iOS上的MapView错误

Question

我在Xcode上使用MapView，一切都很好，但当我添加以下行时

mapView.delegate = self;

到ViewController.m，我得到错误

正在分配给'id<MKMapViewDelegate>"来自不兼容的类型"ViewController*常量__强

这是我的代码：

ViewController.m:

#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
@synthesize mapView;
- (void)viewDidLoad
{
    [super viewDidLoad];
    mapView.showsUserLocation = YES;
    mapView.delegate = self; //The line I added that creates the error
    // Do any additional setup after loading the view, typically from a nib.
}
@end

ViewController.h

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
@interface ViewController : UIViewController {
    MKMapView *mapview;
}
@property (weak, nonatomic) IBOutlet MKMapView *mapView;
@end

Answer 1

您需要声明您的类实现了MKMapViewDelegate方法。在ViewController.h头文件中，更改行

@interface ViewController : UIViewController {

至

@interface ViewController : UIViewController <MKMapViewDelegate> {

Answer 2

您需要声明您响应了MKMapViewDelegate调用。

要做到这一点，只需更新相应类（示例中为ViewController.h）的头文件，如下所示：

@interface ViewController : UIViewController <MKMapViewDelegate> {