无法更改图钉 iOS MapKit 的颜色

Posted 2023-02-23

【中文标题】无法更改图钉 iOS MapKit 的颜色

【英文标题】：Trouble changing color of the pin iOS MapKit

【发布时间】：2010-10-21 19:55:15

【问题描述】：

我在更改 MapKit 中注释的 pinColor 时遇到问题。当我不尝试实现 mapView:viewForAnnotation: 方法时，一切正常（添加了注释）但是当我尝试更改注释视图时，模拟器崩溃：

代码如下：

MapViewController.h

#import "MapViewController.h"
#import <MapKit/MapKit.h>
#import <CoreLocation/CoreLocation.h>
#import "Annotation.h"


@implementation MapViewController

@synthesize myMapView;

/*
 // The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
    if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) 
        // Custom initialization
    
    return self;

*/


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad 
    [super viewDidLoad];
    CLLocationCoordinate2D location;
    location.longitude = 2.21;
    location.latitude = 48.5;
    MKCoordinateSpan span;
    span.latitudeDelta = 1*(1 - 0);
    span.longitudeDelta = 1*(1 - 0);
    MKCoordinateRegion region;
    region.span = span;
    region.center = location;
    [myMapView setRegion:region animated:NO];
    [myMapView regionThatFits:region];
    Annotation *someAnnotation =[[Annotation alloc] init];
    [myMapView addAnnotation:someAnnotation];
     



/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation 
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);

*/


- (MKAnnotationView *) mapView:(MKMapView *) mapView viewForAnnotation:(id<MKAnnotation>) annotation 
    MKPinAnnotationView *customPinview = [[[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:nil] autorelease];
    customPinview.pinColor = MKPinAnnotationColorGreen;
    customPinview.animatesDrop = YES;
    customPinview.canShowCallout = YES;
    return customPinview;




- (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.


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



- (void)dealloc 
    [super dealloc];



@end

MapViewController.m

//
//  MapViewController.h
//  TestMap
//
//  Created by Johan Ismael on 10/21/10.
//  Copyright 2010 __MyCompanyName__. All rights reserved.
//

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


@interface MapViewController : UIViewController<MKMapViewDelegate> 

@private

    IBOutlet MKMapView *myMapView;



@property (nonatomic, retain) IBOutlet MKMapView *myMapView;
//- (MKAnnotationView *) mapView:(MKMapView *) mapView viewForAnnotation:(id<MKAnnotation>) annotation;

@end

提前致谢！！！

注意：MapViewController 在 IB 中被声明为 MapView 的委托

【参考方案1】：

在 viewForAnnotation 方法中，alloc 是在 MKAnnotationView 而不是 MKPinAnnotationView 上完成的。它一定会因“无法识别的选择器”而崩溃，因为 MKAnnotationView 没有 pinColor 属性。将分配更改为：

MKPinAnnotationView *customPinview = [[[MKPinAnnotationView alloc] 
    initWithAnnotation:annotation reuseIdentifier:nil] autorelease];

【讨论】：

谢谢！对不起这个非常愚蠢的问题......:(