注释标注标题不变

Question

我已经搜索过，但没有找到任何解决我的问题的方法。我想更改已添加的引脚。这是我的代码。我在控制台中收到“Code Here”。

我在 .h

- (void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView         *)annotationView;

myViewController.m

- (void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)annotationView
{
    userPins *myAnnot = (userPins *)annotationView.annotation;
    [myAnnot setTitle:@"o21"];
    NSLog(@"Code here!");
}

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation {
    static NSString *identifier = @"userPins";   
    if ([annotation isKindOfClass:[userPins class]]) {

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

        annotationView.image = [UIImage imageNamed:@"mapMarker-blue.png"];
        annotationView.calloutOffset = CGPointMake(0,0);

        UIButton *detailButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
        annotationView.rightCalloutAccessoryView = detailButton;

        annotationView.enabled = YES;
        annotationView.canShowCallout = YES;

        return annotationView;

    }

    return nil;   

}

中有，在 userPins.mi 中有。但我也没有用 setTitle 这样做。

- (void)setTitle:(NSString *)title {
    if (_subtitle != subtitle) {
        [_subtitle release];
        _subtitle = [subtitle retain];
    }
}

- (NSString *)title{
    return @"okan";
}

编辑：@AnnaKarenina

我已经尝试了所有。但 setTitle 没有运行。我要疯了！这是我的全部代码。而且我没有收到错误。

userpins.m

#import "userPins.h"

@implementation userPins
@synthesize fbid = _fbid;
@synthesize coordinate = _coordinate;
@synthesize title = _title;
@synthesize subtitle = _subtitle;


- (id)initWithfbid:(NSInteger*)fbid 
        coordinate:(CLLocationCoordinate2D)coordinate {
    if ((self = [super init])) {
        _fbid = fbid;
        _coordinate = coordinate;
    }
    return self;
}


- (NSString *)subtitle{
    return @"Anything";
}
- (NSString *)title{
    return @"Something";
}

- (void)dealloc
{
    [_title release];
    [_subtitle release];
    [super dealloc];
}

@end

userPins.h

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

@interface userPins : NSObject <MKAnnotation> {
    NSInteger *_fbid;
    CLLocationCoordinate2D _coordinate;
    NSString *_title;
    NSString *_subtitle;
}

@property (nonatomic, readonly) NSInteger *fbid;
@property (nonatomic, readonly) CLLocationCoordinate2D coordinate;
@property (nonatomic, copy) NSString *title;
@property (nonatomic, copy) NSString *subtitle;
- (id)initWithfbid:(NSInteger*)fbid coordinate:(CLLocationCoordinate2D)coordinate;

@end

viewController.m

#import "lociseViewController.h"
#import "ASIHTTPRequest.h"
#import "SBJSON.h"
#import "userPins.h"

@implementation lociseViewController
@synthesize mapView = _mapView;


- (void)didReceiveMemoryWarning
{
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

#pragma mark - View lifecycle

// Add new method above refreshTapped
- (void)plotPositions:(NSString *)responseString {

    for (id<MKAnnotation> annotation in _mapView.annotations) {
        [_mapView removeAnnotation:annotation];
    }

    NSDictionary * root = [responseString JSONValue];
    NSArray *data = [root objectForKey:@"data"];
    for (NSArray * row in data) {
        NSInteger * fbid = (NSInteger *)[row objectAtIndex:0];
        NSNumber * latitude = [row objectAtIndex:1];
        NSNumber * longitude = [row objectAtIndex:2];

        CLLocationCoordinate2D coordinate;
        coordinate.latitude = latitude.doubleValue;
        coordinate.longitude = longitude.doubleValue;            
        userPins *annotation = [[[userPins alloc] initWithfbid:fbid coordinate:coordinate] autorelease];
        [_mapView addAnnotation:annotation];        
    }


}

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
    // 1
    MKCoordinateRegion mapRegion = [_mapView region];
    CLLocationCoordinate2D centerLocation = mapRegion.center;

    // 2
    NSString *jsonFile = [[NSBundle mainBundle] pathForResource:@"command" ofType:@"json"];

    NSString *formatString = [NSString stringWithContentsOfFile:jsonFile encoding:NSUTF8StringEncoding error:nil];
    NSString *json = [NSString stringWithFormat:formatString,                     centerLocation.latitude, centerLocation.longitude, 0.5*METERS_PER_MILE];


