iphone - UIViewController 中的继承

Question

我正在努力继承 UIViewControllers 但遇到了问题。下面是我使用的 ViewController 列表及其流程。

头文件

MainViewController : UIViewController {

}

---

CustomerTicketViewController : UIViewController {

}
@property (nonatomic, retain) NSArray *listTickets;

---

CustomerEditTicketViewController : CustomerTicketViewController {

}

---

实施文件

@implementation MainViewController

- (void)loadCustomer {
        CustomerTicketViewController *customerTicketViewController = [[CustomerTicketViewController alloc] initWithNibName:@"CustomerTicketViewController" bundle:nil];
        [customerTicketViewController setListTickets:myTickets];
        [self presentModalViewController:customerTicketViewController animated:YES];
        [customerTicketViewController release];
}

@end

---

@implementation CustomerTicketViewController

    - (void)editCustomer {
        CustomerEditTicketViewController *customerEditTicketViewController = [[CustomerEditTicketViewController alloc] initWithNibName:@"CustomerEditTicketViewController" bundle:nil];
        NSLog(@"ParentView.listTickets: %@", listTickets);
        [self presentModalViewController:customerEditTicketViewController animated:NO];
        [customerEditTicketViewController release];
    }

    @end

---

@implementation CustomerEditTicketViewController

- (void)viewDidLoad {
    NSLog(@"listTickets: %@", listTickets);
    NSLog(@"super.listTickets: %@", super.listTickets);
    NSLog(@"self->listTickets: %@", self->listTickets);
    NSLog(@"self.listTickets: %@", self.listTickets);
}

@end

---

子类中的日志打印 null 但根据我的理解，它们应该打印与 ParentView 中相同的值。如果我在某些地方错了，请指导我。

    ParentView.listTickets: (
    "<CustomerTicket: 0x4c75d90>",
    "<CustomerTicket: 0x4c76310>"
)

listTickets: (null)
super.listTickets: (null)
self->listTickets: (null)
self.listTickets: (null)

Answer 1

您的编辑视图控制器是一个单独的对象。它从超类继承的只是它有一个名为 listTickets 的数组属性，而不是属性的值。这是面向对象编程的一个（？）基本点。

您必须在创建视图控制器后设置值，就像创建第一个视图控制器时一样：

CustomerEditTicketViewController *customerEditTicketViewController = [[CustomerEditTicketViewController alloc] initWithNibName:@"CustomerEditTicketViewController" bundle:nil];

customerEditTicketViewController.listTickets = self.listTickets;

Answer 2

您的视图控制器的 editCustomer 方法永远不会对子控制器的属性进行分配。