NSTimeInterval 到 unix 时间戳

问题描述

我从 CMMotionManager 获取 CMDeviceMotion 对象.CMDeviceMotion 的属性之一是时间戳，它表示为 NSTimeInterval (double).根据文档，这允许亚毫秒"时间戳精度.

I'm getting CMDeviceMotion objects from CMMotionManager. One of the properties of the CMDeviceMotion is timestamp, which is expressed as a NSTimeInterval (double). This allows for "sub millisecond" timestamp precision, according to documentation.

[motionManager startDeviceMotionUpdatesToQueue:motionQueue withHandler:^(CMDeviceMotion *motion, NSError *error) { 
  NSLog(@"Sample: %d Timestamp: %f ",counter,  motion.timestamp);
}

不幸的是，NSTimeInterval 是自上次设备启动后计算的，这给以原始形式使用它带来了重大挑战.

Unfortunately, NSTimeInterval is calculated since last device boot, posing significant challenges to using it in its raw form.

有没有人有工作代码可以将此 NSTimeInterval 转换为类似 Unix 的时间戳(UTC 时区)?

Does anyone have a working code to convert this NSTimeInterval into a Unix like timestamp (UTC timezone)?

谢谢！

推荐答案

在将磁力计值与 CoreMotion 事件进行比较时，我遇到了类似的问题.如果你想转换这些 NSTimeIntervals 你只需要计算一次偏移量:

I had a similar problem when comparing magnetometer values with CoreMotion events. If you want to transform these NSTimeIntervals you just need to calculate the offset once:

// during initialisation

// Get NSTimeInterval of uptime i.e. the delta: now - bootTime
NSTimeInterval uptime = [NSProcessInfo processInfo].systemUptime;

// Now since 1970
NSTimeInterval nowTimeIntervalSince1970 = [[NSDate date] timeIntervalSince1970];

// Voila our offset
self.offset = nowTimeIntervalSince1970 - uptime;