iOS: 当数据来自网络服务作为响应时，我如何获得多个经度和纬度的位置名称？

Question

我的代码需要帮助。我正在获取经度和纬度作为网络服务的响应。我需要将它们转换为位置名称并将其显示在相应的 table 视图单元格标签中。
以下是我的视图的响应、代码和屏幕截图，我在其中显示了我转换后的城市、国家/地区名称，并在我做错的地方更正了我的代码。

#import <UIKit/UIKit.h>
#import "JobTableViewCell.h"
#import "SlideNavigationController.h"
#import <CoreLocation/CoreLocation.h>

@interface JobPostedViewController : UIViewController <SlideNavigationControllerDelegate, UITableViewDataSource, CLLocationManagerDelegate>

@property (strong, nonatomic) NSArray* job_id;
@property (strong, nonatomic) NSArray* assigned_user_id;
@property (strong, nonatomic) NSArray* job_title;
@property (strong, nonatomic) NSArray* job_description;
@property (strong, nonatomic) NSArray* job_priority;
@property (strong, nonatomic) NSString* job_longitude;
@property (strong, nonatomic) NSArray* date;
@property (strong, nonatomic) NSString* job_latitude;
@property (strong, nonatomic) NSArray* job_completed;
@property (strong, nonatomic) NSArray* job_start_date;
@property (strong, nonatomic) NSArray* bids;

@property (nonatomic, strong) CLGeocoder *myGeocoder;

- (IBAction)onClickJobButton:(id)sender;


@property (weak, nonatomic) IBOutlet UIButton *sideNavigation;
@property (weak, nonatomic) IBOutlet UITableView *jobPostedTableView;

@end
`

    - (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.jobPostedTableView.dataSource = self;

    //Slide Navigation
    [self.sideNavigation addTarget:[SlideNavigationController sharedInstance] action:@selector(toggleLeftMenu) forControlEvents:UIControlEventTouchUpInside];

    WebManager *manager = [WebManager sharedInstance];
    [manager getJobPostedWithCompletionBlock:^(id response){
        NSDictionary *dictionary = (NSDictionary *)response;

        // Read data from JSON
        NSDictionary *responseObject = [dictionary objectForKey:@"response"];
        NSLog(@"The Array%@",responseObject);

        self.bids = [responseObject objectForKey:@"bids"];
        self.job_description = [responseObject objectForKey:@"job_description"];
        self.job_id = [responseObject objectForKey:@"job_id"];
        self.job_completed = [responseObject objectForKey:@"job_completed"];
        self.job_latitude = [responseObject objectForKey:@"job_latitude"];
        self.job_longitude = [responseObject objectForKey:@"job_longitude"];
        self.job_priority = [responseObject objectForKey:@"job_priority"];
        self.job_start_date = [responseObject objectForKey:@"job_start_date"];
        self.job_title = [responseObject objectForKey:@"job_title"];

        [self.jobPostedTableView reloadData];
    }];

        CLGeocoder *ceo = [[CLGeocoder alloc]init];
        CLLocation *loc = [[CLLocation alloc]initWithLatitude:[self.job_latitude floatValue] longitude:[self.job_longitude floatValue]]; //insert your coordinates

        [ceo reverseGeocodeLocation:loc
                  completionHandler:^(NSArray *placemarks, NSError *error) {
                      CLPlacemark *placemark = [placemarks objectAtIndex:0];
                      NSLog(@"placemark %@",placemark);
                      //String to hold address
                      [[placemark.addressDictionary valueForKey:@"FormattedAddressLines"] componentsJoinedByString:@", "];
                      NSLog(@"addressDictionary %@", placemark.addressDictionary);
                      NSArray *ar = [placemark.addressDictionary objectForKey:@"locality"];
                      NSLog(@"placemark %@",ar); // Extract the city name
                      NSLog(@"placemark %@",placemark.country);  // Give Country Name

                  }

         ];
    }


#pragma mark - SlideNavigationController Methods

- (BOOL)slideNavigationControllerShouldDisplayLeftMenu
{

    return YES;
}

#pragma mark - TableView Data Source

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [self.job_title count];
}

- (NSInteger) numberOfSectionsInTableview:(UITableView *)tableView
{
    return 1;
}

- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"JobTableViewCell";
    JobTableViewCell *cell = (JobTableViewCell *)[self.jobPostedTableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if(cell == nil) {

        cell = [[JobTableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
    }
    // Comparing array string to display an urgent image
    if ([[self.job_priority objectAtIndex:indexPath.row]
         isEqualToString:@"urgent"]) {
        cell.urgentLabel.hidden = NO;
    } else {
            cell.urgentLabel.hidden = YES;
    }
    // Condition whether job completed is open or closed
    if ([[self.job_completed objectAtIndex:indexPath.row]
         isEqualToString:@"1"]) {
        cell.jobStatus.text = @"Open";
        [cell.jobStatus setTextColor:[UIColor colorWithRed:(84/255.f) green:(56/255.f) blue:(255/255.f) alpha:1.0f]];
        cell.flagImage.image = [UIImage imageNamed:@"jobPosted_opened.PNG"];
    } else {
        cell.jobStatus.text = @"Closed";
        [cell.jobStatus setTextColor:[UIColor colorWithRed:(179/255.f) green:(179/255.f) blue:(180/255.f) alpha:1.0f]];
        cell.flagImage.image = [UIImage imageNamed:@"jobPosted_closed.PNG"];
    }


    cell.jobTitle.text = [self.job_title objectAtIndex:indexPath.row];
    cell.jobContent.text = [self.job_description objectAtIndex:indexPath.row];
    cell.bidsLabel.text = [[self.bids objectAtIndex:indexPath.row ]stringValue];
    return cell;

}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

Answer 1

解决方法如下：

将 NSString 更改为 NSArray 其中 properties:

@property (strong, nonatomic) NSString* job_longitude;
@property (strong, nonatomic) NSString* job_latitude;

添加一个新的 property 来保存地理编码结果：

@property (strong, nonatomic) NSMutableDictionary* reversedGeocodes;

在viewDidLoad:方法中设置reversedGeocodes：

self.reversedGeocodes = [NSMutableDictionary dictionary];

添加此方法以获取反向地理代码（并保存以备将来使用）：

- (void)locationNameWithLat:(float)lat
                        lng:(float)lng
          completionHandler:(void (^)(NSString *locationName, NSError *error))completion
{
    if (!lat || !lng)
        completion(@"Unknown location", nil);

    if (!completion || !lat || !lng)
        return;

    NSString *latStr = @(lat).description;
    NSString *lngStr = @(lng).description;

    // For each pair of lat and lng creating a unique key and saving the result
    // so we don't have to process the same pair multiple times.
    // Example:
    // lat = 23.039567; lng = 72.566004;
    // key = @"23.03956772.566004"; value would be whatever CoreLocation returns
    NSString *key = [latStr stringByAppendingString:lngStr];

    if (key.length) {
        if ([self.reversedGeocodes[key] length]) {
            completion (self.reversedGeocodes[key], nil);
        } else {
            self.reversedGeocodes[key] = @"Loading...";
            CLGeocoder *geocoder = [[CLGeocoder alloc] init];
            CLLocation *location = [[CLLocation alloc] initWithLatitude:lat longitude:lng];

            [geocoder reverseGeocodeLocation:location
                           completionHandler:^(NSArray *placemarks, NSError *error) {
                               if (error) {
                                   completion(@"Unknown location", error);
                               } else {
                                   CLPlacemark *placemark = placemarks.firstObject;
                                   NSString *locationName = placemark.country; // Default = country

                                   if (placemark.locality.length) // add city if available
                                       locationName = [NSString stringWithFormat:@"%@, %@", placemark.locality, placemark.country];

                                   self.reversedGeocodes[key] = locationName.length ? locationName : @"Unknown location";

                                   completion(self.reversedGeocodes[key], nil);
                               }
                           }
             ];
        }
    } else {
        completion(@"Unknown location", nil);
    }
}

在 return 之前从 cellForRowAtIndexPat: 方法调用上述方法 cell:

float lat = self.job_latitude[indexPath.row];
float lng = self.job_longitude[indexPath.row];

[self locationNameWithLat:lat
                      lng:lng
        completionHandler:^(NSString *locationName, NSError *error) {
            cell.locationName.text = locationName;
        }];

return cell;

P.S。如果我错过任何内容或拼写错误，请告诉我，因为我在这里输入了一些代码...

iOS: 当数据来自网络服务作为响应时，我如何获得多个经度和纬度的位置名称？

iOS: How can i get location names of multiple longitudes and latitudes when data is coming from web service as a response?

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