问题
I have read CLLocationManager kCLErrorDomain Codes? as well as Apple Docs
I check to make sure ranging is available before calling startRangingBeaconsInRegion: and I am also checking if ranging is available while in the locationManager:rangingBeaconsDidFailForRegion:withError: method. Returns true both times.
When I get the set of monitoredRegions, my beacon is in the set (so registering for monitoring is working).
I have read that error 16 can mean ranging is unavailable, bluetooth could be off, location services could be off, airplane mode could be on, I have checked them all and all are available and running (obviously not in airplane mode).
What could be causing the ranging to fail, every time I run the app?
回答1:
Just to eliminate any possibility that it could be something in your code, try a reference app like my Locate for iBeacon. If it also does not work, you probably have an OS or hardware problem.
To troubleshoot this, first reboot your phone and try again. Then try pairing to a regular Bluetooth device (headphones, Mac, etc). If regular Bluetooth pairing works, it may be a Bluetooth LE issue.
Your iOS device must be either an iPhone 4s+ or an iPad 3+ (needed for BLE).
回答2:
It seems that I started to face this issue after I updated my device to iOS 7.1 (iPhone 5S). rangingBeaconsDidFailForRegion: gets called with error.domain equal to @"kCLErrorDomain" and with error.code as kCLErrorRangingUnavailable (16) (even though Airplane mode is not on and Bluetooth is up and running).
I followed davidgyoung's advice to just boot (I did a hard boot pressing Home + Power until the device shuts down and displays the Apple logo, but also a normal boot works) the device, and now it seems to work correctly.
This appears to be a bug in iOS 7.1 and iOS 7.1.1, see here https://stackoverflow.com/a/22949187/1461050. The only workaround - for now - is to reboot the device.
Apple has now released iOS 7.1.2, which should fix this problem (awaiting for confirmation).
回答3:
The problem is closely related to the CoreBluetooth Unknown Error 1309.
In some circumstance, seems that the CoreBluetooth Stack become corrupted and the only solution is to reboot the device.
There're plenty of users that are reporting such behaviour. We've fired a bug to Apple Radar and we're waiting for response.
You can also report the problem to Apple Radar so that they will notice this bug.
来源：https://stackoverflow.com/questions/20905843/locationmanagerrangingbeaconsdidfailforregionwitherror-kclerrordomain-16