ios - 根据当前位置在 UITableview 中排序距离

Question

我如何根据与当前位置的距离对数组进行排序并显示在表格 View 中。当我使用下面的代码进行排序时没有得到任何正确的结果，我得到的数组具有随机距离。有人可以指导我解决这个问题吗问题

-(void)sort_distance{
// Determine distance between current location and geofence location

[distance_array removeAllObjects];

NSMutableDictionary *dict=[[NSMutableDictionary alloc] init];
CLLocation *pinLocation;
CLLocation *userLocation;

for (int i=0; i<[self.geofences count]; i++) {

    //dict =[self.geofences objectAtIndex:i];

    CLLocationDegrees firstLat = [self.currentLatitude doubleValue];
    CLLocationDegrees firstLong = [self.currentLongitude doubleValue];

    CLLocationDegrees secondLat = [[[self.geofences objectAtIndex:i] objectForKey:@"lat"] doubleValue];
    CLLocationDegrees secondLong = [[[self.geofences objectAtIndex:i] objectForKey:@"lon"] doubleValue];


    pinLocation = [[CLLocation alloc]
                               initWithLatitude:secondLat
                               longitude:secondLong];

    userLocation = [[CLLocation alloc]
                                initWithLatitude:firstLat
                                longitude:firstLong];
    CLLocationDistance distance = [pinLocation distanceFromLocation:userLocation]/1000;

    //current distance is NSNumber


    CLLocationDistance kilometers = distance /1000;
    // or you can also use this..

    distanceString = [[NSString alloc] initWithFormat: @"%.1f Km", kilometers];

    NSLog(@"sa: %@", distanceString);


    [distance_array addObject:distanceString];

    [dict setObject:[NSNumber numberWithDouble:distance] forKey:@"newdistance"];


}
NSLog(@"distance array: %@", distance_array);







// Sorting the Geofence-Location depends on distance from current location


NSSortDescriptor * sort = [[NSSortDescriptor alloc] initWithKey:@"newdistance" ascending:YES];

NSArray *sortDescriptors = [NSArray arrayWithObject:sort];

sortedArray = [self.geofences sortedArrayUsingDescriptors:sortDescriptors];


}

我的输出是

距离数组:( "0.2 公里", "0.4 公里", "0.2 公里", "0.6 公里", "0.7 公里", "1.0 公里", “0.3 公里”)

提前致谢， 禅都。

Answer 1

-(void)sort_distance{
    // Determine distance between current location and geofence location

    [distance_array removeAllObjects];

    NSMutableDictionary *dict=[[NSMutableDictionary alloc] init];
    CLLocation *pinLocation;
    CLLocation *userLocation;

    for (int i=0; i<[self.geofences count]; i++) {

        //dict =[self.geofences objectAtIndex:i];

        CLLocationDegrees firstLat = [self.currentLatitude doubleValue];
        CLLocationDegrees firstLong = [self.currentLongitude doubleValue];

        CLLocationDegrees secondLat = [[[self.geofences objectAtIndex:i] objectForKey:@"lat"] doubleValue];
        CLLocationDegrees secondLong = [[[self.geofences objectAtIndex:i] objectForKey:@"lon"] doubleValue];


        pinLocation = [[CLLocation alloc]
                       initWithLatitude:secondLat
                       longitude:secondLong];

        userLocation = [[CLLocation alloc]
                        initWithLatitude:firstLat
                        longitude:firstLong];
        CLLocationDistance distance = [pinLocation distanceFromLocation:userLocation]/1000;

        //current distance is NSNumber


        CLLocationDistance kilometers = distance /1000;
        // or you can also use this..

        distanceString = [[NSString alloc] initWithFormat: @"%.1f km", kilometers];

        NSLog(@"sa: %@", distanceString);


        [distance_array addObject:distanceString];

        [dict setObject:[NSNumber numberWithDouble:distance] forKey:@"newdistance"];


    }
    NSLog(@"distance array: %@", distance_array);







    // Sorting the Geofence-Location depends on distance from current location


    sortedArray = [distance_array sortedArrayUsingSelector:@selector(compare:)];
    NSLog(@"%@",sortedArray);

}