iVar getter / 方法同名？ (iVar getter / method with same name?)

問題描述

iVar getter / 方法同名？ (iVar getter / method with same name?)

誰能解釋這裡發生了什麼，乍一看，我認為這是不好的做法。我的問題是：在下面的示例中，我是使用 ‑(id)model 為模型創建一個新的 getter（即覆蓋 @property 的原始 getter），還是只是用這個新的同名方法掩蓋 @property getter？< /p>

@implementation PlanetController
@synthesize model;
@synthesize planetLabel_01;
@synthesize planetLabel_02;
@synthesize planetLabel_03;

‑ (id)model {
    if(!model) {
        PlanetModel *tempModel = [[PlanetModel alloc] init];
        [self setModel:tempModel];
        [tempModel release];
    }
    return model;
}

這有意義嗎？

加里。

參考解法

方法 1:

What you are doing is not bad practice. You are not overwriting or masking anything. @synthesize will only synthesize what's needed. In this case, the setter.

方法 2:

As everybody else has said, that's absolutely fine. Your model method is used instead of the synthesized one.

However be cautious: you have implemented a method that is not atomic so your property should have the following declaration:

@property (nonatomic, retain) id model;

otherwise it is lying about its implementation.

方法 3:

You've implemented your own accessor for the model property. That's a perfectly valid thing to do. You can verify that it's your implementation that is executed when you do either aPlanetController.model or [aPlanetController model].

方法 4:

It looks OK to me, but you can always check it by printing out the method names at run‑time.

#import <objc/objc.h>
#import <objc/runtime.h>
#include "SFUtility.h"

/*!
 @abstract spits out the objc/runtime.h information for the class
 */
void SFInvestigateOBJC(id obj) {


    unsigned int total_method_count = 0;
    Method * method_list = class_copyMethodList(object_getClass([obj class]), &total_method_count);
    @try
    {
        SFLog(@"ClassName: %s", class_getName(object_getClass([obj class])));
        SFLog(@"ClassName: %@", [obj class]);
        uint method_counter = 0;
        for (method_counter = 0; method_counter < total_method_count; method_counter++)
        {
            Method method = method_list[method_counter];
            // check if method the KVC getter you are interested in
            SFLog(@"Method: %s", sel_getName(method_getName(method)));
        }
        NSDictionary *props = [[obj entity] propertiesByName];
        for (NSString *s in [props allKeys]) {
            SFLog(@"KVC: %@", s);
        }
    } @catch (NSException *e) {
        SFError(@"Exception: %@", [e description]);
    }

    @try {
        SFLog(@"Entity: %@",[[obj entity] name]);
        SFLog(@"EntityClassName: %@", [[obj entity] managedObjectClassName]);
    } @catch (NSException * e) {
        SFError(@"Exception: %@", [e description]);
    }

}

(by fuzzygoat、hooleyhoop、JeremyP、Costique、Stephen Furlani)

參考文件

1. iVar getter / method with same name? (CC BY‑SA 3.0/4.0)