无法在MapKit中调用viewForAnnotation函数 [英] Cannot call viewForAnnotation function in MapKit

问题描述

我已经在StackOverflow中检查了很多问题，但它们都没有为我工作。

I have already checked many questions in StackOverflow but none of them worked for me.

我正在开发一个iPad应用程序。我在Storyboard中创建了所有接口。

I am developing an iPad application. I created all interfaces in Storyboard.

对于我的项目，我创建了一个视图控制器和相应的.h .m文件并将它们链接起来。然后我在视图控制器中添加了MKMapView，然后使用Interface Builder在视图控制器文件中引用了mapView。我创建了一堆点并在地图上显示它们。

For my project I created one view controller and corresponding .h .m files and linked them. Then I added MKMapView inside of the view controller then I referenced mapView in view controller file by using Interface Builder. I created bunch of points and showed them on map.

在我决定改变引脚颜色之前，一切都很完美。我在Apple Developer网站上关注了MapCallout示例。然后我创建了自定义注释点类，如下所示

Everything was perfect until I decided to change pin colors. I followed MapCallout example from Apple Developer site. Then I Created custom annotation point class as you see below

CustomMKAnnotation.h文件

CustomMKAnnotation.h file

@interface CustomMKAnnotation : NSObject <MKAnnotation>
{}

CustomMKAnnotation.m文件

CustomMKAnnotation.m file

@implementation CustomMKAnnotation

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

- (CLLocationCoordinate2D)coordinate;{
    CLLocationCoordinate2D theCoordinate;
    theCoordinate.latitude = some latitude;
    theCoordinate.longitude = some longitude;
    return theCoordinate; 
}
@end

这里是我的viewcontroller类

Here my viewcontroller class

MapHolderViewController.h文件

MapHolderViewController.h file

@interface MapHolderViewController : UIViewController<MKMapViewDelegate>
{
    NSMutableArray *mapAnnotations;
}
@property (nonatomic,retain) IBOutlet MKMapView *myMap;
@property (nonatomic, retain)  NSMutableArray *mapAnnotations;

-(void) addLatLong;

@end

MapHolderViewController.m文件

MapHolderViewController.m file

@implementation MapHolderViewController

@synthesize myMap;
@synthesize mapAnnotations;

-(void) addLatLong{
    // I am adding annotations here
}
- (MKAnnotationView *)myMap:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
{
    // This function has never been called.
}
@end

我将MKMapView的委托出口引用到ViewController。我还设置了myMap.delegate = self;在MapHolderViewController.m文件中，但它也无法正常工作。

I referenced delegate outlet from MKMapView to ViewController. I also set myMap.delegate=self; in MapHolderViewController.m file but it didn't work either.

欢迎任何见解。

推荐答案

问题似乎是你的委托方法没有正确命名。

The problem seems to be that your delegate method is not named correctly.

你已经编写了这样的委托方法：

You have written the delegate method like this:

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

所以你的方法是 myMap：viewForAnnotation：。

正确的标题是：

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

方法名称​​必须 mapView：viewForAnnotation：。

您可以更改参数名称（参数类型后面的名称）但不是参数类型前面的部分，它们是方法名称的一部分。

You can change the parameter names (the names after the parameter types) but not the parts in front of the parameter types which are part of the method name.

例如，这样就可以了：

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

这篇关于无法在MapKit中调用viewForAnnotation函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！