Core数据保存问题：无法更新可变属性（NSArray）

本文介绍了Core数据保存问题：无法更新可变属性（NSArray）的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我在Core Data应用程式中有一个奇怪的问题。 我的应用程式中有三个实体，但今天我发现其中一个存在问题。我的问题实体叫做 Invoice ，它有很多属性，包括 Products 。它是NSDictionaries的NSArray编码（通过默认NSValueTransformer）。 一切正常 - 我创建我的发票，客户端，产品等。 但，当我从列表中选择发票，然后尝试修改其产品并点击保存按钮时，我的保存仅在我的应用获取 问题只在于我的产品数组 - 其余的（例如付款日期，客户等） b 我通过 传递发票 = [self.fetchedResultsController objectAtIndexPath：indexPath]; invoiceEditor.invoice = inv; 并保存我的数据（在我的 InvoiceEditor VC）： [self.invoice setValue：client forKey：@Client] // NSDictionary; [self.invoice setValue：products forKey：@Products] // NSDictionaries的NSArray; [self.invoice setValue：pmDate forKey：@PaymentDate] // NSDate; //其他属性 NSManagedObjectContext * context = self.invoice.managedObjectContext; NSError * error = nil; if（！[context save：& error]）{ NSLog（@Unresolved error％@，％@，error，[error userInfo]）; abort（）; Everythings保存直到被终止：客户端，产品，日期。} 解决方案 p>刚刚发现问题。从模型对象实现指南： 如果有一个类的mutable和immutable版本，如NSArray和NSMutableArray - 你通常应该将get访问器的返回值声明为不可变对象，即使模型内部使用了一个可变对象。 而我的产品数组实际上是一个 NSMutableArray 实例。我通过复制 products 解决了（所以我将mutable数组转换为immutable数组）。现在它的工作。 :)我不需要开始赏金... I have a strange problem in my Core Data app.I have three entities in my app, but today I found a problem with one of them. My problematic entity is called Invoice and it has many attributes, including Products. It's encoded NSArray of NSDictionaries (via default NSValueTransformer).Everything works fine - i create my invoice, its client, its products, etc. Everything works.But, when I choose my invoice from a list and then try to edit its products and click 'Save' button, my save works only until my app gets terminated.The problem is only with my products array - the rest (e.g. payment date, client etc.) saves.What am I doingI pass my Invoice object viaNSManagedObject *inv = [self.fetchedResultsController objectAtIndexPath:indexPath];invoiceEditor.invoice = inv;And save my data (in my InvoiceEditor VC):[self.invoice setValue:client forKey:@"Client"] // NSDictionary;[self.invoice setValue:products forKey:@"Products"] // NSArray of NSDictionaries;[self.invoice setValue:pmDate forKey:@"PaymentDate"] // NSDate;// other attributesNSManagedObjectContext *context = self.invoice.managedObjectContext;NSError *error = nil;if (![context save:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort();}Everythings saves until being terminated: client, products, dates. But only products are 'reseted' after termination.Anybody? 解决方案 Just found the problem. From Model Object Implementation Guide: If there are mutable and immutable versions of a class you use to represent a property—such as NSArray and NSMutableArray—you should typically declare the return value of the get accessor as an immutable object even if internally the model uses a mutable object.And my products array was actually a NSMutableArray instance. I solved it by copying products (so I converted mutable array to immutable array). Now it works. :) And I didn't need to start the bounty... 这篇关于Core数据保存问题：无法更新可变属性（NSArray）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！