获取指向另一个对象的成员的指针或引用-Gettingapointerorreferencetoamemberofanotherobject

Hi have an newbie issue with objective-c, cocoa & iPhone. I've declared mapView in my application delegates applicationDidFinishLaunching:application: which is instance/pointer of MKMapView class. mapView is a member of my application delegate.

大家好，我是objective-c, cocoa & iPhone的新手。我在应用程序委托applicationdidfinishlaunch:application中声明了mapView:application:它是MKMapView类的实例/指针。mapView是我的应用程序委托的成员。

In my view controller in viewDidLoad: I get instance of my application delegate with the following:

在viewDidLoad的视图控制器中:我获得应用程序委托的实例，如下所示:

appDelegate = [[UIApplication sharedApplication] delegate];

My view controller also has got MKMapView *mapView as a member. In viewDidLoad: I try to set it this way:

我的视图控制器也有MKMapView *mapView作为成员。在viewDidLoad:我试图这样设置:

mapView = [appDelegate mapView]; 

but it seems that I'm not able to get pointer or "reference" to the actual mapView because when I try to [mapView setRegion:region animated:YES]; it does not work. How ever [[appDelegate mapView] setRegion:region animated:YES]; does work.

但似乎我无法获得指向实际mapView的指针或"reference"因为当我尝试[mapView setRegion:region animated:YES];它不工作。如何([appDelegate mapView] setRegion:区域动画:是的);做的工作。

So the question is how do I get a pointer to appDelegates mapView from my view controller?

问题是如何从我的视图控制器中获得指向appdelegate mapView的指针?

2 个解决方案

@property (retain) id appDelegate;

[self setAppDelegate:[[UIAppliation sharedApplication] delegate]];

@property (assign) id appDelegate;