亲子关系-我的父母认识自己的孩子，但是孩子不知道应该何时父母

Question

我正在开发一个具有书本对象（RSEBook）的应用程序，每个书本对象都有一个NSMutableArray关键字对象（Keyword）。 书中的可变数组称为“关键字”

将子项（关键字）添加到父项数组的方法是：

-（void）addTag :(关键字*）word {

[关键字addObject：word];

[word setParent：self];

}

但是，在Document.m中调用此方法时：

-（IBAction）createKeyword：（id）sender {

NSWindow * w = [tabView窗口];

 BOOL editingEnded = [w makeFirstResponder:w]; if(!editingEnded) { NSBeep(); return; } Keyword *k = [[Keyword alloc] init]; //Create a new keyword instance id current = [booksAC selectedObjects]; //NSArray of the selectedObjects (there will only ever be one object in the array as my table view hasn't got multi selection RSEBook *currBook = [current objectAtIndex:0]; //Get that object into currBook if (!currBook) { //Check that currBook = something NSLog(@"current is nil"); } 

[currBook addTag:k];             //Add the object k as a tag to currBooks NSMutableArray 'keywords' this SHOULD set the parent, but it dosent (defined in RSEBook.h)


NSLog(@"The keywords parent: %@" ,[k parent]);  // this is always null for some reason
NSLog(@"parents keywords: %@", [currBook keywords]);  // this returns what I expect, a list of the books keywords