获取属性列表

-(void)dome{    unsigned int numIvars; //成员变量个数    Ivar *vars = class_copyIvarList(NSClassFromString(@"UIAlertAction"), &numIvars);    //Ivar *vars = class_copyIvarList([UIView class], &numIvars);        NSString *key=nil;    for(int i = 0; i < numIvars; i++) {                Ivar thisIvar = vars[i];        key = [NSString stringWithUTF8String:ivar_getName(thisIvar)];  //获取成员变量的名字        NSLog(@"variable name :%@", key);        key = [NSString stringWithUTF8String:ivar_getTypeEncoding(thisIvar)]; //获取成员变量的数据类型        NSLog(@"variable type :%@", key);    }    free(vars);}//因为ivar_getName得到的是一个带有下划线的名字，去掉下划线看起来更漂亮-(NSString *)delLine:(NSString *)string{    if ([string hasPrefix:@"_"]) {        return [string substringFromIndex:1];    }    return string;}