Question

我是iOS及其开发人员的新手。我已经阅读了Xcode旧样式在视图控制器之间传递数据。我已经看到很多事情都在使用xib文件。请在下面找到我用来传递数据的代码在ViewControllers之间。但是在 customelink （请找到DetailViewController.m）那里我得到Null值。请帮我在那里得到String值。并且足够解释什么是我在这里犯过的错误。

EssentialInfoController.h

#import <UIKit/UIKit.h>
#import "DetailViewController.h"
@interface Essentialinfocontroller : UIViewController
@end

EssentialInfoController.m

#import "Essentialinfocontroller.h"

@interface Essentialinfocontroller ()
@end

@implementation Essentialinfocontroller


- (void)viewDidLoad
{
    [super viewDidLoad];
    DetailViewController * customelink= [DetailViewController alloc ];
    customelink.link=@"https://www.facebook.com";



}

@end

DetailViewController.h

#import <UIKit/UIKit.h>

@interface DetailViewController : UIViewController
@property(weak,nonatomic)NSString * link;

@end

DetailViewController.m

 #import "DetailViewController.h"

    @interface DetailViewController ()

    @property(nonatomic,weak)NSString *customelink;
    @end

    @implementation DetailViewController
    @synthesize link;

    @synthesize customelink;


    - (void)viewDidLoad
    {
        [super viewDidLoad];
        self.customelink=self.link;


        NSLog(@"link--> %@",customelink);// here 2014-07-06 21:21:51.469 WADTourisum[880:60b] link--> (null)

    }

    @end

Answer 1

DetailViewController * customelink= [DetailViewController alloc ];

应该是

DetailViewController * customelink= [[DetailViewController alloc ] init];

和

@property(weak,nonatomic)NSString * link;

应该是

@property(strong,nonatomic)NSString * link;

并记录

NSLog(@"link--> %@",self.link);

你不需要这个

@property(nonatomic,weak)NSString *customelink;

如果您使用storyboard和segue，那么您必须实施 -(void)prepareForSegue方法。

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Make sure your segue name in storyboard is the same as this line
    if ([[segue identifier] isEqualToString:@"YOUR_SEGUE_NAME_HERE"])
    {
        // Get reference to the destination view controller
        YourViewController *vc = [segue destinationViewController];

        // Pass any objects to the view controller here, like...
        [vc setMyObjectHere:object];
    }
}

假设您有button从essentialVC移至detailVC，在您IBAction中，请调用此方法：

[self performSegueWithIdentifier:@"YOUR_SEGUE_NAME_HERE" sender:self];

这只是一个简短的答案。我建议你首先阅读UINavigationController，与segue，恕我直言相比，它更容易使用。

在视图控制器Xcode 5之间传递数据

1 个答案: