objective-c - 使用 IBOutletCollections

Question

我有 30 个 UILabel，希望用作 IBOutlet。但是，当我尝试访问它们的 UILabel 属性时，我收到错误消息，提示我找不到类型为“id”的对象的属性 x。我对 Objective C 很生疏，所以怀疑我做了一些根本性的错误。我已将所有标签分配给 xib 文件中的 IBCollection。

.h

@interface ViewController : UIViewController
{
    IBOutletCollection(UILabel) NSArray *statPanels;
}
@property(retain) IBOutletCollection(UILabel) NSArray *statPanels;
@end

.m

@interface ViewController ()
@end

@implementation ViewController
@synthesize statPanels;

- (void)viewDidLoad
{
    [super viewDidLoad];

    statPanels = [[NSArray alloc] initWithObjects:[UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], nil ];

    [statPanels objectAtIndex:3].hidden = YES;
}

Answer 1

如果您在界面构建器中连接了所有标签，那么您不必初始化 statPanels 数组。

删除这一行:

statPanels = [[NSArray alloc] initWithObjects:[UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], [UILabel alloc], nil ];

那条线正在创建一个新数组和一堆新标签，并丢失了你的 socket 。

此外，您需要像其他答案所说的那样转换:

((UILabel *) [statPanels objectAtIndex:3]).property = ....