ACM_Someone like you

#import <Foundation/Foundation.h>

@interface MethodDetailMusic : NSObject
{
    @public NSString *publicStr;
}

@property (nonatomic, strong) NSString * img_url;
@property (nonatomic, strong) NSString * amount;
@property (nonatomic, strong) NSString * time;
@property (nonatomic, strong) NSString * title;
@property (nonatomic, strong) NSString * url;
@property (nonatomic, strong) NSString * method_id;

- (void)initPrivateString;

@end
#import "MethodDetailMusic.h"

@interface MethodDetailMusic()
{
    @private NSString *specialPrivateString;
}

//聲明一個私有方法
- (void)createPrivateFunction;

@end

@implementation MethodDetailMusic

- (void)createPrivateFunction
{//TODO:實施一個私有方法
    
}

- (void)initPrivateString
{
    if (!specialPrivateString) {
        specialPrivateString = @"我是私有變量";
    }
    NSLog(@"%@",specialPrivateString);
}

- (void)viewDidLoad {
    [super viewDidLoad];
    [self test1];//調用
}

- (void)test1
{
    MethodDetailMusic *music = [[MethodDetailMusic alloc]init];
    music.title = @"haha";
    [music initPrivateString];//這里 調用類本身的實例方法有一處日志
    
    NSLog(@"\n title:%@ \n",music.title);
    
    //可修改: KVC 鍵值編碼 修改私有變量
    [music setValue:@"修改私有變量的值" forKey:@"specialPrivateString"];
    [music initPrivateString];
    
    //可讀取 #import <objc/runtime.h>  獲取私有變量
    //定義一個實例變量 privateString
    Ivar privateString = class_getInstanceVariable([music class], "specialPrivateString");
    NSString *privateStr = object_getIvar(music, privateString);
    NSLog(@"打印私有變量===%@",privateStr);
    
    music->publicStr = @"我是公有變量";
    
    [self viewControllerPrivateFunc];

}

log 日志:

2016-08-17 14:36:23.860 LearningTheroyDemo[10907:5802354] 我是私有變量

2016-08-17 14:36:23.860 LearningTheroyDemo[10907:5802354] title:haha 

2016-08-17 14:36:23.860 LearningTheroyDemo[10907:5802354] 修改私有變量的值

2016-08-17 14:36:23.861 LearningTheroyDemo[10907:5802354] 打印私有變量===修改私有變量的值