    NSURL *url = [NSURL URLWithString:@"http://localhost/users.json"];


    ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
    request.requestMethod = @"POST";  
    //request.defaultResponseEncoding = NSISOLatin1StringEncoding;
    //[request addRequestHeader:@"Content-Encoding" value:@"windows-1255"];
    [request addRequestHeader:@"Content-Type" value:@"application/json"];
    [request appendPostData:[json dataUsingEncoding:NSUTF8StringEncoding]];
    [request setDefaultResponseEncoding:NSUTF8StringEncoding];

    // 5
    [request setDelegate:self];
    [request setCompletionBlock:^{        
        NSString *responseString = [request responseString];
        NSLog(@"Response: %@", responseString);
        [self plotPositions:responseString];
    }];
    [request setFailedBlock:^{
        NSError *error = [request error];
        NSLog(@"Error: %@", error.localizedDescription);
    }];

    // 6
    [request startAsynchronous];
    //CLLocationManager *locationManager;
    //locationManager.delegate = self;

    [super viewDidLoad];

}


- (void)viewWillAppear:(BOOL)animated {  
    // 1
    CLLocationCoordinate2D zoomLocation;
    zoomLocation.latitude = 35.333070;
    zoomLocation.longitude = 33.302875;

    // 2
    MKCoordinateRegion viewRegion = MKCoordinateRegionMakeWithDistance(zoomLocation, 50*METERS_PER_MILE, 3*METERS_PER_MILE);
    // 3
    MKCoordinateRegion adjustedRegion = [_mapView regionThatFits:viewRegion];                
    // 4

    [_mapView setRegion:adjustedRegion animated:YES];        
}

- (void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)annotationView
{
    userPins *myAnnot = (userPins *)annotationView.annotation;
    [myAnnot setTitle:@"o21"];

    NSLog(@"Title: %@", annotationView.annotation.subtitle);

}


- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation {
    static NSString *identifier = @"userPins";   
    if ([annotation isKindOfClass:[userPins class]]) {


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


        annotationView.image = [UIImage imageNamed:@"mapMarker-blue.png"];
        annotationView.calloutOffset = CGPointMake(0,0);

        UIButton *detailButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
        annotationView.rightCalloutAccessoryView = detailButton;


        annotationView.enabled = YES;
        annotationView.canShowCallout = YES;

        return annotationView;

    }

    return nil;   

}



- (void)viewDidUnload
{
    [self setMapView:nil];
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

- (void)dealloc {

    [_mapView release];
    [super dealloc];
}
@end

viewController.h

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>

#define METERS_PER_MILE 1609.344

@interface lociseViewController : UIViewController <MKMapViewDelegate> {
    MKMapView *_mapView;
}

@property (nonatomic, retain) IBOutlet MKMapView *mapView;
- (void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)annotationView;


@end

Answer 1

userPins.m 中的 setTitle: 和 title 方法看起来不正确。

setTitle: 方法查看并设置副标题而不是标题。 title 方法返回一个常量字符串，因此即使 setTitle: 设置标题 ivar，注释也会返回相同的常量字符串。

您可以修复这些方法，或者仅将 title 和 subtitle 声明为 copy 属性，并在 userPins.m 中将它们声明为 @synthesize （并在 dealloc 中释放）。那么你就根本不需要这些方法（它们会自动实现）。

顺便说一句，当您添加注释时，请务必将标题设置为某些内容（即使是一个空格），否则标注将不会显示，并且 didSelectAnnotationView 将不会被调用。

另一个问题是 viewForAnnotation 中的内存泄漏。您应该在 alloc+init annotationView 位置添加一个 autorelease。

关于更新的代码：

在userPins.m中，它仍然返回subtitle和title的常量字符串，从而隐藏了更改的ivars。将其更改为：

- (id)initWithfbid:(NSInteger*)fbid 
        coordinate:(CLLocationCoordinate2D)coordinate {
    if ((self = [super init])) {
        _fbid = fbid;
        _coordinate = coordinate;

        //init the ivars here...
        _title = @"Something";
        _subtitle = @"Anything";
    }
    return self;
}

/* comment these methods out
- (NSString *)subtitle{
    return @"Anything";
}
- (NSString *)title{
    return @"Something";
}
*/

一个新的、不相关的问题是 fbid 可能应该是 NSNumber * 而不是 NSInteger *。 NSInteger 不是一个对象，而 NSNumber 是 JSON 解析器最有可能为您提供的内容。