极光后台推送响铃

前言：

本教程不讨论极光推送的集成，请自行百度如何集成极光推送
本教程适用于需要支持ios10以下的后台推送响铃
对于IOS以上的系统可以了解通知扩展（Notification Extension），一个非常强大的东西，本教程不介绍。
本教程的代码全部都放在AppDelegate.m文件里面

需求：

根据推送过来的内容，需要进行响铃提醒操作。即对于重要的推送要通过响铃要提醒用户。

思路介绍：

1.APP在前台，我们在接受通知的函数里面直接调用播放声音即可
2.APP在后台，我们需要先支持后台播放，之后让APP进入后台之后执行一个长期任务，让后台处于活跃状态，否则不会播放声音和语音播报
3.对于后台接受通知，会调用通知函数，当用户点击通知进入APP 会再调用一次通知函数，我们需要避免2次播放

步骤

1.配置Capabilities

image.png

image.png

2.支持后台播放

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

    [[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayback error: nil];
    [[AVAudioSession sharedInstance] setActive:YES error:nil];
    return YES;
}

3.后台保存活跃

//为了让后台接受推送时响铃 需要让app处于活跃状态
- (void)applicationDidEnterBackground:(UIApplication *)application {
    UIApplication* app = [UIApplication sharedApplication];
    __block    UIBackgroundTaskIdentifier bgTask;
    bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
        dispatch_async(dispatch_get_main_queue(), ^{
            if (bgTask != UIBackgroundTaskInvalid)
            {
                bgTask = UIBackgroundTaskInvalid;
            }
        });
    }];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        dispatch_async(dispatch_get_main_queue(), ^{
            if (bgTask != UIBackgroundTaskInvalid)
            {
                bgTask = UIBackgroundTaskInvalid;
            }
        });
    });
}

4.播放自定义的声音

//对于用户的定义的警告 要通过响铃
- (void)alarmClockEventWithHandler:(void (^)())completionHandler {
    AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
    
    if(!self.player) {
        NSString *filePath = [[NSBundle mainBundle] pathForResource:@"Thunder Song" ofType:@"m4r"];
        
        self.player = [[AVAudioPlayer alloc] initWithData:[NSData dataWithContentsOfFile:filePath] error:nil];
        
        self.player.numberOfLoops = -1;
        
        self.player.volume = 1.0;
    }
    
    [self.player stop];
    if([self.player prepareToPlay]) {
        [self.player play];
        completionHandler();
    }
}

5.推送处理函数

//收到推送信息  该API适用于IOS7以下的系统
- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo {
    [JPUSHService handleRemoteNotification:userInfo];
}
//收到推送信息 该API适用于IOS7以上的系统
- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {
    [JPUSHService handleRemoteNotification:userInfo];
    
    [self.player stop];
    __weak typeof(self)weakSelf = self;
    UIWindow *alertWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];

    alertWindow.rootViewController = [[UIViewController alloc] init];

    alertWindow.windowLevel = UIWindowLevelAlert + 1;

    [alertWindow makeKeyAndVisible];
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"提示" message:[NSString stringWithFormat:@"%@",userInfo[@"msg_content"]] preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"朕知道了" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        [weakSelf.player stop];
    }];
    [alertController addAction:okAction];
    //程序当前正处于前台收到apns通知
    if (application.applicationState == UIApplicationStateActive) {
      //通过 userInfo[@"_j_msgid"]]来避免用户点击进入APP两次响铃问题
        if([currentMsgId isEqualToString:userInfo[@"_j_msgid"]]) {
            [self.player stop];
            //用户点击了通知进入前台
            completionHandler(UIBackgroundFetchResultNewData);
        } else {
            //用户在前台没点通知
            currentMsgId = userInfo[@"_j_msgid"];
            [alertWindow.rootViewController presentViewController:alertController animated:YES completion:nil];
            [self alarmClockEventWithHandler:^{
                completionHandler(UIBackgroundFetchResultNewData);
            }];
        }
    } else {
        //这个userInfo就是jpush推送来的消息内容
        //后台通知事件
        currentMsgId = userInfo[@"_j_msgid"];
        [self alarmClockEventWithHandler:^{
            completionHandler(UIBackgroundFetchResultNewData);
        }];
    }
}