ios - UIView addSubview subview 不显示

Question

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    HeadViewController *headViewController = [[HeadViewController alloc] initWithNibName:@"HeadViewController" bundle:nil];    
    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 120)];
    [view addSubview:headViewController.vew];
    [self.view addSubview:view];
}

HeadViewController.h:

@interface HeadViewController : UIViewController
{
    IBOutlet UIView *view;
}
@property (nonatomic, retain)IBOutlet UIView *view;
@end

然后我将 View 连接到文件的所有者。

而且我看不到 headViewController.view。

Answer 1

首先，您不需要在HeadViewController 类中定义view outlet。它自动继承自 UIViewController 父类(super class)。

那么，我建议您直接将 HeadViewController 的 View 添加到您当前的 View 中。例如。

- (void)viewDidLoad
{
     [super viewDidLoad];
     // Do any additional setup after loading the view from its nib.
     HeadViewController *headViewController = [[HeadViewController alloc] initWithNibName:@"HeadViewController" bundle:nil];    
     headViewController.view.frame = CGRectMake(0, 0, 320, 120);
     [self.view addSubview:headViewController.view];
}

但是，如果您使用的是 ARC(自动引用计数)，headViewController 实例可能会在 viewDidLoad 方法结束后被释放。将该实例分配给您当前显示的 Controller 中的局部变量很方便(我会说这是强制性的)。这样您以后就可以在需要时处理它的 View 组件，实例将被保留，其他一切都将完美运行。你应该有这样的东西:

- (void)viewDidLoad
{
     [super viewDidLoad];
     // Do any additional setup after loading the view from its nib.
     self.headViewController = [[HeadViewController alloc] initWithNibName:@"HeadViewController" bundle:nil];    
     headViewController.view.frame = CGRectMake(0, 0, 320, 120);
     [self.view addSubview:headViewController.view];
}

和

@interface MyController ()
    @property (nonatomic, strong) HeadViewController *headViewController;
@end

在.m类实现文件开头的隐藏接口(interface)定义中。