iOS-Runtime的那些事...编辑中....

Runtime-iOS的黑魔法，还是很好玩的，消息机制、方法替换简单记录了一点，持续更新....

1.方法替换

在类load方法中，替换系统方法

+ (void)load{

    Method oldColorMethod = class_getInstanceMethod([self class], @selector(setBackgroundColor:));

    Method newColorMethod = class_getInstanceMethod([self class], @selector(xg_setBackgroundColor:));
    ///交换方法
    ///调用系统的setBackgroundColor方法就会执行xg_setBackgroundColor方法
    method_exchangeImplementations(oldColorMethod, newColorMethod);
}
- (void)xg_setBackgroundColor:(UIColor *)color{
    ///在此方法中不要调用系统的setBackgroundColor方法，防止循环引用
    [self xg_setBackgroundColor:color];
}

2.动态生成属性

- (void)setNamexg:(NSString *)namexg{
    objc_setAssociatedObject(self, "namexg", namexg, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSString *)namexg{
    return objc_getAssociatedObject(self, "namexg");
}

3.字典转模型的实现

#import "NSObject+xgDictionary.h"
#import <objc/runtime.h>

@implementation NSObject (xgDictionary)
+ (instancetype)xg_modelKeyValues:(NSDictionary *)dicData{
    id model = [[self alloc]init];
    unsigned int count = ;
    ///返回类的所有属性和变量
    Ivar *ivarsA = class_copyIvarList(self, &count);
    for (int i = ; i < count; i ++) {
        Ivar iv = ivarsA[i];
        NSString *ivarName = [NSString stringWithUTF8String:ivar_getName(iv)];
        ivarName = [ivarName substringFromIndex:];
        id value = dicData[ivarName];
        [model setValue:value forKeyPath:ivarName];
    }
    return model;
}
@end