我试图根据两个位置之间的距离(当前位置和第一个 for 循环中指定的坐标)对 NSMutableArray 进行排序。但是，排序不会返回任何特定顺序，而是返回一个完全随机的顺序(参见此处的图片:http://u.maxk.me/iz7Z)。
你能告诉我哪里错了吗？
排序:
[self.venues sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
return [[obj1 objectForKey:@"distance"] compare:[obj2 objectForKey:@"distance"]];
}];
-setVenues:
- (void) setVenues:(NSMutableArray *)_venues {
if (venues != _venues) {
[venues release];
...
NSMutableArray *updatedVenues = [NSMutableArray array];
for (NSDictionary *venue in _venues) {
...
if (address != nil && city != nil) {
CLLocationCoordinate2D coord = CLLocationCoordinate2DMake([[_location objectForKey:@"lat"] floatValue], [[_location objectForKey:@"lng"] floatValue]);
CLLocation *currentLoc = [[CLLocation alloc] initWithLatitude:self.currentLocation.latitude longitude:self.currentLocation.longitude];
CLLocation *venueLoc = [[CLLocation alloc] initWithLatitude:coord.latitude longitude:coord.longitude];
CLLocationDistance distance = [venueLoc distanceFromLocation:currentLoc];
float miles = distance / 1000;
miles *= 0.621371192; // metres to miles
NSMutableDictionary *newLocation = [NSMutableDictionary dictionaryWithDictionary:_location];
[newLocation removeObjectForKey:@"distance"];
[newLocation setObject:[NSNumber numberWithFloat:miles] forKey:@"distance"];
_location = [NSDictionary dictionaryWithDictionary:newLocation];
...
NSMutableDictionary *newVenue = [NSMutableDictionary dictionaryWithDictionary:venue];
[newVenue removeObjectForKey:@"location"];
[newVenue setObject:_location forKey:@"location"];
[updatedVenues addObject:newVenue];
}
}
venues = [updatedVenues retain];
}
}
最佳答案
看起来你需要按 venue.location.distance 排序:
[self.venues sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
NSNumber *distance1 = [[obj1 objectForKey:@"location"] objectForKey:@"distance"];
NSNumber *distance2 = [[obj2 objectForKey:@"location"] objectForKey:@"distance"];
return [distance1 compare:distance2];
}];
如果您使用的 Xcode 版本 >= 4.4(iOS 为 4.5)，您可以这样做:
[self.venues sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
return [obj1[@"location"][@"distance"] compare:obj2[@"location"][@"distance"]];
}];
关于objective-c - NSMutableArray 排序返回不正确的顺序，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12788705/