Xcode 6.2 beta和iOS 8模拟器：位置管理器授权对话框无法出现：错误或无法理解？

Question

我找到了以下解决方案，解释了如何在iOS 8中使用定位服务。不幸的是，我只有一个iPhone 6模拟器，而没有真正的设备。 我试图将这段代码添加到viewDidLoad方法中，但从未显示授权对话框。 为什么是这样？

我在下面添加了一个断点，它被执行了，但没有显示出Dialouge ..：

    // Will open an confirm dialog to get user's approval
    [locationManager requestAlwaysAuthorization];

这是完整的viewDidLoad方法：

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // Initialize location manager
locationManager = [CLLocationManager new];
locationManager.delegate = self;

float system = [[[UIDevice currentDevice] systemVersion] floatValue ];

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0 &&
    [CLLocationManager authorizationStatus] != kCLAuthorizationStatusAuthorizedAlways
    ) {
    // Will open an confirm dialog to get user's approval
    [locationManager requestAlwaysAuthorization];
} else {
    [locationManager startUpdatingLocation]; //Will update location immediately
}
locationManager.desiredAccuracy = kCLLocationAccuracyBest;

PS：我还修改了info.plist，如下所示：

PPS：

这就是我在同一个ViewController中实现其余CLLocationManagerDelegate协议的方式 ：

#pragma mark - CLLocationManagerDelegate
- (void)locationManager:(CLLocationManager*)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{
    switch (status) {
        case kCLAuthorizationStatusNotDetermined: {
            NSLog(@"User still thinking..");
        } break;
        case kCLAuthorizationStatusDenied: {
            NSLog(@"User dislikes your app");
        } break;
        case kCLAuthorizationStatusAuthorizedWhenInUse:
        case kCLAuthorizationStatusAuthorizedAlways: {
            [locationManager startUpdatingLocation];
        } break;
        default:
            break;
    }
}

- (void)locationManager:(CLLocationManager *)manager
     didUpdateLocations:(NSArray *)locations {
    CLLocation *location = [locations lastObject];
    NSLog(@"lat%f - lon%f", location.coordinate.latitude, location.coordinate.longitude);
}

编辑2：我在答案中建议添加以下代码块。 该代码已执行，但对话未出现。

#pragma mark - CLLocationManagerDelegate
- (void)locationManager:(CLLocationManager*)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{
    switch (status) {
        case kCLAuthorizationStatusNotDetermined: {
            if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0){
                [locationManager requestAlwaysAuthorization];
            }
        } break;
        case kCLAuthorizationStatusDenied: {
            NSLog(@"User dislikes your app");
        } break;
        case kCLAuthorizationStatusAuthorizedWhenInUse:
        case kCLAuthorizationStatusAuthorizedAlways: {
            [locationManager startUpdatingLocation];
        } break;
        default:
            break;
    }
}

Answer 1

将此添加到didChangeAuthorizationStatus中：

case kCLAuthorizationStatusNotDetermined: {
    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)
        [locationManager requestAlwaysAuthorization];
    }

编辑

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0 &&
    [CLLocationManager authorizationStatus] != kCLAuthorizationStatusAuthorizedAlways
    ) {
    // Will open an confirm dialog to get user's approval
        [locationManager requestAlwaysAuthorization];
    }

    [locationManager startUpdatingLocation]; //Will update location immediately

Answer 2

我认为您的代码可能没有任何问题。 这是我正在使用的代码：-

    #define IS_OS_8_OR_LATER ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)

    if(IS_OS_8_OR_LATER) {
        [locationManager requestAlwaysAuthorization];
    }

    [locationManager startUpdatingLocation];

您可能不了解授权对话框的工作方式。 供您参考，授权对话框只会出现一次（您允许还是不允许）。 之后，您可以从“设置”中更改授权。

如果要重新显示授权对话框，则应从iPhone模拟器中删除该应用程序（长按该应用程序并点击X按钮）。 当您将应用程序从XCode重新启动到iPhone Simulator中时，只会重新显示授权对话框。