Question

我想在视图之间共享数据......

我有tabbar应用程序的appdelegate：

myappdelegate.h

#import <UIKit/UIKit.h>

@interface myappdelegate : NSObject <UIApplicationDelegate, UITabBarControllerDelegate> {
    UIWindow *window;
    UITabBarController *tabBarController;
    NSString  *result;
}


@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet UITabBarController *tabBarController;

@property (copy , readwrite) NSString *result;


@end

如果我想使用此命令调用，则有提示：“可能无法响应”....

   myappdelegate *dataCenter = [(myappdelegate *)[UIApplication sharedApplication] delegate];  <<may not respond
   dataCenter.result = @"msg";

result_view *resultView = [[result_view alloc] initWithNibName:@"result_view" bundle:nil];
[self.navigationController pushViewController:resultView animated:YES];
[resultView release];

result_view.m

- (void)viewDidLoad
{
    myappdelegate *dataCenter = (myappdelegate*)[[UIApplication sharedApplication]delegate];

    [label setText:dataCenter.result];
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
}

程序崩溃......

Answer 1

您的代码说sharedApplication属于myappdelegate类，它确实不响应delegate。这样做：

(myappdelegate *)[[UIApplication sharedApplication] delegate];

删除警告。

由于Objective-C的运行时消息传递，您当前的（生成警告）代码不会使应用程序崩溃。崩溃发生在其他地方。

Answer 2

你的第一行应该是

myappdelegate *dataCenter = (myappdelegate *)[[UIApplication sharedApplication] delegate];

关于第二行，我不知道你期望发生什么。您的myappdelegate类上没有result_array属性，因此您当然无法设置该属性。

如果您尝试设置result属性，则应该编写

dataCenter.result = @"msg";

视图UIApplication之间的数据

2 个答案: