为什么纬度和经度在 ios 9 中显示为零？

Question

我必须找到当前位置，我正在使用此代码

 -(CLLocationCoordinate2D) getLocation{
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.distanceFilter = kCLDistanceFilterNone;
[locationManager startUpdatingLocation];
CLLocation *location = [locationManager location];
CLLocationCoordinate2D coordinate = [location coordinate];
return coordinate;

}

- (void)getCurrentLocation{
    CLLocationCoordinate2D coordinate = [self getLocation];
    NSString *latitude = [NSString stringWithFormat:@"%f", coordinate.latitude];
    NSString *longitude = [NSString stringWithFormat:@"%f", coordinate.longitude];
    NSLog(@"Latitude  = %@", latitude);
    NSLog(@"Longitude = %@", longitude);
}

但是纬度和经度要归零了？我在viewDidLoad中调用了这些方法

[self getCurrentLocation];
[self getLocation];

为什么会这样，请帮助我。谢谢

Answer 1

希望以下信息对您有所帮助：

 #import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>

@interface yourController : UIViewController <CLLocationManagerDelegate> {
    CLLocationManager *locationManager;
}

@end

并添加：

    locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)
    [self.locationManager requestWhenInUseAuthorization];

[locationManager startUpdatingLocation];

回调函数

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
NSLog(@"OldLocation %f %f", oldLocation.coordinate.latitude, oldLocation.coordinate.longitude);
NSLog(@"NewLocation %f %f", newLocation.coordinate.latitude, newLocation.coordinate.longitude);
}

您还必须为

添加一个字符串

[`NSLocationAlwaysUsageDescription`]

Answer 2

您需要使用“CLLocationManagerDelegate”。

只需阅读本教程。 How To Get the User Location in iPhone App

在这里您将了解CoreLocation Framework。

这是返回当前纬度的委托方法。

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation

还要确保您的应用授权使用位置服务。

并且还在设备上运行您的应用，或者如果您想在模拟器中查看结果，请按照教程中提到的步骤操作。

第 1 步：#import <CoreLocation/CoreLocation.h> 导入框架。还要在您的项目中添加框架。

第 2 步：确保您的视图控制器实现 CLLocationManagerDelegate

@interface MyLocationViewController : UIViewController <CLLocationManagerDelegate>

第三步：定义CLLocationManager的类实例

@implementation MyLocationViewController {
    CLLocationManager *locationManager;
}

第 4 步：

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    locationManager = [[CLLocationManager alloc] init];

    if([locationManager respondsToSelector:@selector(requestAlwaysAuthorization)]) {
            //iOS 8.0 onwards
            [locationManager requestAlwaysAuthorization];
        }
    locationManager.delegate = self;
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;

    [locationManager startUpdatingLocation];
}

第 5 步：这是您的 CLLocationManagerDelegate 方法实现

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    NSLog(@"didFailWithError: %@", error);
    UIAlertView *errorAlert = [[UIAlertView alloc]
                                    initWithTitle:@"Error" message:@"Failed to Get Your Location" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [errorAlert show];
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    NSLog(@"didUpdateToLocation: %@", newLocation);
    CLLocation *currentLocation = newLocation;

    if (currentLocation != nil) {
       NSLog(@"Longitude %.8f",currentLocation.coordinate.longitude);
       NSLog(@"Latitude %.8f",currentLocation.coordinate.latitude);
    }
}

Answer 3

首先转到您的 info.plist 并右键单击它并选择源代码选项。

然后在<dict>关键字后面加上以下几行

    <key>NSLocationAlwaysUsageDescription</key>
    <string>This App wants to Know your location</string>
    <key>NSLocationWhenInUseUsageDescription</key>
    <string>This App wants to Know your location</string>

没有这个，您将无法在 iOS 9.0 中使用 CLLocation。

现在按照说明进行操作。

导入

#import <CoreLocation/CoreLocation.h>

并列出类似的 CoreLocation 委托

@interface ViewController ()<CLLocationManagerDelegate>

@property (strong, nonatomic) CLLocationManager *locationManager;

