自定义类Honzon，一个私有成员变量test和一个打印方法logTest
@interface Honzon : NSObject
- (void)logTest;
@end
@interface Honzon ()
@property(nonatomic, copy)NSString *test;
@end
@implementation Honzon
- (void)logTest {
NSLog(@"test: %@", self.test);
}
@end
KVC
Honzon *h1 = [Honzon new];
[h1 setValue:@"h1 test" forKey:@"test"];
[h1 logTest];
//-> test: h1 test
调用私有方法
通过OC的运行时，调用私有变量的setter方法
//消息发送
Honzon *h2 = [Honzon new];
if ([h2 respondsToSelector:@selector(setTest:)]) {
[h2 performSelector:@selector(setTest:) withObject:@"h2 test"];
NSLog(@"%@",[h2 performSelector:@selector(test)]);
//-> h2 test
// objc_msgSend(h2,@selector(setTest:),@"h2 test");
// [h2 logTest];
}
[h2 logTest];
//-> test: h2 test
当然也可以获取方法列表去循环查找
Ivar
先取得ivar，然后通过object_setIvar修改成员变量的值
//runtime 获取ivar
// 获取类的所有成员变量
Honzon *h3 = [Honzon new] ;
unsigned int count = 0;//count记录变量的数量
Ivar *members = class_copyIvarList([h3 class], &count);
for (NSUInteger i = 0; i < count; i++) {
Ivar ivar = members[i];
// 取得属性名并转成字符串类型
const char *memberName = ivar_getName(ivar);
NSString *memberNameString = [NSString stringWithUTF8String:memberName];
if ([memberNameString isEqualToString:@"_test"]) {
// 修改属性值
object_setIvar(h3, ivar, @"h3 test");
break;
}
}
[h3 logTest];
free(members);
//-> test: h3 test
Honzon *h4 = [Honzon new] ;
Ivar _testNameIvar = class_getInstanceVariable([h4 class], "_test");
object_setIvar(h4, _testNameIvar, @"h4 test");
[h4 logTest];
//-> test: h4 test
NSValue包装结构体
自定义结构体
struct HZStruct {
int version;
char *name;
};
包装结构体
struct HZStruct hzStruct = {
.version = 0,
.name = "hzStruct"
};
NSValue *hz1 = [NSValue value:&hzStruct withObjCType:@encode(struct HZStruct)];
解包结构体
struct HZStruct hzStruct2;
[hz1 getValue:&hzStruct2];
NSLog(@"%d %s",hzStruct2.version,hzStruct2.name);
//-> 0 hzStruct
NSValue针对系统的部分结构体做了优化，比如valueWithRect，不用像自定义结构体这样
