【发布时间】：2015-08-07 19:59:00
【问题描述】：
我正在开发一个将 iBeacons 与 CLLocation 和浅蓝色 bean ios sdks 一起使用的应用程序。如果我在没有信标的电池的情况下运行该应用程序，则该应用程序运行良好。如果我随后将电池插入信标，则应用程序会检测到信标并且运行良好。问题是当我从信标中取出电池时（或者当没有检测到信标或信标超出范围时）应用程序崩溃并给我以下错误，
致命错误：数组索引超出范围。
我了解此错误来自 CLLocationManagerDelegate 方法 didRangeBeacons，但我不确定如何防止我的应用程序崩溃？我的代码如下，
func locationManager(manager: CLLocationManager!, didRangeBeacons beacons: [AnyObject]!, inRegion region: CLBeaconRegion!) {
self.listBeans = beacons;
NSNotificationCenter.defaultCenter().postNotificationName("updateBeaconTableView", object: self.listBeans)
if beacons.count == 0{
println("no beacons nearby")
manager.stopUpdatingLocation()
manager.stopMonitoringForRegion(lightBlueRegion)
}else{
let knownBeacons = beacons.filter{$0.proximity != CLProximity.Unknown} // Proximity = 0
let closestBeacon = knownBeacons[0] as! CLBeacon
if(closestBeacon.proximity == lastProximity ||
closestBeacon.proximity == CLProximity.Unknown) {
return;
}
lastProximity = closestBeacon.proximity;
if (knownBeacons.count > 0){
switch closestBeacon.proximity {
case CLProximity.Far:
println("You are far away from the beacon")
case CLProximity.Near:
println("You are near the beacon")
case CLProximity.Immediate:
println("You are in the immediate proximity of the beacon")
case CLProximity.Unknown:
println("The proximity of the beacon is Unknown")
}
} else {
println("No beacons are nearby")
}
}
}
func locationManager(manager: CLLocationManager!, didEnterRegion region: CLRegion!) {
/* detected every one second */
println("Region discovered")
var enteredRegion = true
}
func locationManager(manager: CLLocationManager!, didExitRegion region: CLRegion!) {
var enteredRegion = false
}
func locationManager(manager: CLLocationManager!, didDetermineState state: CLRegionState, forRegion region: CLRegion!) {
switch state {
case CLRegionState.Inside:
/* In the .Inside case first notification is
displayed when the user is inside the region
and opens an app.
Second notification is shown when the app is in background
and the user enters the region*/
if enteredRegion == true{
message = "didDetermineState = INSIDE a region"
}
sendLocalNotificationWithMessage(message)
case CLRegionState.Outside:
/* Similar logic follows the .Outside case. It should be noted that the further you are from the beacons the longer it will take for the signal to propagate which means it may take few seconds for the notifications to be displayed when you leave or enter the region.*/
if enteredRegion == false{
message = "didDetermineState = OUTSIDE a region"
}
sendLocalNotificationWithMessage(message)
case CLRegionState.Unknown:
sendLocalNotificationWithMessage("didDetermineState = unknown Region")
default:
break;
}
}
func beanManagerDidUpdateState(beanManager: PTDBeanManager!) {
switch beanManager.state {
case .Unsupported:
var unsupportedAlert = UIAlertController(title: "Error", message: "This device is unsupported.", preferredStyle: UIAlertControllerStyle.Alert)
unsupportedAlert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(unsupportedAlert, animated: true, completion: nil)
case .PoweredOff:
var PpoweredOffAlert = UIAlertController(title: "Error", message: "Please turn on Bluetooth.", preferredStyle: UIAlertControllerStyle.Alert)
PpoweredOffAlert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(PpoweredOffAlert, animated: true, completion: nil)
case .PoweredOn:
beanManager.startScanningForBeans_error(nil);
default:
break
}
}
func beanManager(beanManager: PTDBeanManager!, didDiscoverBean bean: PTDBean!, error: NSError!) {
self.beanName = bean.name as String
self.beanUUIDNum = bean.identifier.description
}
谢谢
更新：
我最终得到了以下代码，
let knownBeacons:AnyObject? = beacons.filter{$0.proximity != CLProximity.Unknown} // Proximity = 0
if let knownBeacons_:AnyObject = knownBeacons {
if knownBeacons_.count == 0 {
return
}
if let closestBeacon = knownBeacons_[0] as? CLBeacon{
if(closestBeacon.proximity == lastProximity ||
closestBeacon.proximity == CLProximity.Unknown) {
return;
}
lastProximity = closestBeacon.proximity;
if (knownBeacons_.count > 0){
switch closestBeacon.proximity {
case CLProximity.Far:
println("You are far away from the beacon")
case CLProximity.Near:
println("You are near the beacon")
case CLProximity.Immediate:
println("You are in the immediate proximity of the beacon")
case CLProximity.Unknown:
println("The proximity of the beacon is Unknown")
}
} else {
println("No beacons are nearby")
}
}else{
println("no beacons nearby")
manager.stopUpdatingLocation()
manager.stopMonitoringForRegion(lightBlueRegion)
}
}
【问题讨论】：
标签： ios swift cllocationmanager ibeacon