ios - 使用 Parse nearGeoPoint 检索用户位置

Question

我有一个用户表，每个用户都有自己的位置(PFGeoPoint 对象)。现在我要做的是从最近到最远的位置对用户进行排序和检索。问题是有些用户没有任何位置信息(纬度、经度、地理点)。他们的 currentLocation 列是空的。这就是查询无法按我预期工作的方式。

我将代码放在下面以保存用户位置以进行解析

    [PFGeoPoint geoPointForCurrentLocationInBackground:^(PFGeoPoint *geoPoint, NSError *error) {

    NSLog(@"User is currently at %f, %f", geoPoint.latitude, geoPoint.longitude);
    self.userLocation = geoPoint;
    [[PFUser currentUser] setObject:geoPoint forKey:@"currentLocation"];
    [[PFUser currentUser] saveInBackground];

 }];

然后将下面的代码放在我的检索查询方法中

PFGeoPoint *userGeoPoint = self.userLocation; //pass user location to PFGeoPoint

[query whereKey:@"currentLocation" nearGeoPoint:userGeoPoint]; //retrieve users from nearest to rarest 

Answer 1

如果用户没有地理点信息或不允许应用程序使用位置，我将手动将用户地理点信息更新为纬度 0.0、经度 0.0。然后我可以从最近到最远检索用户是否没有 geoopint 信息。我在 viewDidLoad 中使用的代码如下。

    CLAuthorizationStatus status = [CLLocationManager authorizationStatus];

if(status == kCLAuthorizationStatusAuthorized ||
   status == kCLAuthorizationStatusAuthorizedAlways ||
   status == kCLAuthorizationStatusAuthorizedWhenInUse) {

[PFGeoPoint geoPointForCurrentLocationInBackground:^(PFGeoPoint *geoPoint, NSError *error) {

    NSLog(@"User is currently at %f, %f", geoPoint.latitude, geoPoint.longitude);
    self.userLocation = geoPoint;
    [[PFUser currentUser] setObject:geoPoint forKey:@"currentLocation"];
    [[PFUser currentUser] saveInBackground];

 }];
}

else if (status == kCLAuthorizationStatusNotDetermined ||
         status == kCLAuthorizationStatusRestricted ||
         status == kCLAuthorizationStatusDenied) {

    PFGeoPoint *geoPoint = [PFGeoPoint geoPointWithLatitude:0.0 longitude:0.0];

    [[PFUser currentUser] setObject:geoPoint forKey:@"currentLocation"];
    [[PFUser currentUser] saveInBackground];
}