViewController.m中，我还使用了以下代码行：

-(void)initRegistration
{
    AppDelegate *delegate = [[UIApplication sharedApplication] delegate];

    NSString *channelID = [UAirship push].channelID;
    NSLog(@"channelID %@",channelID);
    if (channelID!=nil)
    {
        [delegate saveChannelID];
        if (channelIDDetectionTimer!=nil)
        {
            [channelIDDetectionTimer invalidate];
            channelIDDetectionTimer = nil;
        }
    }
    else
    {
        [UAirship push].registrationDelegate = self.registrationDelegate;
        //[[UAPush alloc]updateRegistration];
            // Registering for only UIRemoteNotificationTypeNone will not result in a
            // device token registration call. Instead update chanel registration directly.
    }
}

-(void)viewWillAppear:(BOOL)animated
{
    channelIDDetectionTimer = [NSTimer scheduledTimerWithTimeInterval:5.0 target:self selector:@selector(initRegistration) userInfo:nil repeats:YES];
}

我已经在应用程序目标的功能部分启用了远程通知。在应用程序第一次运行时，我仍然得到的ChannelID为null。告诉我谢谢