我觉得我已经在这个问题上阅读了很多帖子，许多答案各不相同，这使得事情变得非常困难。
简而言之，我想在后台更新用户位置，并定期将结果上传到API（理想情况下每90秒到5分钟）。经过一些挖掘后，我定期更新位置但是当我来调用NSOject类时会出现问题，而NSOject类又在 didUpdateToLocation 中运行 NSURLSessionDataTask （仅在NSDate已过期，因此不是每次调用该方法时都会将整个过程计时。
从测试中我发现通常设备运行此方法两次然后失败。我猜是因为操作系统正在告诉应用程序，因为呼叫太重了。
以下是我的Location方法和AppDelegate方法的样子......
AppDelege
-(void)applicationWillEnterForeground:(UIApplication *)application {
[self applicationUpdateLocationStatus:true];
}
-
-(void)applicationDidEnterBackground:(UIApplication *)application {
backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
[[UIApplication sharedApplication] endBackgroundTask:backgroundTask];
backgroundTask = UIBackgroundTaskInvalid;
}];
[self applicationUpdateLocationStatus:false];
}
-
-(void)applicationUpdateLocationStatus:(BOOL)foreground {
backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
[[UIApplication sharedApplication] endBackgroundTask:backgroundTask];
backgroundTask = UIBackgroundTaskInvalid;
}];
if ([self.location locationAllowed] && [self.user settingsVisible] && [[self.user userAccess] length] > 0) {
[self.location locationApplicationStatus:foreground];
}
}
位置对象
注意：从其他帖子开始和停止locationManager显然是关键
-(void)locationApplicationStatus:(BOOL)forground {
[self.locationManager stopUpdatingLocation];
[self.locationManager setDesiredAccuracy:kCLLocationAccuracyThreeKilometers];
[self.locationManager setDistanceFilter:5];
[self.locationManager setPausesLocationUpdatesAutomatically:false];
[self.locationManager setActivityType:CLActivityTypeOther];
[self.locationManager startUpdatingLocation];
}
在这里，我尝试使用startMonitoringSignificantLocationChanges，但它没有经常更新，同样的问题仍然存在。
-(void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error{
[self.locationManager stopUpdatingLocation];
}
-
-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
self.nearby = [[NearbyObject alloc] init];
self.currentLatitude = newLocation.coordinate.latitude;
self.currentLongitude = newLocation.coordinate.longitude;
self.currentAccuracy = newLocation.horizontalAccuracy;
[self.nearby queryNearby:[[CLLocation alloc] initWithLatitude:self.currentLatitude longitude:self.currentLongitude] completion:^(NSError *error, NSArray *content) {
//SAVE RETURN DATA HERE & EXPIRY
}];
}
附近对象
-(void)queryNearby:(CLLocation *)location completion:(void (^)(NSError *error, NSArray *content))completion {
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
sessionConfigure = [NSURLSessionConfiguration defaultSessionConfiguration];
session = [NSURLSession sessionWithConfiguration:sessionConfigure delegate:nil delegateQueue:[NSOperationQueue mainQueue]];
sessionURL = [NSURL URLWithString:[NSString stringWithFormat:@"%@user/usernearby.php" ,APP_BASE_URL]];
sessionTask = [session dataTaskWithURL:sessionURL completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
//COMPLETION HANDLER OUTPUT
}];
[sessionTask resume];
}];
}
注意：我已在应用启动时调用[self.locationManager requestAlwaysAuthorization];，并且用户已授予权限。