@end

然后在 viewDidLoad 方法中添加以下几行-

    self.locationManager = [[CLLocationManager alloc]init];
    self.locationManager.delegate=self;
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;

    if ([self.locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]){
        [self.locationManager requestWhenInUseAuthorization];
    }
    [self.locationManager startUpdatingLocation];

现在实现委托方法

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    NSLog(@"didFailWithError: %@", error);
    UIAlertView *errorAlert = [[UIAlertView alloc]
                               initWithTitle:@"Sorry" 
                               message:@"Failed to Get Your Location"      
                               delegate:nil 
                               cancelButtonTitle:@"OK"  
                               otherButtonTitles:nil];
    [errorAlert show];
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    NSLog(@"didUpdateToLocation: %@", newLocation);
    CLLocation *currentLocation = newLocation;

    if (currentLocation != nil) {
        NSLog(@"%@", [NSString stringWithFormat:@"%.4f", currentLocation.coordinate.longitude]);
        NSLog(@"%@", [NSString stringWithFormat:@"%.4f", currentLocation.coordinate.latitude]);
    }
}

Answer 4

CLLocationManager 需要一些时间才能获得coordinates。因此，CLLocationManager 使用委托来通知它何时收到位置更新。因此，您无法立即获得结果。请查看this 的帖子，看看它是如何完成的。

Answer 5

好吧，我希望您阅读doc，但我仍在发布解决方案。

-(void)viewDidLoad{
     [self initLocationManager];
}


-(void)initLocationManager{

    self.locationManager=[[CLLocationManager alloc] init];
    self.locationManager.delegate=self;
    if (([_locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)])) {
        [_locationManager requestWhenInUseAuthorization];
    }
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    self.locationManager.distanceFilter = kCLDistanceFilterNone;
    [self.locationManager startUpdatingLocation];

}

然后在CLLocationManager 委托方法中处理位置更新，如下所示

-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray<CLLocation *> *)locations{

    // If it's a relatively recent event, turn off updates to save power.
    CLLocation* location = [locations lastObject];
    NSDate* eventDate = location.timestamp;
    NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
    if (abs(howRecent) < 15.0) {


        NSLog(@"%f,%f",location.coordinate.latitude,location.coordinate.longitude);


    }
}

更新

要让它发挥作用，你需要做两件事

1. 从Capabilities选项卡启用Background Modes，然后选择Location Updates，见下图

2. 在信息选项卡中添加NSLocationWhenInUseUsageDescription，到plist中，见图

它将开始工作。

希望对您有所帮助。干杯。

Answer 6

使用这个代码就可以了

首先在info.plist中添加NSLocationAlwaysUsageDescription作为字符串

在.h中

#import <CoreLocation/CoreLocation.h>

@interface ExamListVC : UIViewController<CLLocationManagerDelegate>
{
    CLLocationManager * locationManager;
}
@end

在 .m 中使用此代码

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    locationManager . delegate = self;

    [self initLocationManager];
}

    -(void)initLocationManager
    {
        locationManager=[[CLLocationManager alloc] init];
        locationManager.delegate=self;
        if (([locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]))
        {
            [locationManager requestWhenInUseAuthorization];
        }
        locationManager.desiredAccuracy = kCLLocationAccuracyBest;
        locationManager.distanceFilter = kCLDistanceFilterNone;
        [locationManager startUpdatingLocation];

    }


    -(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
    {
        CLLocation* location = [locations lastObject];
        NSDate* eventDate = location.timestamp;
        NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
        if (abs(howRecent) < 15.0)

        {
            NSLog(@"Current Coordinates are  %f,%f",location.coordinate.latitude,location.coordinate.longitude);
            [locationManager stopUpdatingLocation];
            }
        }

它会给出类似的输出

[2390:96060] 当前坐标为 37.332331,-122.031219