selectAnnotation不顯示標註

Question

我想更改MKMapView上顯示的標註。當我致電

[self.mapView selectAnnotation:annotation animated:YES]; 

它將地圖拖到註釋中，但不顯示其標註。我如何獲得它以顯示標註？

Answer 1

設置註釋對象上的title以及可選的subtitle屬性。 MapKit將自動顯示標註。

@interface MyAnnotation : NSObject <MKAnnotation> { 
    NSString *title; 
    NSString *subtitle; 
} 

@property (nonatomic, copy) NSString *title; 
@property (nonatomic, copy) NSString *subtitle; 

@end 

及實施，

#import "MyAnnotation.h" 

@implementation MyAnnotation 

@synthesize title, subtitle; 

@end 

用法，

MyAnnotation *foo = [[MyAnnotation alloc] init]; 
foo.title = @"I am Foo"; 
foo.subtitle = "I am jus' a subtitle"; 

Answer 2

應實現MKAnnotation委託方法

-(MKAnnotationView *)mapView:(MKMapView *)_mapView viewForAnnotation:(id<MKAnnotation>)annotation 
{ 
    static NSString *AnnotationViewIdentifier = @"AnnotationViewIdentifier"; 

    MKPinAnnotationView *annotationView = (MKPinAnnotationView *)[_mapView dequeueReusableAnnotationViewWithIdentifier:AnnotationViewIdentifier]; 
    if (annotationView == nil) 
    { 
     annotationView = [[[MKPinAnnotationView alloc]initWithAnnotation:annotation reuseIdentifier:AnnotationViewIdentifier]autorelease]; 
    } 

    annotationView.canShowCallout = YES; 

    return annotationView; 
}