问题描述
unsigned int count;//在运行时创建继承自NSObject的People类Class People = objc_allocateClassPair([NSObject class], 'People', 0);//完成People类的创建objc_registerClassPair(People);objc_property_attribute_t type = {'T', '@'NSString''};objc_property_attribute_t attribute2 = {'N',''};//value无意义时通常设置为空objc_property_attribute_t ownership = { 'C', '' };objc_property_attribute_t backingivar = { 'V', '_pro'};objc_property_attribute_t attrs[] = {type,attribute2, ownership, backingivar};//向People类中添加名为pro的属性,属性的4个特性包含在attributes中BOOL y = class_addProperty(People, 'pro', attrs, 4);NSLog(@'%d',y);//创建People对象p1id p1 = [[People alloc]init];objc_property_t * properties = class_copyPropertyList(People, &count);for (int i = 0; i<count; i++) { NSLog(@'属性的名称为 : %s',property_getName(properties[i])); NSLog(@'属性的特性字符串为: %s',property_getAttributes(properties[i]));}//请问怎么为pro赋值?
问题解答
回答1：- (void)dynamic2{unsigned int count;//在运行时创建继承自NSObject的People类 Class People = objc_allocateClassPair([NSObject class], 'People', 0);NSString *proName = @'pro';class_adpar(People, [proName cStringUsingEncoding:NSUTF8StringEncoding], sizeof(NSString *), log2(sizeof(NSString*)), @encode(NSString*)); //完成People类的创建 objc_registerClassPair(People); objc_property_attribute_t type = {'T', '@'NSString''}; objc_property_attribute_t attribute2 = {'N',''};//value无意义时通常设置为空 objc_property_attribute_t ownership = { 'C', '' }; objc_property_attribute_t backingivar = { 'V', [proName cStringUsingEncoding:NSUTF8StringEncoding]}; objc_property_attribute_t attrs[] = {type,attribute2, ownership, backingivar};//向People类中添加名为pro的属性,属性的4个特性包含在attributes中 if (class_addProperty(People, [proName cStringUsingEncoding:NSUTF8StringEncoding], attrs, 4)) {NSString *s = [NSString stringWithFormat:@'set%@:',[proName capitalizedString]];//添加get和set方法class_addMethod([People class], NSSelectorFromString(proName), (IMP)getter, '@@:');class_addMethod([People class], NSSelectorFromString(s), (IMP)setter, 'v@:@'); }//创建People对象p1 id p1 = [[People alloc]init];objc_property_t * properties = class_copyPropertyList(People, &count); for (int i = 0; i<count; i++) {NSLog(@'属性的名称为 : %s',property_getName(properties[i]));NSLog(@'属性的特性字符串为: %s',property_getAttributes(properties[i])); }[p1 setValue:@'111' forKey:@'pro']; NSLog(@'%@', [p1 valueForKey:@'pro']);}id getter(id self1, SEL _cmd1) { NSString *key = NSStringFromSelector(_cmd1); Ivar ivar = class_getInstanceVariable([self1 class], [key cStringUsingEncoding:NSUTF8StringEncoding]); NSString *s = object_getIvar(self1, ivar); return s;}void setter(id self1, SEL _cmd1, id newValue) { //移除set NSString *key = [NSStringFromSelector(_cmd1) stringByReplacingCharactersInRange:NSMakeRange(0, 3) withString:@'']; //首字母小写 NSString *head = [key substringWithRange:NSMakeRange(0, 1)]; head = [head lowercaseString]; key = [key stringByReplacingCharactersInRange:NSMakeRange(0, 1) withString:head]; //移除后缀 ':' key = [key stringByReplacingCharactersInRange:NSMakeRange(key.length - 1, 1) withString:@''];Ivar ivar = class_getInstanceVariable([self1 class], [key cStringUsingEncoding:NSUTF8StringEncoding]); object_setIvar(self1, ivar, newValue);回答2：
按照你添加的方法, 这个也是可以的
SEL setter = NSSelectorFromString(@'setPro:'); SEL getter = NSSelectorFromString(@'pro'); if ([p1 respondsToSelector:setter] && [p1 respondsToSelector:getter]) {[p1 performSelector:setter withObject:@'NBA'];id d = [p1 performSelector:getter withObject:nil];NSLog(@'d,%@',d); }回答3：
都是大神啊，求教这些语法我从来没学过，我常见的是什么Objective-C 最常用的那种语法。请问这些语法是属于什么知识呢？在什么地方常用呢？多谢大大解答啊~ 我要掌握这些看着很酷的语法~~~~
