如何在ios中多次停止調用didUpdateLocations（）的方法

Question

這是我的代碼......

 -(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
 {

    location_updated = [locations lastObject];
    NSLog(@"updated coordinate are %@",location_updated);
    latitude1 = location_updated.coordinate.latitude;
    longitude1 = location_updated.coordinate.longitude;

    self.lblLat.text = [NSString stringWithFormat:@"%f",latitude1];
    self.lblLon.text = [NSString stringWithFormat:@"%f",longitude1];

    NSString *str = [NSString stringWithFormat:@"https://maps.googleapis.com/maps/api/geocode/json?latlng=%f,%f&sensor=false",latitude1,longitude1];
    url = [NSURL URLWithString:str];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    connection = [NSURLConnection connectionWithRequest:request delegate:self];
    if (connection)
    {
        webData1 = [[NSMutableData alloc]init];
    }
        GMSMarker *marker = [[GMSMarker alloc] init];
        marker.position = CLLocationCoordinate2DMake(latitude1,longitude1);
        marker.title = formattedAddress;
        marker.icon = [UIImage imageNamed:@"m2.png"];
        marker.map = mapView_;
        marker.draggable = YES;
 }

這個方法多次調用，我不想......

Answer 1

雖然分配好自己的LocationManager對象，你可以設置distanceFilter的財產LocationManager 。 距離過濾器屬性是CLLocationDistance值，可以將其設置為通知位置管理器有關以米為單位移動的距離。 您可以按如下方式設置距離過濾器：

LocationManager *locationManger = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.distanceFilter = 100.0; // Will notify the LocationManager every 100 meters
locationManager.desiredAccuracy = kCLLocationAccuracyBest;

Answer 2

在那里添加一些限制。 對於位置和准確度之間的時間跨度

-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
 CLLocation *newLocation = locations.lastObject;

 NSTimeInterval locationAge = -[newLocation.timestamp timeIntervalSinceNow];
 if (locationAge > 5.0) return;

 if (newLocation.horizontalAccuracy < 0) return;

// Needed to filter cached and too old locations
 //NSLog(@"Location updated to = %@", newLocation);
 CLLocation *loc1 = [[CLLocation alloc] initWithLatitude:_currentLocation.coordinate.latitude longitude:_currentLocation.coordinate.longitude];
 CLLocation *loc2 = [[CLLocation alloc] initWithLatitude:newLocation.coordinate.latitude longitude:newLocation.coordinate.longitude];
 double distance = [loc1 distanceFromLocation:loc2];


 if(distance > 20)
 {    
     _currentLocation = newLocation;

     //significant location update

 }

//location updated

}

Answer 3

最簡單的方法：

-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray<CLLocation *> *)locations
{
   [manager stopUpdatingLocation];
    manager.delegate = nil;

   //...... do something

}

如果沒有委托引用，管理器找不到您的didUpdateLocations方法:-D

但是在使用startUpdatingLocation之前不要忘記再次設置它

Answer 4

我有類似的情況。 你可以使用dispatch_once：

static dispatch_once_t predicate;

- (void)update
{
    if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusNotDetermined &&
        [_locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
        [_locationManager requestWhenInUseAuthorization];
    }

    _locationManager.delegate = self;
    _locationManager.distanceFilter = kCLDistanceFilterNone;
    _locationManager.desiredAccuracy = kCLLocationAccuracyBest;

    predicate = 0;
    [_locationManager startUpdatingLocation];
}

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
    [manager stopUpdatingLocation];
    manager = nil;

    dispatch_once(&predicate, ^{
        //your code here
    });
}

Answer 5

您可以使用靜態變量來存儲最新的位置時間戳，然后將其與最新的位置時間戳進行比較，如下所示：

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
    [manager stopUpdatingLocation];
    static NSDate *previousLocationTimestamp;

    CLLocation *location = [locations lastObject];
    if (previousLocationTimestamp && [location.timestamp timeIntervalSinceDate:previousLocationTimestamp] < 2.0) {
        NSLog(@"didUpdateLocations GIVE UP");
        return;
    }
    previousLocationTimestamp = location.timestamp;

    NSLog(@"didUpdateLocations GOOD");

    // Do your code here
}

Answer 6

如果要停止更新位置管理器，請編寫此方法

[locationManager stopUpdatingLocation];

Answer 7

對於時間限制，我不理解接受的答案中的代碼，發布不同的方法。 正如Rob指出的那樣“當你第一次啟動位置服務時，你可能會多次看到它被調用”。 下面的代碼作用於第一個位置，並在前120秒忽略更新的位置。 它是解決原始問題“如何停止多次調用didUpdateLocations的方法”的一種方法。

在.h文件中：

@property(strong,nonatomic) CLLocation* firstLocation;

在.m文件中：

// is this the first location?
    CLLocation* newLocation = locations.lastObject;
    if (self.firstLocation) {
        // app already has a location
        NSTimeInterval locationAge = [newLocation.timestamp timeIntervalSinceDate:self.firstLocation.timestamp];
        NSLog(@"locationAge: %f",locationAge);
        if (locationAge < 120.0) {  // 120 is in seconds or milliseconds?
            return;
        }
    } else {
        self.firstLocation = newLocation;
    }

    // do something with location

Answer 8

你可以設置一個標志（Bool）。 當您實例化您的locationsManager set flag = true時，當locationManager：didUpdateLocations在您想要僅運行一次的代碼塊內返回set flag = false時。 這樣它只會運行一次。

 if flag == true {
     flag = false
    ...some code probably network call you only want to run the once 
    }

位置管理器將被多次調用，但是您只想執行一次代碼，我認為這是您要實現的目標？

Answer 9

locationManager.startUpdatingLocation（）連續獲取位置並且didUpdateLocations方法調用多次，只需在調用locationManager.startUpdatingLocation（）之前設置locationManager.distanceFilter值的值。

因為我設置200米（你可以根據你的要求改變）工作正常

    locationManager = CLLocationManager()
    locationManager.delegate = self
    locationManager.desiredAccuracy = kCLLocationAccuracyBest
    locationManager.distanceFilter = 200
    locationManager.requestWhenInUseAuthorization()
    locationManager.startUpdatingLocation()

Answer 10

你可以寫：[經理stopUpdatingLocation]; 經理=零; 在didupdatelocation委托中