【问题标题】：Calculating Distance between two coordinates using CLLocation使用 CLLocation 计算两个坐标之间的距离
【发布时间】：2014-05-12 18:26:49
【问题描述】：

我正在使用CLLocationDistance 获取两点之间的距离，但在传递我当前的位置时出现错误。

CLLocation *current = [[CLLocation alloc] initWithLatitude:startLocation.coordinate.latitude longitude:startLocation.coordinate.longitude];
CLLocation *itemLoc = [[CLLocation alloc] initWithLatitude:[[[getName objectAtIndex:indexPath.row] objectForKey:@"lat"] doubleValue] longitude:[[[getName objectAtIndex:indexPath.row] objectForKey:@"lon"] doubleValue]];

//Here the current location gives me an error "Initializing cllocation with an expression incompatible format"
CLLocationDistance *itemDist = [itemLoc distanceFromLocation:current];
NSLog(@"Distance: %@", itemDist);

【问题讨论】：

标签： ios cocoa-touch ios7 cllocation

【解决方案1】：

你得到的错误实际上是：

使用不兼容类型“CLLocationDistance”（又名“double”）的表达式初始化“CLLocationDistance *”（又名“double *”）

它的意思是您正在将 itemDist（您已声明为 CLLocationDistance *）初始化为返回 CLLocationDistance（注意没有星号）的东西。

CLLocationDistance 不是对象。
它只是一个原始类型（特别是double -- 参见Core Location Data Types Reference）。

因此，不要将itemDist 声明为指向CLLocationDistance 的指针，只需将其声明为CLLocationDistance（无星号）：

CLLocationDistance itemDist = [itemLoc distanceFromLocation:current];

您还需要更新 NSLog 以期望 double 而不是 object 否则它将在运行时崩溃：

NSLog(@"Distance: %f", itemDist);

【讨论】：

【解决方案2】：

是swift 2.0是这样的：

let userLocation:CLLocation = CLLocation(latitude: 11.11, longitude: 22.22)
let priceLocation:CLLocation = CLLocation(latitude: 33.33, longitude: 44.44)
let meters:CLLocationDistance = userLocation.distanceFromLocation(priceLocation)

【讨论】：

【解决方案3】：

以下代码将为您工作在视图中加载

//************************** GEtting USer's latitude/ Longitude ********************




  self.locationManager = [[CLLocationManager alloc] init];
        self.locationManager.delegate = self;
        [self.locationManager startUpdatingLocation];
//************************** GEtting USer's latitude/ Longitude ********************

编译指示标记 - CLLocationManagerDelegate

- (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) {        
        CLLocation *locA = [[CLLocation alloc] initWithLatitude:currentLocation.coordinate.longitude longitude:currentLocation.coordinate.latitude];
        CLLocation *locB = [[CLLocation alloc] initWithLatitude:11.111111111111111 longitude:11.1111111111111111]; 
        User_Vanue_Distance = [locA distanceFromLocation:locB];
        NSLog(@"THIS IS THE DISTANCE BT TWO POINTS +++++++++++++++++++++%f",User_Vanue_Distance);  
    }
}

您需要将以下键放在 info.plist 中，在 ios 8 中要访问位置，我们需要将以下键放在 info.plist 中 1.NSLocationWhenInUseUsageDescription : Location required 2.NSLocationAlwaysUsageDescription Needed : Location Needed

这对您有用，但您需要添加的一件事是添加对 ios8 的检查。否则这将在 ios 7 上崩溃

// Check for iOS 8. Without this guard the code will crash with "unknown selector" on iOS 7.


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

希望这对你有用。 :)

【讨论】：

【解决方案4】：

从两个不同的纬度和经度中找到以 KM 为单位的距离

let userLocation:CLLocation = CLLocation(latitude: 23.0320, longitude: 72.5250)
let priceLocation:CLLocation = CLLocation(latitude: 23.0283, longitude: 72.5067)
let distance = String(format: "%.2f km", userLocation.distanceFromLocation(priceLocation)/1000)
print("Distance is KM is:: \(distance)")

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