如何将注释标题传递给另一个视图控制器

Question

I am new to iOS programming, and I am having trouble with passing data between view controllers.

I have a view controller that geocodes an annotation on a map view, and sets the address as the title of the annotation view. The annotation view has a callout button that pushes another view to the stack, which has a label, and I want the address that was geocoded to show up as the label. Here is some code:

This is where I drop the pin:

-(void)press:(UILongPressGestureRecognizer *)recognizer
{
    CGPoint touchPoint = [recognizer locationInView:worldView];
    CLLocationCoordinate2D touchMapCoordinate = [worldView convertPoint:touchPoint toCoordinateFromView:worldView];

    geocoder = [[CLGeocoder alloc]init];
    CLLocation *location = [[CLLocation alloc]initWithCoordinate:touchMapCoordinate
                                                    altitude:CLLocationDistanceMax
                                          horizontalAccuracy:kCLLocationAccuracyBest
                                            verticalAccuracy:kCLLocationAccuracyBest
                                                   timestamp:[NSDate date]];
    [geocoder reverseGeocodeLocation:location
                   completionHandler:^(NSArray *placemarks, NSError *error) {
                       NSLog(@"reverseGeocoder:completionHandler: called");
                       if (error) {
                          NSLog(@"Geocoder failed with error: %@", error);
                       }
                       if (placemarks && placemarks.count > 0)
                       {
                           CLPlacemark *place = [placemarks objectAtIndex:0];
                           _address = [NSString stringWithFormat:@"%@ %@, %@ %@", [place subThoroughfare], [place thoroughfare], [place locality], [place administrativeArea]];

                           if (UIGestureRecognizerStateBegan == [recognizer state]) {
                               _addressPin = [[MapPoint alloc]initWithCoordinate:touchMapCoordinate
                                                                        title:_address];
                           [worldView addAnnotation:_addressPin];
                       }
                   }
               }];
}

Here is the code for the view where I want the address to show up:

#import <UIKit/UIKit.h>
@class MapPoint;

@interface PinViewController : UIViewController <UINavigationControllerDelegate,     UIImagePickerControllerDelegate,UITextFieldDelegate>

{
    __weak IBOutlet UILabel *addressLabel;
}

@property (weak, nonatomic) IBOutlet UIImageView *imageView;
@property (strong, nonatomic) MapPoint *pin;

-(void)takePicture:(id)sender;
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;

@end

#import "PinViewController.h"
#import "MapPoint.h"

@interface PinViewController ()

@end

@implementation PinViewController

@synthesize imageView, pin;
-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    [addressLabel setText:[pin title]];

}

The class MapPoint has a title property and subtitle property. When the PinViewController is pushed to the top of the stack, I try to set the text of the label to the title of the pin, but the label does not show any text. Can someone help me out and tell me what I am missing? Your help is greatly appreciated.

Answer 1

You must share more code blocks for this question :) . instead of you have to get more idea about Communication in Object-Oriented Programs

You can read a good tutorial about Passing Data Between View Classes here

Read best way to pass an object between two views here

There is a good document that i found in Developer.apple regarding CommunicatingWithObjects

Also you can watch a good video here

Answer 2

Just create property for the label and pass the label text from callout tapped method

- (void)mapView:(MKMapView *)mapView annotationView:(MKPinAnnotationView *)view calloutAccessoryControlTapped:(UIControl *)control {

    Details *det=[[Details alloc]init];
    det.label.text=annotation.title;
    [self.navigationController pushViewController:det animated:YES];
    [det release];
}