struct objc_class {
 Class isa;//指針，顧名思義，表示是一個什么，
 //實例的isa指向類對象，類對象的isa指向元類

#if !__OBJC2__
 Class super_class; //指向父類
 const char *name; //類名
 long version;
 long info;
 long instance_size
 struct objc_ivar_list *ivars //成員變量列表
 struct objc_method_list **methodLists; //方法列表
 struct objc_cache *cache;//緩存
 //一種優(yōu)化，調(diào)用過的方法存入緩存列表，下次調(diào)用先找緩存
 struct objc_protocol_list *protocols //協(xié)議列表
 #endif
} OBJC2_UNAVAILABLE;
/* Use `Class` instead of `struct objc_class *` */

#import <objc/runtime.h>

// 輸出類的一些信息
- (void)logInfo {
 unsigned int count;// 用于記錄列表內(nèi)的數(shù)量，進(jìn)行循環(huán)輸出

 // 獲取屬性列表
 objc_property_t *propertyList = class_copyPropertyList([self class], &count);
 for (unsigned int i = 0; i < count; i++) {
 const char *propertyName = property_getName(propertyList[i]);
 NSLog(@"property --> %@", [NSString stringWithUTF8String:propertyName]);
 }

 // 獲取方法列表
 Method *methodList = class_copyMethodList([self class], &count);
 for (unsigned int i; i < count; i++) {
 Method method = methodList[i];
 NSLog(@"method --> %@", NSStringFromSelector(method_getName(method)));
 }

 // 獲取成員變量列表
 Ivar *ivarList = class_copyIvarList([self class], &count);
 for (unsigned int i; i < count; i++) {
 Ivar myIvar = ivarList[i];
 const char *ivarName = ivar_getName(myIvar);
 NSLog(@"Ivar --> %@", [NSString stringWithUTF8String:ivarName]);
 }

 // 獲取協(xié)議列表
 __unsafe_unretained Protocol **protocolList = class_copyProtocolList([self class], &count);
 for (unsigned int i; i < count; i++) {
 Protocol *myProtocal = protocolList[i];
 const char *protocolName = protocol_getName(myProtocal);
 NSLog(@"protocol --> %@", [NSString stringWithUTF8String:protocolName]);
 }
}

// 調(diào)用不存在的類方法時觸發(fā)，默認(rèn)返回NO，可以加上自己的處理后返回YES
+ (BOOL)resolveClassMethod:(SEL)sel;

// 調(diào)用不存在的實例方法時觸發(fā)，默認(rèn)返回NO，可以加上自己的處理后返回YES
+ (BOOL)resolveInstanceMethod:(SEL)sel;

// 將調(diào)用的不存在的方法重定向到一個其他聲明了這個方法的類里去，返回那個類的target
- (id)forwardingTargetForSelector:(SEL)aSelector;

// 將調(diào)用的不存在的方法打包成 NSInvocation 給你，自己處理后調(diào)用 invokeWithTarget: 方法讓某個類來觸發(fā)
- (void)forwardInvocation:(NSInvocation *)anInvocation;

@interface ViewController ()
@property (nonatomic, strong) UIButton *logBtn;

- (void)notHas;// 要調(diào)用的實例方法，沒有具體實現(xiàn)
@end

- (void)viewDidLoad {
 [super viewDidLoad];

 // 添加按鈕
 self.logBtn = [[UIButton alloc] initWithFrame:CGRectMake(100, 200, 100, 20)];
 [self.logBtn setTitle:@"測 試" forState:UIControlStateNormal];
 [self.logBtn setTitleColor:[UIColor lightGrayColor] forState:UIControlStateNormal];
 // 添加沒有實現(xiàn)的點(diǎn)擊事件
 [self.logBtn addTarget:self action:@selector(notHas) forControlEvents:UIControlEventTouchUpInside];
 [self.view addSubview:self.logBtn];

}

// 攔截對不存在的方法的調(diào)用
+ (BOOL)resolveInstanceMethod:(SEL)sel {
 NSLog(@"notFind!");
 // 給本類動態(tài)添加一個方法
 if ([NSStringFromSelector(sel) isEqualToString:@"notHas"]) {
 class_addMethod(self, sel, (IMP)runAddMethod, "v@:*");
 }
 // 注意要返回YES
 return YES;
}

// 要動態(tài)添加的方法，這是一個C方法
 void runAddMethod(id self, SEL _cmd, NSString *string) {
 NSLog(@"動態(tài)添加一個方法來提示");
}

 // 關(guān)聯(lián)對象
 static char associatedObjectKey;
 objc_setAssociatedObject(self, &associatedObjectKey, @"我就是要關(guān)聯(lián)的字符串對象內(nèi)容", OBJC_ASSOCIATION_RETAIN_NONATOMIC);
 NSString *theString = objc_getAssociatedObject(self, &associatedObjectKey);
 NSLog(@"關(guān)聯(lián)對象：%@", theString);

enum {
 OBJC_ASSOCIATION_ASSIGN = 0,
 OBJC_ASSOCIATION_RETAIN_NONATOMIC = 1, 
 OBJC_ASSOCIATION_COPY_NONATOMIC = 3,
 OBJC_ASSOCIATION_RETAIN = 01401,
 OBJC_ASSOCIATION_COPY = 01403 
};

//添加關(guān)聯(lián)對象
- (void)addAssociatedObject:(id)object{
 objc_setAssociatedObject(self, @selector(getAssociatedObject), object, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

//獲取關(guān)聯(lián)對象
- (id)getAssociatedObject{
 return objc_getAssociatedObject(self, _cmd);
}