ios - RestKit本地删除对象,依然出现在mapping中
<p><p>我正在为我的应用程序使用 RestKit 0.20.3。它具有离线模式,所以我必须将对象存储在本地核心数据中。</p>
<p>每当从服务器中删除某些对象时,它会以 JSON 格式发送 <code>deleted = true</code> 属性,我在与 <code>deletionPredicate</code> 的映射中处理该属性。
这是我的 map 。</p>
<pre><code>- (RKEntityMapping *)meetingsMapping {
RKEntityMapping *meetingsMapping = ;
meetingsMapping.setDefaultValueForMissingAttributes = NO;
meetingsMapping.deletionPredicate = ;
;
meetingsMapping.identificationAttributes = @[@"id"];
[meetingsMapping addAttributeMappingsFromDictionary:@{
@"id": @"id",
@"title": @"title",
@"start_date_human": @"start_date_human",
@"start_time_human": @"start_time_human",
@"finish_date_human": @"finish_date_human",
@"finish_time_human": @"finish_time_human",
@"lock": @"lock",
@"location": @"location",
@"sample": @"sample",
@"deleted": @"shouldBeDeleted",
@"created_at": @"created_at",
@"updated_at": @"updated_at",
@"follow_up_id": @"follow_up_id",
@"total_topics": @"total_topics",
}];
];
];
];
];
];
return meetingsMapping;
</code></pre>
<p>}</p>
<p>它运行良好,并且从本地 CoreData 中删除了属性。</p>
<p>问题是方法 <code>getObjectsAtPath</code> 仍然返回 <code>mappingResult</code> 参数中的所有对象。</p>
<pre><code>[ getObjectsAtPath:
parameters:nil
success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
KLog(@"%@", mappingResult.array); // It is returning all objects, not only non-deleted objects
completionHandler(mappingResult.array, nil);
}
failure:^(RKObjectRequestOperation *operation, NSError *error) {
completionHandler(nil, error);
}];
</code></pre>
<p>假设如果删除了 20 个对象中的 5 个,则 <code>mappingResult.array</code> 返回 20 条记录而不是 15 条。删除的 5 条记录没有数据。当我记录 <code>mappingResult.array</code> 时,前 5 条记录打印如下:</p>
<pre><code>2014-03-27 13:10:14.105 MeetingKing W restkit.network.core_data:RKManagedObjectRequestOperation.m:125 Unable to refetch managed object <DBMeetings: 0xc1cb820> (entity: DBMeetings; id: 0xc1a6a60 <x-coredata://7B9FC7F6-C0E9-4DF5-91AC-D7C49F54B4F5/DBMeetings/t2915CF2E-2D7D-4E29-8B39-B1C51151809410> ; data: <fault>): the object has a temporary managed object ID.
2014-03-27 13:10:14.105 MeetingKing W restkit.network.core_data:RKManagedObjectRequestOperation.m:125 Unable to refetch managed object <DBMeetings: 0xc5b2ed0> (entity: DBMeetings; id: 0xc5d1110 <x-coredata://7B9FC7F6-C0E9-4DF5-91AC-D7C49F54B4F5/DBMeetings/t2915CF2E-2D7D-4E29-8B39-B1C51151809416> ; data: <fault>): the object has a temporary managed object ID.
2014-03-27 13:10:14.106 MeetingKing W restkit.network.core_data:RKManagedObjectRequestOperation.m:125 Unable to refetch managed object <DBMeetings: 0xc58b6a0> (entity: DBMeetings; id: 0xc5d3de0 <x-coredata://7B9FC7F6-C0E9-4DF5-91AC-D7C49F54B4F5/DBMeetings/t2915CF2E-2D7D-4E29-8B39-B1C51151809417> ; data: <fault>): the object has a temporary managed object ID.
2014-03-27 13:10:14.106 MeetingKing W restkit.network.core_data:RKManagedObjectRequestOperation.m:125 Unable to refetch managed object <DBMeetings: 0xc5b50e0> (entity: DBMeetings; id: 0xc5d4af0 <x-coredata://7B9FC7F6-C0E9-4DF5-91AC-D7C49F54B4F5/DBMeetings/t2915CF2E-2D7D-4E29-8B39-B1C51151809419> ; data: <fault>): the object has a temporary managed object ID.
2014-03-27 13:10:14.107 MeetingKing W restkit.network.core_data:RKManagedObjectRequestOperation.m:125 Unable to refetch managed object <DBMeetings: 0xc1ed5a0> (entity: DBMeetings; id: 0xc1c84e0 <x-coredata://7B9FC7F6-C0E9-4DF5-91AC-D7C49F54B4F5/DBMeetings/t2915CF2E-2D7D-4E29-8B39-B1C51151809422> ; data: <fault>): the object has a temporary managed object ID.
</code></pre>
<p>如果我 checkin 数据库,则只有 15 条记录。没关系。</p>
<p>如果我明确地从数据库中获取,它只返回 15 条记录,没关系</p>
<p>但是在<code>getObjectsAtPath</code>回调中,<code>mappingResult.array</code>参数返回20条记录。那不行。 :(</p>
<p>问题是 <code>mappingResult.array</code> 的 <code>count</code> 变成 20,而我的 <code>UITableView</code> 显示 20 行,其中 5 行没有数据。</p>
<p>RestKit 是否有任何其他回调可以准确返回 15 条记录,这样我就不必从数据库中显式获取记录?</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p><code>mappingResult</code> 正在返回被映射的对象,这是它应该做的。一些项目随后被删除的事实并没有改变这一点 - 实际上,您拥有所需的所有信息,因为您知道所有已映射的对象以及哪些对象因此被删除。</p>
<p>简单的解决方案是使用 <code>NSFetchedResultsController</code> 来获取表格 View 的数据。它将正确处理更新、插入和删除,您不需要做额外的工作。</p>
<p>或者,您需要迭代 <code>mappingResult.array</code> 并过滤掉已删除的项目。最好的验证方法是使用支票:</p>
<pre><code>if (item.isDeleted || item.managedObjectContext == nil) {
// remove the now invalid item...
}
</code></pre></p>
<p style="font-size: 20px;">关于ios - RestKit本地删除对象,依然出现在mapping中,我们在Stack Overflow上找到一个类似的问题:
<a href="https://stackoverflow.com/questions/22682037/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/22682037/
</a>
</p>
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