ios - 如何将 CLLCoordinate2D lat/long 转换为 NSNumber

Question

我正在尝试使用 Yelp API，并且我正在尝试将纬度/经度作为 API 搜索的参数。但是，它不采用 double 类型，它只接受 Objective-C 对象。不了解 Objective-C，您建议 lat 和 long 的参数类型是什么？我尝试了 NSNumber，但是当我尝试将 CLLocationCoordinate2D 类型的纬度/经度坐标转换为采用 double 的 NSNumber 时，其值为 nil

这是我正在使用的 Yelp API:

- (void)queryTopBusinessInfoForTerm:(NSString *)term location:(NSString *)location latitude:(NSNumber *)latitude longitude:(NSNumber *)longitude completionHandler:(void (^)(NSDictionary *topBusinessJSON, NSError *error))completionHandler {

  NSLog(@"Querying the Search API with term \'%@\' and location \'%@'", term, location);

  //Make a first request to get the search results with the passed term and location
  NSURLRequest *searchRequest = [self _searchRequestWithTerm:term location:location latitude:latitude longitude:longitude];
  NSURLSession *session = [NSURLSession sharedSession];
  [[session dataTaskWithRequest:searchRequest completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;

if (!error && httpResponse.statusCode == 200) {

  NSDictionary *searchResponseJSON = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
  NSArray *businessArray = searchResponseJSON[@"businesses"];

  if ([businessArray count] > 0) {

    NSDictionary *firstBusiness = [businessArray firstObject];
    NSString *firstBusinessID = firstBusiness[@"id"];
    NSLog(@"%lu businesses found, querying business info for the top result: %@", (unsigned long)[businessArray count], firstBusinessID);

    [self queryBusinessInfoForBusinessId:firstBusinessID completionHandler:completionHandler];
  } else {
    completionHandler(nil, error); // No business was found
  }
} else {
  completionHandler(nil, error); // An error happened or the HTTP response is not a 200 OK
}
  }] resume];
}

这是参数

- (NSURLRequest *)_searchRequestWithTerm:(NSString *)term location:(NSString *)location latitude:(NSNumber *) latitude longitude:(NSNumber *)longitude {
  NSDictionary *params = @{
                       @"term": term,
                       @"location": location,
                       @"cll": latitude,
                       @"cll": longitude,
                       @"limit": kSearchLimit
                       };

  return [NSURLRequest requestWithHost:kAPIHost path:kSearchPath params:params];
}

这是我当前从 YelpAPI 调用查询的 Swift 方法:

func yelpApi() {
    var latitude = NSNumber(double: businessStreetAddress.latitude)
    var longitude = NSNumber(double: businessStreetAddress.longitude)
    var searchTerm: NSString = "Asian Food";
    var defaultLocation: NSString = "New York"
    var APISample:YPAPISample = YPAPISample();

    var requestGroup:dispatch_group_t = dispatch_group_create();


    APISample.queryTopBusinessInfoForTerm(searchTerm as String, location: defaultLocation as String, latitude: latitude, longitude: longitude) { (topBusinessJSON: [NSObject: AnyObject]!, error: NSError!) -> Void in
        if((error) != nil) {
            println("Error happened during the request" + error.localizedDescription);
        } else if((topBusinessJSON) != nil) {
            println("Top business info",topBusinessJSON);
        } else {
            println("No business was found");
        }

        dispatch_group_leave(requestGroup);
    }

    dispatch_group_wait(requestGroup, DISPATCH_TIME_FOREVER);


}

Answer 1

要将 CLLocationCoordinate2D 转换为 NSNumber，您不能将它放在单个 NSNumber 中。您可以转换为两个 NSNumber 对象，如下所示:

 CLLocationCoordinate2D location; // This is the location you have.
 NSNumber *latitude = [NSNumber numberWithDouble:location.latitude];
 NSNumber *longitude = [NSNumber numberWithDouble:location.longitude];

使用 Modern ObjC，您可以转换为:

 CLLocationCoordinate2D location; // This is the location you have.
 NSNumber *latitude = @(location.latitude);
 NSNumber *longitude = @(location.longitude);

然后调用你的

NSURLRequest *searchRequest = [self _searchRequestWithTerm:term location:location latitude:latitude longitude:longitude];

不要与名为 location 的变量混淆，我刚刚给它命名。因为您的函数 searchRequestWithTerm:location:latitude:longitude: 有一个名为 location 的参数，它接受 NSString。

这可能对你有帮助。