ios / xcode / objective-c：导航到嵌入在导航控制器中的模态视图控制器

Question

I have a segue from a button in a detail view controller to a new modal view controller that displays a map.

To pass the location to display on the map, I use preparetosegue as follows:

if ([segue.identifier isEqualToString:@"showMap"]) {

        IDMapView *destViewController = segue.destinationViewController;   
            destViewController.contact=_contact;
             }

However, I after embedding the modal view controller in a navigation controller to implement a cancel button, the app is now crashing when I click on the button giving the error in the log:

[UINavigationController setContact:]: unrecognized selector sent to instance 0x7f8738ea5ce0
(lldb) 

The error seems to have something to do with the navigation controller not having the property contact (which is on the view controller.)

Can anyone suggest the right way to do this?

Answer 1

The destinationViewController is now a UINavigationController and not an IDMapView . You need to get the topViewController from the UINavigationController .

if ([segue.identifier isEqualToString:@"showMap"]) {
    UINavigationController *navigationController = segue.destinationViewController;
    IDMapView *destViewController = navigationController.topViewController;   
    destViewController.contact=_contact;
}