iOS-Runtime的那些事...編輯中....

Runtime-iOS的黑魔法，還是很好玩的，消息機制、方法替換簡單記錄了一點，持續更新....

1.方法替換

在類load方法中，替換系統方法

+ (void)load{
    
    Method oldColorMethod = class_getInstanceMethod([self class], @selector(setBackgroundColor:));
    
    Method newColorMethod = class_getInstanceMethod([self class], @selector(xg_setBackgroundColor:));
    ///交換方法
    ///調用系統的setBackgroundColor方法就會執行xg_setBackgroundColor方法
    method_exchangeImplementations(oldColorMethod, newColorMethod);
}
- (void)xg_setBackgroundColor:(UIColor *)color{
    ///在此方法中不要調用系統的setBackgroundColor方法，防止迴圈引用
    [self xg_setBackgroundColor:color];
}

2.動態生成屬性

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

3.字典轉模型的實現

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

@implementation NSObject (xgDictionary)
+ (instancetype)xg_modelKeyValues:(NSDictionary *)dicData{
    id model = [[self alloc]init];
    unsigned int count = 0;
    ///返回類的所有屬性和變數
    Ivar *ivarsA = class_copyIvarList(self, &count);
    for (int i = 0; i < count; i ++) {
        Ivar iv = ivarsA[i];
        NSString *ivarName = [NSString stringWithUTF8String:ivar_getName(iv)];
        ivarName = [ivarName substringFromIndex:1];
        id value = dicData[ivarName];
        [model setValue:value forKeyPath:ivarName];
    }
    return model;
}
@end