這個篇幅我們繼續研究Runtime,這裡給大家介紹Runtime的API

• Working with Classes
• Adding Classes
• Instantiating Classes
• Working with Instances
• Obtaining Class Definitions
• Working with Instance Variables
• Associative References
• Sending Messages
• Working with Methods
• Working with Libraries
• Working with Selectors
• Working with Protocols
• Working with Properties
• Using Objective-C Language Features
• Class-Definition Data Structures
• Instance Data Types
• Boolean Value
• Associative References
• Constants

• objc_系列函式關注於巨集觀使用,如類與協議的空間分配,註冊,登出等操作

• class_系列函式關注於類的內部,如例項變數,屬性,方法,協議等相關問題

• objcet_系列函式關注於物件的角度,如例項變數

• method_系列函式關注於方法內部,如果方法的引數及返回值型別和方法的實現

• property_系類函式關注與屬性*內部,如屬性的特性等

• protocol_系類函式關注與協議相關

• ivar_xxx函式關注與例項變數的東西

• sel_xxx主要討論關於方法編號相關的東西

• imp_xxx主要討論關於方法實現相關的

下面我們來玩一下這些常用的api

//交換方法
        Method m1 = class_getInstanceMethod(self, @selector(viewWillAppear:));
        Method m2 = class_getInstanceMethod(self, @selector(tz_viewWillAppear:));        
        method_exchangeImplementations(m1, m2);
// 關聯屬性
- (void)setViewColor:(NSString *)viewColor{

    objc_setAssociatedObject(self, &associatedObjectKey, @"addProperty", OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (NSString *)viewColor{
    return objc_getAssociatedObject(self, &associatedObjectKey);
}

 /// 建立一類對
    Class TZCat = objc_allocateClassPair([NSObject class], "TZCat", 0);

    /// 新增例項變數
    // const char* types= "
 
[email protected]:"
    NSString* name = @"name";

    class_addIvar(TZCat, name.UTF8String, sizeof(id), log2(sizeof(id)), @encode(id));

    // 新增方法
    class_addMethod(TZCat, @selector(hunting), (IMP)hunting, "[email protected]:");

    /// 註冊類
    objc_registerClassPair(TZCat);

    // 建立例項物件
    id cat = [[TZCat alloc] init];
    [cat setValue:@"Tom" forKey:@"name"];
    NSLog(@"name = %@", [cat valueForKey:name]);

    /// 方法呼叫
    [cat performSelector:@selector(hunting)];

  // 獲取成員變數列表
    unsigned int count = 0;
    Ivar* ivars = class_copyIvarList([self class], &count);

    for (int i = 0; i < count; i++) {
        Ivar var = ivars[i];
        const char* name = ivar_getName(var);
        NSString* key = [NSString stringWithUTF8String:name];
        id value = [self valueForKey:key];
        [aCoder encodeObject:value forKey:key];
    }

    free(ivars);

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