iPhone在后台收集CoreMotion数据。 （超过10分钟）

Question

我正在尝试在后台收集coreMotion加速数据超过10分钟。这一定是可能的，因为像Sleep Cycle这样的应用就是这样做的。

我只是想确保允许这样做，因为它似乎不是其中之一：

Apps that play audible content to the user while in the background, such as a music player app
Apps that record audio content while in the background.
Apps that keep users informed of their location at all times, such as a navigation app
Apps that support Voice over Internet Protocol (VoIP)
Apps that need to download and process new content regularly
Apps that receive regular updates from external accessories
Apps that implement these services must declare the services they support and use system frameworks to implement the relevant aspects of those services. Declaring the services lets the system know which services you use, but in some cases it is the system frameworks that actually prevent your application from being suspended.

但是，我尝试按照这些步骤来完成后台任务，但我认为CoreMotion有更好的方法：

部首：

UIBackgroundTaskIdentifier bgTask; 

代码：

// if the iOS device allows background execution,
// this Handler will be called
- (void)backgroundHandler {

NSLog(@"### -->VOIP backgrounding callback");

UIApplication*    app = [UIApplication sharedApplication];

bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
    [app endBackgroundTask:bgTask];
    bgTask = UIBackgroundTaskInvalid;
}];

// Start the long-running task 
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

while (1) {
    NSLog(@"BGTime left: %f", [UIApplication sharedApplication].backgroundTimeRemaining);
       [self doSomething];
    sleep(1);
}   
});     

- (void)applicationDidEnterBackground:(UIApplication *)application {

BOOL backgroundAccepted = [[UIApplication sharedApplication] setKeepAliveTimeout:600 handler:^{ [self backgroundHandler]; }];
if (backgroundAccepted)
{
    NSLog(@"VOIP backgrounding accepted");
}

UIApplication*    app = [UIApplication sharedApplication];

bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
    [app endBackgroundTask:bgTask];
    bgTask = UIBackgroundTaskInvalid;
}];


// Start the long-running task
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

    while (1) {
        NSLog(@"BGTime left: %f", [UIApplication sharedApplication].backgroundTimeRemaining);
       [self doSomething];
       sleep(1);
    }    
}); 
}

Answer 1

使用这个：

Apps that keep users informed of their location at all times, such as a navigation app

换句话说，您创建了一个位置管理器并告诉它开始进行更新。您无需对这些更新执行任何操作！但只要这种情况发生 - 也就是说，只要您的应用继续在后台进行位置更新 - 您的应用也可以在后台使用Core Motion。这不仅仅是一招;这是几年前WWDC视频中解释的Apple官方政策。