Question

I m attending the course of IOS development on itunesU (from Stanford University).
And i got a big doubt about an attribute of a class created in one of this lectures. Let me explain with some code :

我有“面对面意见”这一类,其使命是求取一面,该类的一个属性是“替代”,这是必须执行面对面意见的一个目标。

这里是接口守则:

#import <UIKit/UIKit.h>
@class FaceView;

@protocol FaceViewDelegate
-(float)smileForFaceView:(FaceView *)requestor;
@end

@interface FaceView : UIView {
    id <FaceViewDelegate> delegate;
    CGFloat scale;
}

@property CGFloat scale;
@property (assign) id <FaceViewDelegate> delegate;

@end

I can t understand why delegate is not a pointer to object, but directly an object. Someone could kindly tell me more about this implementation choiche? is this correct ? why ? Thank you so much!

Answer 1

这是物体的指点。 <代码>id已经成为一个点。因此,当你宣布“<代码>id”的变数时,就不需要点数。因此,这些声明基本相同(即你可以完全以同样的方式使用我的IDObj和我的Obj):

// myIDObj and myObj are both pointers to objects
id myIDObj = [[NSObject alloc] init];
NSObject* myObj = [[NSObject alloc] init];

Answer 2

www.un.org/Depts/DGACM/index_french.htm <代码>id 类型定义为:

typedef struct objc_object {
    Class isa;
} *id;

因此,它已经成为一个要点。

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