iphone - 如何将注释标题传递给另一个 View Controller

Question

我是 iOS 编程的新手，我在 View Controller 之间传递数据时遇到了问题。

我有一个 View Controller ，它对 map View 上的注释进行地理编码，并将地址设置为注释 View 的标题。注释 View 有一个标注按钮，可将另一个 View 推送到堆栈，该堆栈有一个标签，我希望经过地理编码的地址显示为标签。这是一些代码:

这是我放下图钉的地方:

-(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];
                       }
                   }
               }];
}

这是我希望显示地址的 View 的代码:

#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]];

}

类 MapPoint 有一个标题属性和副标题属性。当 PinViewController 被推到堆栈顶部时，我尝试将标签的文本设置为图钉的标题，但标签不显示任何文本。有人可以帮助我并告诉我我缺少什么吗？非常感谢您的帮助。

Answer 1

你必须为这个问题分享更多的代码块:)。而不是你必须更多地了解面向对象程序中的通信

您可以阅读有关在 View 类之间传递数据的好教程 here

阅读在两个 View 之间传递对象的最佳方式 here

我在 Developer.apple 中找到了一份关于 CommunicatingWithObjects 的好文档

还可以看个好视频here