使用CLLocation计算两个坐标之间的距离 [英] Calculating Distance between two coordinates using CLLocation

问题描述

我使用 CLLocationDistance 来获得两点之间的距离，但是在传递我当前位置时出现错误。

I'm using CLLocationDistance to get the distance between two points, but I'm getting an error when passing my current location in it.

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);

推荐答案

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The error you're getting is actually:

使用不兼容类型CLLocationDistance（也称为'double'）初始化'CLLocationDistance *'（aka'double *'）

Initializing 'CLLocationDistance *' (aka 'double *') with an expression of incompatible type 'CLLocationDistance' (aka 'double')

它的意思是你正在初始化 itemDist CLLocationDistance （通知无星号）

What it's saying is you're initializing itemDist (which you've declared as a CLLocationDistance *) to something that is returning a CLLocationDistance (notice no asterisk).

CLLocationDistance 不是对象。

它只是一个原始类型（特别是 double - 请参阅核心位置数据类型参考）。

因此， code>作为指针添加到 CLLocationDistance ，只需将其声明为 CLLocationDistance （no asterisk）：

So instead of declaring itemDist as a pointer to a CLLocationDistance, just declare it as a CLLocationDistance (no asterisk):

CLLocationDistance itemDist = [itemLoc distanceFromLocation:current];

您还需要更新 NSLog 以期望 double 而不是对象，否则会在运行时崩溃：

You'll also need to update the NSLog to expect a double instead of an object otherwise it will crash at run-time:

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

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