如何在objective-c中实现"swset的快速"？

Question

Swift(来自http://www.raywenderlich.com/发布的"教程的iOS动画:第12章" ):

let photoLayer = CALayer()

@IBInspectable
  var image: UIImage! {
    didSet {
      photoLayer.contents = image.CGImage
    }
}

如何在objective-c中实现上述语法？我知道只设置photoLayer的属性和图像如下:

@property (strong, nonatomic) CALayer *photoLayer;
@property (strong, nonatomic) IBInspectable UIImage *image;

但我不知道如何didset{...}使用objective-c语法实现部件,请帮忙!

Answer 1

覆盖setter并自己实现setter.

- (void)setImage:(UIImage*)image {
    _image = image;
    photoLayer.contents = image.CGImage
}