Question

我试图将地标位置从CLGeocoder传递到名为cityLabel的另一个类UILabel。 CLGeocoder的类名为WXManager，mainViewController名为WXController。我已经尝试了各种方法使它工作，但我根本无法将城市名称传递给cityLabel。

WXManager.h

@class WXManager;
@protocol WXManagerDelegate <NSObject>

- (void)WXManagerDidGeocodeCityName:(NSString *)cityName;

@end

@interface WXManager : NSObject <CLLocationManagerDelegate>
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations;
@end

WXManager.m

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
if (self.isFirstUpdate) {
    self.isFirstUpdate = NO;
    return;
}

CLLocation *location = [locations lastObject];

if (location.horizontalAccuracy > 0) {
    self.currentLocation = location;
    [self.locationManager stopUpdatingLocation];}


CLGeocoder *fgeo = [[CLGeocoder alloc] init];

// Reverse Geocode a CLLocation to a CLPlacemark
[fgeo reverseGeocodeLocation:location completionHandler:^(NSArray *placemarks, NSError *error){

               if(!error){

                   for(CLPlacemark *placemark in placemarks){
                       self.cityName = [placemark locality];
                       [self.customDelegate WXManagerDidGeocodeCityName:self.cityName];
                       NSLog(@"city is %@",cityName); }

               } else {
                   NSLog(@"There was a reverse geocoding error\n%@",
                         [error localizedDescription]);
               }
           }
 ];
 }

WXController.h

@interface WXController : UIViewController
<WXManagerDelegate> 

- (void)WXManagerDidGeocodeCityName:(NSString *)cityName;

@end

最后在WXController.m中问题似乎是，我的方法WXManagerDidGeocodeCityName不会被调用。我不知道哪里错了。有谁知道怎么让这个方法被调用？

WXManager *cityName = [[WXManager alloc] init];
cityName.customDelegate = self;

#pragma mark - Custom Delegate Method

- (void)WXManagerDidGeocodeCityName:(NSString *)cityName
{

[self.cityLabel setText:cityName];
NSLog(@"cityName is %@", cityName);
NSLog(@"DidGetCalled");
}

日志没有被调用，所以必须在某处丢失。

Answer 1

试试这个：

<强> WXManager.h

@class WXManager;
@protocol WXManagerDelegate <NSObject>

- (void)WXManagerDidGeocodeCityName:(NSString *)cityName;

@end

@interface WXManager : NSObject <CLLocationManagerDelegate> {
id <WXManagerDelegate> customDelegate;
}

@property (retain)id customDelegate;

@end

<强> WXController.h

@interface WXController : UIViewController <WXManagerDelegate> 

//- (void)WXManagerDidGeocodeCityName:(NSString *)cityName;

@end

Answer 2

在WXManager.m中，您需要初始化CLLocationManager：

self.locationManager = [[CLLocationManager alloc] init];

self.locationManager.delegate = self;
[self.locationManager startUpdatingLocation];

一切都会好起来的

Answer 3

我猜测cityName是weak，或者有一个自定义的setter / getter来清除/忽略正确的值。

编辑以澄清：

我在这里谈论你的cityName：

WXManager *cityName = [[WXManager alloc] init];
cityName.customDelegate = self;

我假设稍后会为其分配一些属性self.cityName。如果不这样做，那么在完成处理程序运行之前，self.customDelegate将变为nil。

Answer 4

该方法未被调用？或变量cityName等于nil？

如果是第一个 - 寻找你的代表可能是等于零。如果第二个 - CLGeocoder工作不正确。

一般是漫步调试器。看看变量。快速了解一切。

Answer 5

在WXManager.m中，您需要初始化CLLocationManager：

self.locationManager = [[CLLocationManager alloc] init]; self.locationManager.delegate = self; [self.locationManager startUpdatingLocation];

一切都会好起来的

使用委托协议传递CLGeocoder城市名称

5 个答案: