ios - 注释按钮不显示

Question

我是第一次使用 Mapkit，我遇到了注释按钮不显示的问题。

我正在使用 xCode 5 和 iOS7。我也在 xCode 4.6 iOS 6.1 中尝试过，但也没有用。

ViewController.h

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

@interface ViewController : UIViewController <UITextFieldDelegate> {
IBOutlet UITextField *name;
MKMapView *mapView;
CLLocationManager *locationManager;
NSString *dateString;
NSString *nameString;
//MKPinAnnotationView *pinView;
NSString *pinID;

}

@property(nonatomic, retain) IBOutlet MKMapView *mapView;
@property(nonatomic, retain) UITextField *name;

-(IBAction)addPin;
-(IBAction)addName;

@end

ViewController.m

#import "ViewController.h"
#import "PinDrop.h"
#import <MapKit/MapKit.h>
#import <MapKit/MKAnnotation.h>

@interface ViewController ()

@end

@implementation ViewController
@synthesize mapView;
@dynamic name;

- (void)viewDidLoad
{
name.delegate = self;
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.

mapView.showsUserLocation = YES;

[mapView setMapType:MKMapTypeStandard];
[mapView setZoomEnabled:YES];
[mapView setScrollEnabled:YES];
//Get Location
locationManager = [[CLLocationManager alloc] init];
locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
[locationManager startUpdatingLocation];
NSLog(@"%@", [self deviceLocation]);

//Make Pin
MKCoordinateRegion region = { { 0.0, 0.0 }, { 0.0, 0.0 } };
region.center.latitude = locationManager.location.coordinate.latitude;
region.center.longitude = locationManager.location.coordinate.longitude;
region.span.longitudeDelta = 0.005f;
region.span.longitudeDelta = 0.005f;
[mapView setRegion:region animated:YES];
}

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

-(IBAction)addPin {
[self getDateTime];
//Get Location
locationManager = [[CLLocationManager alloc] init];
locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
[locationManager startUpdatingLocation];
NSLog(@"%@", [self deviceLocation]);

//Make Pin
MKCoordinateRegion region = { { 0.0, 0.0 }, { 0.0, 0.0 } };
region.center.latitude = locationManager.location.coordinate.latitude;
region.center.longitude = locationManager.location.coordinate.longitude;
region.span.longitudeDelta = 0.005f;
region.span.longitudeDelta = 0.005f;
[mapView setRegion:region animated:YES];


//Pin Info
PinDrop *ann = [[PinDrop alloc] init];
nameString = name.text;
NSLog(@"Name: %@", nameString);
ann.title = [NSString stringWithFormat:@"Title: %@", nameString];
ann.subtitle = [NSString stringWithFormat:@"Date: %@", dateString];
ann.coordinate = region.center;
[mapView addAnnotation:ann];

//Clear name and stuff
name.text = @"";

}
- (NSString *)deviceLocation {
return [NSString stringWithFormat:@"latitude: %f longitude: %f", locationManager.location.coordinate.latitude, locationManager.location.coordinate.longitude];
}

-(MKAnnotationView *)mapView:(MKMapView *)mV viewForAnnotation:
(id <MKAnnotation>)annotation {
MKPinAnnotationView *pinView = nil;
if(annotation != mapView.userLocation)
{
    static NSString *defaultPinID = @"com.invasivecode.pin";
    pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:defaultPinID];
    if ( pinView == nil ) pinView = [[[MKPinAnnotationView alloc]
                                      initWithAnnotation:annotation reuseIdentifier:defaultPinID] autorelease];

    pinView.pinColor = MKPinAnnotationColorGreen;
    pinView.canShowCallout = YES;
    pinView.animatesDrop = YES;
}
else {
    [mapView.userLocation setTitle:@"I am here"];
    NSLog(@"Was Else");
}
return pinView;
}
- (void)dealloc
{
[mapView release];
[super dealloc];
}
@end

PinDrop.h

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

@interface PinDrop : NSObject <MKAnnotation> {

CLLocationCoordinate2D coordinate;
NSString *title;
NSString *subtitle;

}

@property(nonatomic, assign) CLLocationCoordinate2D coordinate;
@property(nonatomic, copy) NSString *title;
@property(nonatomic, copy) NSString *subtitle;

@end

PinDrop.m

#import "PinDrop.h"

@implementation PinDrop
@synthesize coordinate, title, subtitle;


@end

Answer 1

几个想法:

1. 启动位置服务时，您应该

   • 指定self的委托(delegate)；和

   • View Controller 应该实现 CLLocationManagerDelegate打电话，didUpdateLocations

   您不能只启动位置服务，然后期望立即获得位置信息。您确实需要等待定位服务调用其委托(delegate)。事实上，请注意，物理设备上的位置服务实际上每次都需要进行几次迭代，精度不断提高(即更小的 horizo​​ntalAccuracy 值)。

2. 在您的 addPin 中，您实例化了一个新的位置管理器对象。 (顺便说一句，你也没有发布之前的那个。)你应该只使用你在 viewDidLoad 中创建的实例，而不是实例化一个新实例。

3. 你的 viewForAnnotation 被调用了吗？我希望您在 Interface Builder 中将 View Controller 指定为 map 的委托(delegate)。

4. 看起来您有一些类属性没有在 dealloc 中释放(例如位置管理器)。我会通过静态分析器(“产品”菜单上的“分析”)运行此代码，并更正它警告您的所有内容。