iPhone UIViewController init 方法没有被调用

Question

我对 iPhone 编程非常陌生，并且遇到了一些奇怪的情况。对于下面的类，init 方法永远不会被调用——我有一个 NSLog 函数，它应该告诉我 init 何时执行。相关代码如下:

@interface MyViewController : UIViewController {
}
@end

@implementation MyViewController
- (id) init
{
    NSLog(@"init invoked");
    return self;
}
@end

关于我做错了什么有什么想法吗——如果有的话？希望我提供了足够的信息。

谢谢。

Answer 1

如果您使用 Storyboard，将调用 initWithCoder:。引用文件说:

If your app uses a storyboard to define a view controller and its associated views, your app never initializes objects of that class directly. Instead, view controllers are either instantiated by the storyboard—either automatically by iOS when a segue is triggered or programmatically when your app calls the storyboard object’s instantiateViewControllerWithIdentifier: method. When instantiating a view controller from a storyboard, iOS initializes the new view controller by calling its initWithCoder: method instead. iOS automatically sets the nibName property to a nib file stored inside the storyboard.

initWithCoder: 方法不是 .m 文件默认模板的一部分，因此您必须将自己添加到 UIViewController 子类中:

- (id)initWithCoder:(NSCoder *)aDecoder {

    self = [super initWithCoder:aDecoder];

    if (self) {
        // Custom initialization
        NSLog(@"Was called...");
    }

    return self;
}

无需从代码中删除 initWithNibName:bundle:，但无论如何都不会调用它。