我无法让 MKAnnotationViews 显示在 MapKit 的地图上。我正在使用 iOS 7,现在已经在论坛和网络上搜索了很多小时,尝试不同的示例和设置。
下面我有(我认为)使其工作的最基本的设置。该应用程序包含一个 ViewController,其工具栏顶部有一个按钮,其余部分是 MapView。该按钮触发方法zoomToUser:(UIBarButtonItem*)sender。右键单击并检查我的商店和代表似乎是正确的。我有一些 NSLog 语句被触发以输出一些调试信息。
首先是风险投资:
#import "ViewController.h"
#import "Data.h"
@interface ViewController () <MKMapViewDelegate>
@property (weak, nonatomic) IBOutlet MKMapView *mapView;
- (IBAction)zoomToUser:(UIBarButtonItem *)sender;
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self.mapView.showsUserLocation = YES;
Data *ann = [[Data alloc] init];
[self.mapView addAnnotation:ann];
}
-(void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[self zoomToUser:nil];
}
-(IBAction)zoomToUser:(UIBarButtonItem *)sender
{
MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(self.mapView.userLocation.coordinate, 2000, 2000);
NSLog(@"region: %f x %f",self.mapView.userLocation.coordinate.latitude,self.mapView.userLocation.coordinate.longitude);
[self.mapView setRegion:region animated:YES ];
NSArray *arr = self.mapView.annotations;
for(int i = 0, max = arr.count; i < max; i++)
{
id<MKAnnotation> annotation = arr[i];
NSLog(@"%d of %d: %@ (%@)",i+1,max,annotation.title, [annotation class]);
}
}
- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation
{
NSString *reuseId = @"Test";
if([annotation isKindOfClass:[MKUserLocation class]])
{
return nil;
}
else if( [annotation isKindOfClass:[Data class]])
{
MKAnnotationView *annov = [mapView dequeueReusableAnnotationViewWithIdentifier:reuseId];
if(!annov)
{
annov = [[MKAnnotationView alloc]initWithAnnotation:annotation
reuseIdentifier:reuseId];
}
else
{
annov.annotation = annotation;
}
annov.canShowCallout = YES;
NSLog(@"Title: %@",annotation.title);
return annov;
}
else
{
return nil;
}
}
@end
And the Data
class:
#import "Data.h"
@implementation Data
-(NSString *)title
{
return @"The title";
}
-(NSString *)subtitle
{
return @"A subtitle";
}
-(CLLocationCoordinate2D)coordinate
{
CLLocationCoordinate2D coordinate;
coordinate.latitude = 60.123456;
coordinate.longitude = 10.123456;
return coordinate;
}
@end
数据.h:
#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>
@interface Data : NSObject <MKAnnotation>
@end
和 ViewController.h:
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
@interface ViewController : UIViewController
@end
正如你所看到的viewForAnnotation
-method 在请求时在控制台中打印注释标题,并且每次地图平移该区域时,都会打印。
按下 BarButton 并触发zoomToUser:
- 方法记录到控制台,该地图确实有两个注释,MKUserLocation
以及我添加的那个。
为什么我的 MapView 告诉我它有注释,它请求视图,它获取视图,但它不显示它?