在我的应用程序中，我有一个名为“发现”的选项卡。发现选项卡将使用用户当前位置来查找他们附近的“东西”。我没有向用户展示一个通用的授权请求（根据研究通常会被拒绝），而是向用户展示了一个解释我们所要求的模式。如果他们说是，那么就会弹出实际的授权消息。
但是，用户仍然可以选择拒绝提示。有没有办法向提示添加回调，以便用户选择一个选项后，我可以查看他们是接受还是拒绝？
我试过这个：
func promptForLocationDataAccess() {
locationManager.requestWhenInUseAuthorization()
println("test")
}
正如所料，“println”在请求提示出现的同时执行，所以我不能那样做。
问题在于，如果用户选择不使用位置数据，则提供的内容将与他们接受时不同。
理想情况下，我希望得到某种回调，但此时我会采取任何合乎逻辑的方向！
【问题讨论】：
您可以使用
locationManager:didChangeAuthorizationStatus: CLLocationManagerDelegate 方法作为某种“回调”。
- (void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status {
if (status == kCLAuthorizationStatusDenied) {
// The user denied authorization
}
else if (status == kCLAuthorizationStatusAuthorized) {
// The user accepted authorization
}
}
在 Swift 中（用户 Michael Marvick 建议更新，但由于某种原因被拒绝...）：
func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
if (status == CLAuthorizationStatus.denied) {
// The user denied authorization
} else if (status == CLAuthorizationStatus.authorizedAlways) {
// The user accepted authorization
}
}
【讨论】：
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
if (status == CLAuthorizationStatus.denied) {
// The user denied authorization
} else if (status == CLAuthorizationStatus.authorizedAlways) {
// The user accepted authorization
}
}
【讨论】：
当位置的授权状态发生变化时，会调用委托方法didChangeAuthorizationStatus:。
当您在安装应用后第一次调用 requestWhenInUseAuthorization 时，委托方法将被调用，状态为 kCLAuthorizationStatusNotDetermined (0)。
如果用户拒绝位置服务访问，则委托方法将再次调用，状态为kCLAuthorizationStatusDenied (2)。
如果用户批准位置服务访问，则委托方法将再次调用，状态为 kCLAuthorizationStatusAuthorizedAlways (3) 或 kCLAuthorizationStatusAuthorizedWhenInUse (4)，具体取决于请求的权限。
在您的应用后续执行时，委托方法将根据设备设置中应用的当前位置服务权限状态调用requestWhenInUseAuthorization 后收到kCLAuthorizationStatusDenied 或kCLAuthorizationStatusAuthorizedAlways/kCLAuthorizationStatusAuthorizedWhenInUse 状态。
【讨论】：
这个解决方案并不是在所有情况下都是最好的，但它对我有用，所以我想我会分享：
import Foundation
import CoreLocation
class LocationManager: NSObject, CLLocationManagerDelegate {
static let sharedInstance = LocationManager()
private var locationManager = CLLocationManager()
private let operationQueue = OperationQueue()
override init(){
super.init()
//Pause the operation queue because
// we don't know if we have location permissions yet
operationQueue.isSuspended = true
locationManager.delegate = self
}
///When the user presses the allow/don't allow buttons on the popup dialogue
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
//If we're authorized to use location services, run all operations in the queue
// otherwise if we were denied access, cancel the operations
if(status == .authorizedAlways || status == .authorizedWhenInUse){
self.operationQueue.isSuspended = false
}else if(status == .denied){
self.operationQueue.cancelAllOperations()
}
}
///Checks the status of the location permission
/// and adds the callback block to the queue to run when finished checking
/// NOTE: Anything done in the UI should be enclosed in `DispatchQueue.main.async {}`
func runLocationBlock(callback: @escaping () -> ()){
//Get the current authorization status
let authState = CLLocationManager.authorizationStatus()
//If we have permissions, start executing the commands immediately
// otherwise request permission
if(authState == .authorizedAlways || authState == .authorizedWhenInUse){
self.operationQueue.isSuspended = false
}else{
//Request permission
locationManager.requestAlwaysAuthorization()
}
//Create a closure with the callback function so we can add it to the operationQueue
let block = { callback() }
//Add block to the queue to be executed asynchronously
self.operationQueue.addOperation(block)
}
}
现在每次你想使用位置信息时，只需用这个包围它：
LocationManager.sharedInstance.runLocationBlock {
//insert location code here
}
因此，每当您尝试使用位置信息时，都会检查授权状态。如果您还没有权限，它会请求权限并等待用户按下“允许”按钮或“不允许”按钮。如果按下“允许”按钮，任何位置数据请求都将在单独的线程上处理，但如果按下“不允许”按钮，则所有位置请求都将被取消。
【讨论】：
目标 C
对于 didChangeAuthorizationStatus 上的块回调，将其添加到 .h
@property void(^authorizationCompletionBlock)(BOOL);
并关注 .m
-(void)locationManager:(CLLocationManager *)locationManager didChangeAuthorizationStatus:(CLAuthorizationStatus)status {
_authorizationStatus = status;
switch (status) {
case kCLAuthorizationStatusAuthorizedAlways:
case kCLAuthorizationStatusAuthorizedWhenInUse:
if (self.authorizationCompletionBlock) {
self.authorizationCompletionBlock(YES); // this fires block
}
default:
if (self.authorizationCompletionBlock) {
self.authorizationCompletionBlock(NO); // this fires block
}
break;
}
}
并像这样添加处理程序：
// this listens block
// in your VC or Utility class
authorizationCompletionBlock = ^(BOOL isGranted) {
completionBlock(isGranted);
};
Swift 3.2
var authorizationCompletionBlock:((Bool)->())? = {_ in}
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
switch (status)
{
case (.authorizedWhenInUse):
if authorizationCompletionBlock != nil
{
authorizationCompletionBlock!(true)
}
default:
if authorizationCompletionBlock != nil
{
authorizationCompletionBlock!(false);
}
}
}
这样的处理程序
authorizationCompletionBlock = { isGranted in
print(isGranted)
}
【讨论】：
Swift 5 中的工作代码：
Plist：添加条目
<key>NSLocationWhenInUseUsageDescription</key>
<string>Needs Location when in use</string>
import UIKit
import CoreLocation
class ViewController: UIViewController {
var locationManager: CLLocationManager?
override func viewDidLoad() {
super.viewDidLoad()
locationManager = CLLocationManager()
//Make sure to set the delegate, to get the call back when the user taps Allow option
locationManager?.delegate = self
}
}
extension ViewController: CLLocationManagerDelegate {
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
switch status {
case .notDetermined:
print("not determined - hence ask for Permission")
manager.requestWhenInUseAuthorization()
case .restricted, .denied:
print("permission denied")
case .authorizedAlways, .authorizedWhenInUse:
print("Apple delegate gives the call back here once user taps Allow option, Make sure delegate is set to self")
}
}
}
【讨论】：
与上面 tdon 的响应类似，我创建了一个带有完成块的函数，用于在从设备检索到状态后传达状态：
func retrieveAuthorizationStatus(completion: @escaping (TrackingState) -> ()) {
let status = CLLocationManager.authorizationStatus()
switch status {
case .authorizedWhenInUse:
completion(.off)
default:
completion(.issue)
}
}
TrackingState 是一个单独的枚举，我用来管理视图控制器中的显示。您可以在完成块中轻松传递 authorizationStatus()：
func retrieveAuthorizationStatus(completion: @escaping (CLAuthorizationStatus) -> ()) {
let status = CLLocationManager.authorizationStatus()
completion(status)
}
【讨论】：