ios - UIViewController 通过 xib 加载另一个 View Controller ，试图访问默认 View 导致崩溃

Question

所以，我有这个问题，这应该是微不足道的。我有一个 View Controller ，它正在从 xib 加载另一个 View Controller 。尝试引用该辅助 View Controller 的 View 时崩溃:

'NSInternalInconsistencyException', reason: '-[UIViewController _loadViewFromNibNamed:bundle:] loaded the "Embedded" nib but the view outlet was not set.'
*** First throw call stack:
(
    0   CoreFoundation                      0x000000010689134b __exceptionPreprocess + 171

执行此操作的代码片段如下所示:

- (void)viewDidLoad {
     [super viewDidLoad];

     // loads controller just fine.

     EbeddedViewController *embedded = [[EbeddedViewController alloc] initWithNibName:@"Embedded" bundle:nil];

     // KABOOM on line below 
     UIView *embeddedViewIs = embedded.view;

}

EmbeddedViewController 扩展了 UIViewController，而且非常普通/普通..

#import "EbeddedViewController.h"

@interface EbeddedViewController ()

@property (nonatomic, strong) IBOutlet UILabel *embeddedLabel;

@end

@implementation EbeddedViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end

这是非常无聊和普通的:



这是默认 View - 我尝试为它添加一个 IBOutlet，但它仍然崩溃。



使用自定义类正确设置了 xib View Controller :



我不知道为什么会崩溃。如果您想尝试这个小应用程序，请在此处下载:

Link to a tiny two view controller app where this crash is demonstrated

Answer 1

如果您想使用 xib 制作 Controller 的 View ，则不应将 Controller 添加到 InterfaceBuilder，只需添加一个 View 即可。

选择文件的所有者并设置自定义类 (EmbeddedViewController)

通过控制从文件所有者拖动到 View ，将文件所有者的 View 导出连接到新创建的 View ，如图