動態創建MKPolygon

Question

我正在使用MKPolygon在UIMapView上進行疊加。以下是我目前的代碼：

CLLocationCoordinate2D commuterLotCoords[5]={ 
    CLLocationCoordinate2DMake(39.048019,-76.850535), 
    CLLocationCoordinate2DMake(39.048027,-76.850234), 
    CLLocationCoordinate2DMake(39.047407,-76.850181), 
    CLLocationCoordinate2DMake(39.047407,-76.8505), 
    CLLocationCoordinate2DMake(39.048019,-76.850535) 
}; 

MKPolygon *commuterPoly1 = [MKPolygon polygonWithCoordinates:commuterLotCoords count:5]; 
[commuterPoly1 setTitle:@"first"]; 
[self.overlayMap addOverlay:commuterPoly1]; 

現在，我正在實施json web服務，這將導致我所有的經度和緯度。但我無法從這些點創建覆蓋。任何人都可以幫助我使用動態點來實現疊加。

下面是我的服務響應：

{ 
    response_code: 1, 
    response_message: "successful", 
    districts: [ 
       { 
       district_id: "1", 
       district_name: "Austin", 
       Points: [ 
         { 
         latitude: "39.048019", 
         longitude: "-76.850535" 
         }, 
         { 
         latitude: "39.048027", 
         longitude: "-76.850234" 
         } 
         ] 
      }, 
      { 
       district_id: "2", 
       district_name: "Tulsa", 
       Points: [ 
         { 
         latitude: "39.048019", 
         longitude: "-76.850535" 
         }, 
         { 
         latitude: "39.048027", 
         longitude: "-76.850234" 
         }, 
         { 
         latitude: "39.047407", 
         longitude: "-76.850181" 
         }, 
         { 
         latitude: "39.047407", 
         longitude: "-76.8505" 
         }, 
         { 
         latitude: "39.048019", 
         longitude: "-76.850535" 
         } 
         ] 
       } 
     ] 
} 

在此先感謝

Answer 1

嘗試......從JSON創建字典，並通過它在這個函數...這將返回MKPolygon

-(MKPolygon *)getPointsForDic:(NSMutableDictionary *)dic 
{ 
    NSMutableSet *set = [[NSMutableSet alloc] init]; 
    NSMutableArray *arr = [dic valueForKey:@"districts"]; 

    for (int i = 0; i < arr.count; i++) 
    { 
     NSMutableDictionary *dicPoints = [arr objectAtIndex:i]; 
     [set addObjectsFromArray:[dicPoints valueForKey:@"Points"]]; 
    } 

    int count = set.count; 

    CLLocationCoordinate2D *coords = calloc(count, sizeof(CLLocationCoordinate2D)); 

    int i = 0; 

    for (NSMutableDictionary *dicT in set) 
    { 
     CLLocationCoordinate2D coord = CLLocationCoordinate2DMake([[dicT valueForKey:@"latitude"] floatValue], [[dicT valueForKey:@"longitude"] floatValue]); 
     coords[coordIdx++] = coord; 
     i++; 
    } 

    MKPolygon *commuterPoly1 = [MKPolygon polygonWithCoordinates:coords count:count]; 
    [commuterPoly1 setTitle:@"first"]; 

    return commuterPoly1; 
}