当应用程序处于后台时接收 Apple 推送通知

Question

我已经在我的 iOS8 应用中实现了推送通知。收到通知后，我正在尝试播放音频文件。

当应用程序在前台时，代码正在播放音频，但当应用程序在后台时，没有任何反应。

我已尝试重新生成证书和配置文件。而且我已确保该应用程序在后台运行，即用户没有向上滑动以将其删除。在后台模式下，我启用了远程通知、后台获取以及音频和 Airplay。

我从AppDelegate.m 文件中添加了代码 sn-ps：

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

// More code here ---------------------------------------------------
if (launchOptions) {
    NSDictionary *userInfo = [launchOptions valueForKey:UIApplicationLaunchOptionsRemoteNotificationKey];
    NSDictionary *apsInfo = [userInfo objectForKey:@"aps"];

    if (apsInfo) { //apsInfo is not nil
        [self performSelector:@selector(playCarAlarmAudio)
                   withObject:nil
                   afterDelay:1];
    }

}

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0) {
    [[UIApplication sharedApplication] registerForRemoteNotifications];
    UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:(UIUserNotificationTypeBadge
                                                                                         |UIUserNotificationTypeSound
                                                                                         |UIUserNotificationTypeAlert) categories:nil];

    [[UIApplication sharedApplication] registerUserNotificationSettings:settings];
}
// More code here ---------------------------------------------------
}

处理推送通知的委托方法：

-(void) application:(UIApplication *)application didFailToRegisterForRemoteNotificationsWithError:(NSError *)error {
NSLog(@"Failed to register for push");
}

-(void) application:(UIApplication *)application didRegisterUserNotificationSettings:(UIUserNotificationSettings *)notificationSettings {
}

-(void) application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo {
    [self respondToEventNotification:userInfo];
}

-(void) application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {

//    [self respondToEventNotification:userInfo];
    [self playAlarmAudio];

}

-(void) respondToEventNotification : (NSDictionary *) userInfo {
if ([[UIApplication sharedApplication] applicationState] == UIApplicationStateBackground) {
                UILocalNotification *localNotification = [[UILocalNotification alloc] init];
                [localNotification setSoundName:@"alarm.mp3"];
                [localNotification setFireDate:[NSDate date]];
                [[UIApplication sharedApplication] scheduleLocalNotification:localNotification];

            }
            else if ([[UIApplication sharedApplication] applicationState] == UIApplicationStateActive) {
                [self playAlarmAudio];
            }
}

然后播放闹钟：

-(void) playAlarmAudio {
    NSString *filePath = [[NSBundle mainBundle] pathForResource:@"alarm" ofType:@"mp3"];
    NSURL *fileUrl = [NSURL fileURLWithPath:filePath];
    self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:fileUrl error:nil];
    self.audioPlayer.numberOfLoops = 1;
    [self.audioPlayer play];
}

Answer 1

根据以下 Apple 文档，要播放的通知声音在通知负载字典 (https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html) 中指定：

通知负载

每个远程通知都包含一个有效负载。有效负载包含有关系统应如何提醒用户的信息以及您提供的任何自定义数据。在 iOS 8 及更高版本中，通知负载允许的最大大小为 2 KB； Apple Push Notification 服务拒绝任何超过此限制的通知。 （在 iOS 8 之前和 OS X 中，最大有效负载大小为 256 字节。）

对于每个通知，编写一个 JSON 字典对象（由 RFC 4627 定义）。该字典必须包含另一个由键 aps 标识的字典。 aps 字典可以包含一个或多个指定以下用户通知类型的属性：

• 向用户显示的警报消息
• 用于标记应用图标的数字
• 播放声音