ios 如何访问私有变量

写一个TestObject类 代码如下
TestObject.h

#import <Foundation/Foundation.h>

@interface TestObject : NSObject

@property (copy, nonatomic) NSString *name;
@property (copy, nonatomic) NSString *sex;

@end

TestObject.m

#import "TestObject.h"
#import <objc/runtime.h>

@interface TestObject()

@property (copy, nonatomic) NSString *privateName;
@property (copy, nonatomic) NSString *privateSex;

@end

@implementation TestObject


@end

方式一 使用KVC方式

    TestObject *obj = [TestObject new];
    [obj getIvars];
    
    [obj setValue:@"123" forKey:@"privateName"];
    NSLog(@"privateName:%@", [obj valueForKey:@"privateName"]);

方式二：
假如我们不知TestObject有哪些属性，所以我们可以利用RunTime获取所有属性

- (void)getIvars
{
    unsigned int count = 0;
    // 拷贝出所胡的成员变量列表
    Ivar *ivars = class_copyIvarList([self class], &count);
    
    for (int i = 0; i<count; i++) {
        // 取出成员变量
        Ivar ivar = ivars[i];
        // 打印成员变量名字
        NSLog(@"%s---", ivar_getName(ivar));
        // 打印成员变量的数据类型
        NSLog(@"%s---", ivar_getTypeEncoding(ivar));
        NSLog(@"---------------------------------------");
    }
    // 释放
    free(ivars);
}

假如我们要访问privateName属性，代码如下

   unsigned int count = 0;
    Ivar *ivars = class_copyIvarList([TestObject class], &count);
    //对私有变量的更改
    Ivar privateNameIvar = ivars[2];
    object_setIvar(obj, privateNameIvar, @"456");
    NSString *privateName = object_getIvar(obj, privateNameIvar);
    NSLog(@"privateName : %@",privateName);

Demo：https://github.com/destinyzhao/GetAttributesAndMethod