UIViewController -viewDidLoad未被调用 [英] UIViewController -viewDidLoad not being called

问题描述

作为Cocoa新手，我遇到了 Interface Builder ， UIViewController 和朋友的几个问题。 / p>

我有一个 UIViewController 子类与 UIView 一个xib，并且控制器的视图出口连接到视图。 xib的文件所有者设置为 myViewcontroller 子类。

在这一个实例中，加载控制器/视图主视图控制器）不能按预期工作：

  if（self.myViewController == nil）
 { 
 self.myViewController = [[MyViewController alloc] 
 initWithNibName：@MyViewControllerbundle：nil]; 
} 
 
 [self.navigationController 
 pushViewController：self.myViewController animated：YES]; 
  

在MyViewController的方法中，我放置了断点和日志消息以查看发生了什么：

   - （id）initWithNibName：（NSString *）nibNameOrNil bundle：（NSBundle *）nibBundleOrNil {
 
 if self = [super initWithNibName：nibNameOrNil bundle：nibBundleOrNil]）{
 NSLog（@initWithNibName\\\
）; 
} 
 
 return self; 
} 
 
  - （void）viewDidLoad {
 
 [super viewDidLoad]; 
 NSLog（@viewDidLoad\\\
）; 
} 
  

预期结果 b

调用 -initWithNibName 和 -viewDidLoad 方法，并显示myViewController的视图。

$ b

观察结果

只有 -initWithNibName 被调用，视图不显示。

我错过了什么？任何人都可以推荐任何东西检查？ （特别是在非常不透明的Interface Builder工具中）。

解决方案

好，我有一个部分答案 - 也许大师可以解释一些更多。问题是：

  [self.navigationController pushViewController：myViewController animated：YES]; 
  

更仔细地看，在这种情况下 self.navigationController



如果我发送：

<$> p $ p> [self.view addSubview：self.myViewController.view];


然后视图出现， -viewDidLoad 调用。

我不完全确定为什么 self.navigationController 没有设置在这个实例 - 我可以想到的是 self 是 UIViewController 的子类，而不是 UITableViewController （ pushViewController 代码来自）。

此外，默认允许消息去nil似乎是一个糟糕的主意，尽管这些答案不同。另请参阅我的问题此处。

最后编辑：

我实际上后（给myViewController是模态）是：

  [self presentModalViewController：myViewController animated：YES]; 
  

感谢大家的帮助。

Being new to Cocoa, I'm having a few issues with Interface Builder, UIViewController and friends.

I have a UIViewController subclass with a UIView defined in a xib, and with the controller's view outlet connected to the view. The xib's "file's owner" is set as myViewcontroller subclass.

In this one instance, the following code to load the controller/view (from the main view controller) doesn't work as expected:

if ( self.myViewController == nil )
{
    self.myViewController = [[MyViewController alloc]
        initWithNibName:@"MyViewController" bundle:nil];
}

[self.navigationController 
    pushViewController:self.myViewController animated:YES];

In MyViewController's methods, I have placed breakpoints and log messages to see what is going on:

-(id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {

    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        NSLog(@"initWithNibName\n");
    }

    return self;
}

-(void)viewDidLoad {

    [super viewDidLoad];
    NSLog(@"viewDidLoad\n");
}

Expected result

Both -initWithNibName and -viewDidLoad methods are called, and myViewController's view is displayed.

Observed result

Only -initWithNibName is called, the view is not displayed.

Have I missed something? Can anyone recommend anything to check? (Particularly in the wondrously opaque Interface Builder tool).

解决方案

Ok, I have a partial answer - maybe the gurus can explain some more. The problem is:

[self.navigationController pushViewController:myViewController animated:YES];

Looking more closely, in this case self.navigationController is nil - so the push message is going no-where.

Instead, if I send:

[self.view addSubview:self.myViewController.view];

Then the view appears and -viewDidLoad is called.

I'm not entirely sure why self.navigationController is not set in this instance - the only thing I can think of is that self is a subclass of UIViewController rather than UITableViewController (where the pushViewController code came from).

Also, silently allowing messages to go to nil seems like a bad idea, although these answers say otherwise. See also my question here.

Final edit:

Answers in comments below, I've realised the display function that I was actually after (given myViewController is modal) is:

[self presentModalViewController:myViewController animated:YES];

Thanks everyone for their helpful responses.

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