Question

我有这个代码在地图上显示4个点，带有自定义图像。我已经开始了解，也许我构建它的方式不是最优的，但它就是我所拥有的。

请帮助我了解当有人点击它时，如何使用自定义poi将我创建的标题显示在地图上。

我有两个可以使用视图的类。这些类是MapAnnotation和LocationsViewController。

以下是每个代码。

MapAnnotation.h

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

@interface MapAnnotation : NSObject <MKAnnotation, MKMapViewDelegate> 
{
    CLLocationCoordinate2D _coordinate;
    NSString * title;

}

@property (nonatomic, copy) NSString *title;
- (id)initWithCoordinate:(CLLocationCoordinate2D)coordinate;

@end

MapAnnotation.m

#import "MapAnnotation.h"
#import "LocationsViewController.h"

@implementation MapAnnotation

@synthesize coordinate = _coordinate;
@synthesize title;

- (id)initWithCoordinate:(CLLocationCoordinate2D)coordinate
{
    self = [super init];

    if (self != nil)
    {
        _coordinate = coordinate;
    }

    return self;
}

@end

LocationsViewController.h

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

@interface LocationsViewController : UIViewController <MKMapViewDelegate, MKAnnotation>
{
    IBOutlet MKMapView *worldView;
    IBOutlet UIActivityIndicatorView *activityIndicator;

}

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id < MKAnnotation >)annotation;
@end

LocationsViewController.m

#import "LocationsViewController.h"
#import "MapAnnotation.h"
@interface LocationsViewController ()
@end

@implementation LocationsViewController

@synthesize coordinate = _coordinate;
@synthesize title;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Initialization code
    }
    return self;
}

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
{

    static NSString *AnnotationViewID = @"annotationViewID";

    MKAnnotationView *annotationView = (MKAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:AnnotationViewID];

    if (annotationView == nil)
    {
        annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:AnnotationViewID];
    }

    annotationView.image = [UIImage imageNamed:@"app_icon_sm.png"];
    annotationView.annotation = annotation;

    return annotationView;
}



- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    worldView.showsUserLocation = NO;

    CLLocationCoordinate2D wisconsin = {.latitude =  45.620775, .longitude =  -89.47844};
    CLLocationCoordinate2D pennsyvainia = {.latitude =  39.912417, .longitude =  -77.663268};
    CLLocationCoordinate2D nevada = {.latitude =  36.054362, .longitude =  -115.020470};
    CLLocationCoordinate2D texas = {.latitude =  32.555038, .longitude =  -94.295592};
    MapAnnotation *pinWI = [[MapAnnotation alloc] initWithCoordinate: wisconsin] ;
    MapAnnotation *pinPA = [[MapAnnotation alloc] initWithCoordinate: pennsyvainia];
    MapAnnotation *pinNV = [[MapAnnotation alloc] initWithCoordinate: nevada];
    MapAnnotation *pinTX = [[MapAnnotation alloc] initWithCoordinate: texas];
    //UIImage *star = [UIImage imageNamed:@"locations_marker.png"];
                        //////////////////
    pinWI.title = @"Rhinelander, WI";///////
    pinPA.title = @"Chambersburg, PA";//////I dont understand why these do not output a
    pinNV.title = @"Henderson, NV";/////////title if the title property is a part of the
    pinTX.title = @"Marshall, TX";////////// MKAnnotation
                        //////////////////
    [worldView addAnnotation:pinTX];
    [worldView addAnnotation:pinNV];
    [worldView addAnnotation:pinWI];
    [worldView addAnnotation:pinPA];

}

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

我想我需要一个函数来创建标题？我真的希望我不必创建更多类来完成这项工作。

Answer 1

您的主要问题是：

当有人点击时，如何使我创建的标题显示在地图上的自定义poi。

在viewForAnnotation委托方法中，您需要将注释视图的canShowCallout属性设置为YES（默认值为NO）：

if (annotationView == nil)
{
    annotationView = [[MKAnnotationView alloc] initWithAnnotation...
    annotationView.canShowCallout = YES;  // <-- add this line
}

一些与问题无关的其他评论：

在MapAnnotation.h中，此类只会实现MKAnnotation，而不是MKMapViewDelegate，因此请将其从协议列表中删除，以避免潜在的编译器警告并使代码更清晰，更清晰：
```
@interface MapAnnotation : NSObject <MKAnnotation>
```
在MapAnnotation.m中，您不需要#import "LocationsViewController.h"。删除它。
在LocationsViewController.h中，此类不正在实现MKAnnotation，因此将其从协议列表中删除，以避免潜在的编译器警告并使代码更清晰，更清晰：
```
@interface LocationsViewController : UIViewController <MKMapViewDelegate>
```
同样在LocationsViewController.h中，没有必要声明您将要实现的委托方法。您可以删除viewForAnnotation 声明。
在LocationsViewController.m中，@synthesize和coordinate的{{1}}不属于此处。删除它们。

Answer 2

-(void)locatePlaceonMap:(NSDictionary*)dic
{
[map_bar setScrollEnabled:YES];
map_bar.delegate = self;
MKCoordinateRegion zoomIn = map_bar.region;

zoomIn.span.latitudeDelta  = 0.1f;
zoomIn.span.longitudeDelta  = 0.1f;

zoomIn.center.latitude = ApplicationDelegate.latitude;
zoomIn.center.longitude = ApplicationDelegate.longitude;

[map_bar setRegion:zoomIn animated:NO];

MKPointAnnotation *annotation = [[MKPointAnnotation alloc]init];
annotation.title = [dic valueForKey:@"vName"];
annotation.subtitle = [dic valueForKey:@"t_long_address"];

CLLocationCoordinate2D newlocation = [map_bar.userLocation coordinate];
newlocation.latitude=[[dic valueForKey:@"dLat"]doubleValue];
newlocation.longitude=[[dic valueForKey:@"dLong"]doubleValue];
annotation.coordinate = newlocation;
[map_bar addAnnotation:annotation];
}


#pragma mark MkMapViewDelegate Methods

-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:   (id<MKAnnotation>)annotation
{
MKPinAnnotationView *pinView = nil;
static NSString *defaultPinID = @"ReusedPin";
pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:defaultPinID];

if ( pinView == nil )
    pinView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:defaultPinID];

if (annotation == mapView.userLocation) {

    return nil;

}else{
    pinView.image = [UIImage imageNamed:@"pin_trophy.png"];
    pinView.pinColor = MKPinAnnotationColorRed;
}
pinView.canShowCallout = YES;
pinView.animatesDrop = NO;

return pinView;
}

添加标注注释

2 个答案: