问题刷新iPhone的地图查看

Question

嘿家伙，我无法在我的地图视图中通过setNeedsDisplayInMapRect:函数刷新覆盖。下面是相关代码：

ParkingMapViewController.m：

for (ParkingRegionOverlay *overlay in mapView.overlays) { 
    [overlay setNeedsDisplayInMapRect:self.mapView.visibleMapRect]; 
} 

//... 
- (MKOverlayView *)mapView:(MKMapView *)mapView 
      viewForOverlay:(id <MKOverlay>)overlay 
{ 
    NSLog(@"ParkingMapViewController.m mapView:viewForOverlay"); 
    //... 
} 
//... 

ParkingRegionOverlay.h：

@interface ParkingRegionOverlay : MKOverlayView <MKOverlay> { 
    MKPolygon *polygon; 
    MKMapRect boundingRect; 
    CLLocationCoordinate2D centerCoord; 
    //... 
} 
//... 

而且我没有得到 “ParkingMapViewController.m的MapView：viewForOverlay” 输出到控制台我我期待。我已经走过调试器并确保for循环正在到达并执行，但由于某种原因，mapView:viewForOverlay:未被调用。任何人都知道我在做什么错了？提前致谢！

编辑1：

我相信我已经设置委托，协调，妥善边界矩形，但请看看...

ParkingMapViewController.h

@interface ParkingMapViewController : UIViewController <MKMapViewDelegate> { 
    MKMapView *mapView; 
//... 

ParkingMapViewController.m：

//... 
- (void)viewDidLoad { 
    [super viewDidLoad]; 
    mapView.delegate = self; 
//... 

ParkingRegionOverlay.m：

//... 
//initializes polygon and calculates bounding rect as well as its center coordinate 
-(id)initWithPoints:(NSArray *)pointsArray andTitle:(NSString *)overlayTitle{ 
    MKMapPoint points[[pointsArray count]]; 
    double maxX = MIN_COORD_VAL; 
    double minX = MAX_COORD_VAL; 
    double maxY = MIN_COORD_VAL; 
    double minY = MAX_COORD_VAL; 
    double tempX = 0; 
    double tempY = 0; 

    if (self = [super init]) { 
     int i = 0; 
     //determine min/max extrema to help calculate the bounding rect 
     for (id coordDict in pointsArray){ 
      tempX = [[coordDict objectForKey:@"latitude"] doubleValue]; 
      tempY = [[coordDict objectForKey:@"longitude"] doubleValue]; 
      maxX = fmax(tempX, maxX); 
      minX = fmin(tempX, minX); 
      maxY = fmax(tempY, maxY); 
      minY = fmin(tempY, minY); 

      CLLocationCoordinate2D coord = {tempX,tempY}; 
      points[i] = MKMapPointForCoordinate(coord); 
      i++; 
     }//for 

     CLLocationCoordinate2D northWestCorner = CLLocationCoordinate2DMake(maxX, minY); 
     CLLocationCoordinate2D southEastCorner = CLLocationCoordinate2DMake(minX, maxY); 
     MKMapPoint northWestPoint = MKMapPointForCoordinate(northWestCorner); 
     MKMapPoint southEastPoint = MKMapPointForCoordinate(southEastCorner); 
     boundingRect = MKMapRectMake(northWestPoint.x, northWestPoint.y, 
            (southEastPoint.x-northWestPoint.x), 
            (southEastPoint.y-northWestPoint.y)); 

     centerCoord = CLLocationCoordinate2DMake((maxX-minX)/2,(maxY-minY)/2); 
     polygon = [MKPolygon polygonWithPoints:points count:[pointsArray count]]; 
     polygon.title = overlayTitle; 

     [self initAcceptedPermitsBasedOnTitle:overlayTitle]; 
    }//if 

    return self; 
} 
//... 

谢谢。

编辑2：

的另一种方法我曾尝试，没有效果：

ParkingMapViewController.m

NSArray *overlayArray = [[NSArray alloc] initWithArray:[mapView overlays]]; 
    [self.mapView removeOverlays:mapView.overlays]; 
    [self.mapView addOverlays:overlayArray]; 

卸下和重新添加所有叠加层不工作太对我来说很好。它只是在第三行执行时崩溃。有任何想法吗？

编辑3：

所以我改变了以前发布的代码如下：

NSArray *overlayArray = [mapView overlays]; 
[self.mapView removeOverlays:overlayArray]; 
[self.mapView addOverlays:overlayArray]; 

，我现在看到这个控制台：

2011-05-05 14:24:54.145 Parking[68501:207] -[NSCFNumber boundingMapRect]: unrecognized selector sent to instance 0xa9afae0 
2011-05-05 14:24:54.147 Parking[68501:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSCFNumber boundingMapRect]: unrecognized selector sent to instance 0xa9afae0' 

Answer 1

所以我想通了。不一定是最有效的方法，但它适用于我。这是我做过什么：

[self.mapView removeOverlays:[mapView overlays]]; 
[self loadOverlaysAndAnnotations]; 

这里是loadOverlaysAndAnnotations：

- (void)loadOverlaysAndAnnotations { 

    NSError *error; 
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; 
    CoreDataSingleton *coreDataSingleton = [CoreDataSingleton sharedManager]; 
    NSEntityDescription *entity = [NSEntityDescription 
            entityForName:@"ParkingLot" inManagedObjectContext:[coreDataSingleton managedObjectContext]]; 
    [fetchRequest setEntity:entity]; 
    NSArray *fetchedObjects = [[coreDataSingleton managedObjectContext] executeFetchRequest:fetchRequest error:&error]; 
    for (NSManagedObject *overlayEntity in fetchedObjects) { 
     NSArray *pointsArray = [NSArray arrayWithArray:[overlayEntity valueForKey:@"overlayCoordPoints"]]; 
     ParkingRegionOverlay *regionPolygon = [[ParkingRegionOverlay alloc] initWithPoints:pointsArray andTitle:[overlayEntity valueForKey:@"lotName"]]; 
     [mapView addOverlay:regionPolygon]; 
     [regionPolygon release]; 


     NSSet *annotationsSet = [NSSet setWithSet:[overlayEntity valueForKey:@"parkingAnnotations"]]; 
     NSArray *allAnnotations = [NSArray arrayWithArray:[annotationsSet allObjects]]; 
     CLLocationCoordinate2D workingCoordinate; 
     for (ParkingAnnotations *annotation in allAnnotations) { 
      ParkingAnnotation *parkingAnnot = [[ParkingAnnotation alloc] init]; 
      workingCoordinate.latitude = [[annotation latitude] doubleValue]; 
      workingCoordinate.longitude = [[annotation longitude] doubleValue]; 
      [parkingAnnot setCoordinate:workingCoordinate]; 
      [parkingAnnot setTitle:[overlayEntity valueForKey:@"lotName"]]; 
      if ([[overlayEntity valueForKey:@"lotName"] isEqualToString:@"VP 1"]) { 
       [parkingAnnot setLot:lot1]; 
      } 

      [mapView addAnnotation:parkingAnnot]; 
      [parkingAnnot release]; 
     } 
    }   
    [fetchRequest release]; 
}//loadOverlaysAndAnnotations 

总之，我没有创建一个新的功能，但只是叫我用来加载覆盖到功能地图视图和工作正常！希望这有助于其他人陷入类似的情况。

编辑：

需要注意的是，我重装BOTH注释和覆盖，并且，如果没有先删除这两个注释和覆盖完成后，可能会导致您的应用程序崩溃，如果重载函数被调用过多次。这是我目前正在经历的。只是要注意的事情。为了解决这个问题，我将有单独的加载函数，一个用于覆盖，另一个用于注释，它将被适当地调用。

Answer 2

机会是你没有正确设置MKOverlay上的坐标或boundingMapRect属性。 MapView只会询问视图是否认为有可能是可见的，如果其可见矩形不与boundMapRect相交，则不会。

还要确保您的delegate为mapView设置正确。