我在一个应用程序中进行后台位置跟踪,但它太频繁了。我不确定设置更新位置的最小时间间隔的最佳技术是什么。我只想每隔2分钟左右保存一次位置数据。有些人说要使用NSTimer,但我不确定如何或在哪里将其纳入我当前的代码中。以下是我在AppDelegate中的所有位置跟踪代码,有人知道在我当前代码的情况下降低位置更新频率的最佳技术吗?
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
{
isBackgroundMode = NO;
_deferringUpdates = NO;
self.locationManager = [CLLocationManager new];
[self.locationManager setDelegate:self];
if ([self.locationManager respondsToSelector:@selector(requestAlwaysAuthorization)]) {
[self.locationManager requestAlwaysAuthorization];
}
[self.locationManager startUpdatingLocation];
[self.locationManager startMonitoringSignificantLocationChanges];
[self initializeRegionMonitoring];
}
-(void) initializeRegionMonitoring {
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
// notify changes when the device has moved x meters
self.locationManager.distanceFilter = 10;
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
[self.locationManager startUpdatingLocation];
[self.locationManager startMonitoringSignificantLocationChanges];
}
// Delegate method from the CLLocationManagerDelegate protocol.
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
[self saveLocation];
//tell the centralManager that you want to deferred this updatedLocation
if (isBackgroundMode && !_deferringUpdates)
{
_deferringUpdates = YES;
[self.locationManager allowDeferredLocationUpdatesUntilTraveled:CLLocationDistanceMax timeout:60];
}
}
- (void) locationManager:(CLLocationManager *)manager didFinishDeferredUpdatesWithError:(NSError *)error {
_deferringUpdates = NO;
}
-(void) saveLocation {
// save information database/ communication with web service
}
- (void)applicationWillResignActive:(UIApplication *)application {
isBackgroundMode = YES;
[self.locationManager stopUpdatingLocation];
[self.locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
[self.locationManager setDistanceFilter:kCLDistanceFilterNone];
self.locationManager.pausesLocationUpdatesAutomatically = NO;
self.locationManager.activityType = CLActivityTypeAutomotiveNavigation;
[self.locationManager startUpdatingLocation];
}
-(BOOL)application:(UIApplication *)application willFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
[[UIApplication sharedApplication] setMinimumBackgroundFetchInterval:UIApplicationBackgroundFetchIntervalMinimum];
return true;
}
-(void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {
[self saveLocation];
completionHandler(UIBackgroundFetchResultNewData);
NSLog(@"Fetch completed");
}
此外,由于我所做的很多工作都是从各种教程中编译的,请随时指出我在性能或电池使用方面做得不正确的地方。谢谢
在其他(开源(项目中,我看到了以下节能策略:
- 将请求的精度(setDesiredAccurcy(降低得很大(不是"kCLLocationAccuracyBest",而是"kCLLocation AccuracyKilometer"(
- 通过在"distanceFilter"中设置一个大阈值来减少回调"didUpdateLocations:"计数
- 如果不需要写入(使用其他条件,如时间(,则从回调返回
无论如何,我认为这里不需要额外的计时器。你想做的是从粗略的精度开始(如果可以的话!(,并将距离过滤器设置为一个高值(例如超过10米(。
此外,您还可以执行以下操作:在"didUpdateLocations:"回调中,如果"lastSaveTime"在if(lastSaveTime + 5 < thisSaveTime) { ... }
之前超过5分钟,则仅调用"saveLocation",假设时间以秒为单位。
正如您在中声明的那样
-(void) initializeRegionMonitoring
距离滤波器的值为10
self.locationManager.distanceFilter = 10;
因此,当用户移动到10米后,您的didUpdateLocations
将被调用,
如果要最小化此委托方法的调用,则必须增加distanceFilter
的值。
- 当用户时启动服务当地方精确度小于locationManager的精确度
-
位置管理器应该自动暂停&尝试使用简历locations委派。
-
检查上次位置和新位置的时间。
-
这将减少一些电池电量。
self.locationManager.distanceFilter = 10;
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
[self.locationManager startUpdatingLocation];
试试这个。。。。!!