Objective-c搜索具有半径的位置 [英] Objective-c search locations with radius

问题描述

是否有一个用于objective-c的库，它将允许我指定一个半径和一个位置，以及一个位置列表，并告诉我哪些位置在该半径范围内？
谢谢。

Is there a library in for objective-c that will allow me to specify a radius and a location, and a list of locations and tell me which locations are within that radius? Thanks.

推荐答案

如果你有CLLocations，那么类似这样的东西可以工作：

If you have CLLocations then something like this would work:

// Given NSArray *locations as an array of CLLocation* that you wish to filter

// and given a radius...
CLLocationDistance radius = kSomeRadius;

// and given a target you want to test against...
CLLocation* target = [[CLLocation alloc] initWithLatitude:someLat longitude:someLon];


NSArray *locationsWithinRadius = [locations objectsAtIndexes:
                                 [locations indexesOfObjectsPassingTest:
                                  ^BOOL(id obj, NSUInteger idx, BOOL *stop) {

                                      return [(CLLocation*)obj distanceFromLocation:target] < radius;

                                  }]];

[target release];

当然还有其他方法。这只是一种方式。

There are other ways to do this of course. This is just one way.

希望有帮助。

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