iPhone MKMapView - MKPolygon Issues

Question

I am trying to plot a MKPolygon on a MKMapView in iOS 4.0. I have an NSArray which contains custom objects that include properties for latitude/longitude. I have a code samp

Answer 1

The polygonWithCoordinates method wants a C array of CLLocationCoordinate2D structs. You can use malloc to allocate memory for the array (and free to release the memory). Loop through your NSArray and set it each element in the struct array.

For example:

coordsLen = [coordinateData count];
CLLocationCoordinate2D *coords = malloc(sizeof(CLLocationCoordinate2D) * coordsLen);
for (int i=0; i < coordsLen; i++)
{
    YourCustomObj *coordObj = (YourCustomObj *)[coordinateData objectAtIndex:i];
    coords[i] = CLLocationCoordinate2DMake(coordObj.latitude, coordObj.longitude);
}
MKPolygon *polygon = [MKPolygon polygonWithCoordinates:coords count:coordsLen];
free(coords);
[mapView addOverlay:polygon];

The viewForOverlay method should look like this:

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id )overlay
{
    MKPolygonView *polygonView = [[[MKPolygonView alloc] initWithPolygon:overlay] autorelease]; 
    polygonView.lineWidth = 1.0;
    polygonView.strokeColor = [UIColor redColor];
    polygonView.fillColor = [UIColor greenColor];
    return polygonView;
}