用于更新多个视图的位置的单例 [英] singleton for location updating multiple views

问题描述

我希望在任何视图中按下导航栏中的locateButton后更新所有视图中的用户位置。我开始创建一个单身人士。

I want to update user location in ALL views, after the locateButton in the navbar is pressed in ANY view. I've started by creating a singleton.

Location.h

Location.h

#import <Foundation/Foundation.h>
#import <CoreLocation/CoreLocation.h>
#import <MapKit/MapKit.h>

@interface Location : NSObject <CLLocationManagerDelegate>

@property (nonatomic, strong) CLLocationManager* locationManager;

+ (Location*)sharedSingleton;

@end

Location.m

Location.m

#import "Location.h"

@implementation Location {
    CLLocationManager *locationManager;
    CLGeocoder *geocoder;
    CLPlacemark *placemark;
}


@synthesize locationManager;

- (id)init {
    self = [super init];

    if(self) {
        self.locationManager = [CLLocationManager new];
        [self.locationManager setDelegate:self];
        [self.locationManager setDistanceFilter:kCLDistanceFilterNone];
        [self.locationManager setHeadingFilter:kCLHeadingFilterNone];
        [self.locationManager startUpdatingLocation];
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
        //do any more customization to your location manager
    }

    return self;
}

+ (Location*)sharedSingleton {
    static Location* sharedSingleton;
    if(!sharedSingleton) {
        @synchronized(sharedSingleton) {
            sharedSingleton = [Location new];
        }
    }

    return sharedSingleton;
}

#pragma mark - CLLocationManagerDelegate

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    NSLog(@"didFailWithError: %@", error);
    UIAlertView *errorAlert = [[UIAlertView alloc]
                               initWithTitle:@"Error" message:@"Failed to Get Your Location" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [errorAlert show];
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    NSLog(@"didUpdateToLocation: %@", newLocation);

    CLLocation *currentLocation = newLocation;

    if (currentLocation != nil) {
        latLabel.text = [NSString stringWithFormat:@"%.8f", currentLocation.coordinate.longitude];
        longLabel.text = [NSString stringWithFormat:@"%.8f", currentLocation.coordinate.latitude];
    }

    // Stop Location Manager
    [locationManager stopUpdatingLocation];

    // Reverse Geocoding
    NSLog(@"Resolving the Address");
    [geocoder reverseGeocodeLocation:currentLocation completionHandler:^(NSArray *placemarks, NSError *error) {
        NSLog(@"Found placemarks: %@, error: %@", placemarks, error);
        if (error == nil && [placemarks count] > 0) {
            placemark = [placemarks lastObject];
            addressLabel.text = [NSString stringWithFormat:@"%@, %@",
                                 placemark.locality,
                                 placemark.administrativeArea];
            addressLabel.numberOfLines = 0;



        } else {
            NSLog(@"%@", error.debugDescription);
        }
    } ];

}

@end

我想要在当前视图中按下顶部导航栏中的locationButton时，使用此选项更新用户lat和long。

I want to use this to update user lat and long on every view when the locationButton in the top navbar is pressed in the current view.

- (IBAction)locationPressed:(id)sender { 

    [[Location sharedSingleton].locationManager startUpdatingLocation];

}

NSNotifications会是最好的吗？如果是这样，我将如何在Location.m和视图控制器中实现它们？谢谢。

Would NSNotifications be best? If so how would I implement them in Location.m and the view controllers? Thanks.

推荐答案

我会做的是使用观察者模式。在你的单身人士中，保留所有观察者的 NSMutableArray 。

What I would do would be to use the observer pattern. In your singleton, keep an NSMutableArray of all the observers.

NSMutableArray *observers;

您需要一个所有观察者都遵守的协议：

You'll need a protocol that all the observers will conform to:

@protocol LocationObserver <NSObject>

- (void)locationDidChange:(CLLocation *)updatedLocation;

@end

然后当位置发生变化时才这样做

and then when the location changes just do this

for (id<LocationObserver> observer in observers) {
    [observer locationDidChange:newLocation];
}

你应该有一个addObserver和removeObserver方法，并且需要 id< LocationObserver> 并在数组中添加/删除它。

You should have an addObserver and removeObserver method as well that take an id<LocationObserver> and add/remove it from the array.

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