在iOS上，当ViewController的视图设置为我的UIView子类时，为什么不存在这样的属性？

If a subclass is defined as MyView that subclasses UIView, and in the Interface Builder, the view is clicked on, and the Custom Class is already set to MyView.

如果子类被定义为子类UIView的MyView,并且在Interface Builder中,则单击视图,并且自定义类已设置为MyView。

But in ViewController's viewDidLoad,

但是在ViewController的viewDidLoad中,

 self.view.foo = ... ;

will create a compile error that says foo is not a property of UIView. I then print out the class of self.view:

将创建一个编译错误,说foo不是UIView的属性。然后我打印出self.view类:

NSLog(@"Class of view is %@", NSStringFromClass([self.view class]));

and sure enough, it prints out MyView. Also, not only the first line will not compile, Xcode will not "auto complete" the word "foo" as well. But clearly, the class prints out no as UIView but is MyView, and in my class definition of MyView, I did say:

果然,它打印出MyView。此外,不仅第一行不会编译,Xcode也不会“自动完成”单词“foo”。但显然,该类打印出的不是UIView,而是MyView,在我的MyView类定义中,我说过:

@property (nonatomic, strong) NSMutableArray *foo;

in the interface .h file, and also in the implementation .m file:

在接口.h文件中,以及实现.m文件中:

@synthesize foo;

and MyView.h is imported in ViewController.h as well. Why is this so and how to fix this?

MyView.h也在ViewController.h中导入。为什么会如此以及如何解决这个问题?

1 个解决方案

#1

Your UIViewController doesn't know that its view is meant to be an instance of your MyView subclass.

你的UIViewController不知道它的视图是你的MyView子类的一个实例。

You'll need to cast it

你需要施展它

MyView *myView = (MyView *)self.view;
myView.foo = @"Whatever";

If you want to simplify this, you can also subclass UIViewController and then just always reference self.myView in your MyViewController subclasses instead of self.view:

如果你想简化这个,你也可以继承UIViewController,然后总是在你的MyViewController子类中引用self.myView而不是self.view:

@interface MyViewController : UIViewController

@property (nonatomic, strong) MyView *myView;

@end


@implementation MyViewController
@synthesize myView;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
            self.myView = (MyView *)self.view;
    }
    return self;
}
@end

#1