ios-IOS-MapView的錯誤

IOS-MapView的錯誤

使用MapView中， ViewController.m添加這行代碼之後就會報錯：

mapView.delegate = self;

錯誤：

Assigning to 'id<MKMapViewDelegate>' from incompatible type 'ViewController *const 
__strong'

代碼：

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.
}

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

@end

ViewController.h

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

@interface ViewController : UIViewController {
    MKMapView *mapview;
}
@property (weak, nonatomic) IBOutlet MKMapView *mapView;

@end

AppDelegate.m

#import "AppDelegate.h"

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application
{
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

- (void)applicationWillTerminate:(UIApplication *)application
{
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

@end

AppDelegate.h

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@end

最佳回答：

需要聲明你的類 MKMapViewDelegate 方法。在ViewController.h 頭文件中，修改

@interface ViewController : UIViewController {

改為：

@interface ViewController : UIViewController <MKMapViewDelegate> {