iPhone：根据位置排序 [英] iPhone: Sorting based on location

问题描述

我一直在研究iPhone应用程序，其中我有一个NSMutableArray中的用户列表，如下所示。

I have been working on an iPhone app, where-in i have list of users in a NSMutableArray like below.

myMutableArray: (
    {
        FirstName = Getsy;
        LastName = marie;
        Latitude = "30.237314";
        Longitude = "-92.461008";
    },
    {
        FirstName = Angel;
        LastName = openza;
        Latitude = "30.260329";
        Longitude = "-92.450414";
    },
    {
        FirstName = Sara;
        LastName = Hetzel;
        Latitude = "30.2584499";
        Longitude = "-92.4135357";
    }
)

我需要通过计算纬度和经度，根据我所在位置附近的位置对用户进行排序。到目前为止我无法做到这一点。有人可以帮我提供一些样品吗？

I need to sort users based on the location who is nearby to my location by calculating latitude and longitude. I am not able to achieve this till now. Could someone help me on giving some samples?

更新：我按照Mr.sch的建议尝试如下。请检查我的更新代码。没问题吗？。

UPDATED: I am trying like below as per Mr.sch suggested. Please check my updated code. Is it fine?.

    NSArray *orderedUsers = [myMutableArray sortedArrayUsingComparator:^(id a,id b) {
    NSArray *userA = (NSArray *)a;
    NSArray *userB = (NSArray *)b;
    CGFloat aLatitude = [[userA valueForKey:@"Latitude"] floatValue];
    CGFloat aLongitude = [[userA valueForKey:@"Longitude"] floatValue];
    CLLocation *participantALocation = [[CLLocation alloc] initWithLatitude:aLatitude longitude:aLongitude];

    CGFloat bLatitude = [[userA valueForKey:@"Latitude"] floatValue];
    CGFloat bLongitude = [[userA valueForKey:@"Longitude"] floatValue];
    CLLocation *participantBLocation = [[CLLocation alloc] initWithLatitude:bLatitude longitude:bLongitude];

    CLLocation *myLocation = [[CLLocation alloc] initWithLatitude:locationCoordinates.latitude longitude:locationCoordinates.longitude];

    CLLocationDistance distanceA = [participantALocation distanceFromLocation:myLocation];
    CLLocationDistance distanceB = [participantBLocation distanceFromLocation:myLocation];
    if (distanceA < distanceB) {
        return NSOrderedAscending;
    } else if (distanceA > distanceB) {
        return NSOrderedDescending;
    } else {
        return NSOrderedSame;
    }
}];

谢谢！

推荐答案

NSArray *orderedUsers = [users sortedArrayUsingComparator:^(id a,id b) {
     User *userA = (User *)a;
     User *userB = (User *)b;
     CLLocationDistance distanceA = [userA.location getDistanceFromLocation:myLocation];
     CLLocationDistance distanceB = [userB.location getDistanceFromLocation:myLocation];
     if (distanceA < distanceB) {
         return NSOrderedAscending
     } else if (distanceA > distanceB) {
         return NSOrderedDescending;
     } else {
         return NSOrderedSame;
     }
}];

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