ios - 不调用 NSFetchedResultsControllerDelegate 委托(delegate)方法
<p><p>这是我的代码:</p>
<pre><code>class FetchResultControllerDataProvider: NSObject, NSFetchedResultsControllerDelegate {
private let fetchedResultController: NSFetchedResultsController
private var delegate: TodayViewController!
init(fetchedResultController: NSFetchedResultsController, delegate: TodayViewController) {
self.fetchedResultController = fetchedResultController
self.delegate = delegate
super.init()
self.fetchedResultController.delegate = self
try! self.fetchedResultController.performFetch()
}
func controllerWillChangeContent(controller: NSFetchedResultsController) {
print("Controller will change")
}
func controllerDidChangeContent(controller: NSFetchedResultsController) {
print("COntroller did changed")
}
func controller(controller: NSFetchedResultsController, didChangeSection sectionInfo: NSFetchedResultsSectionInfo, atIndex sectionIndex: Int, forChangeType type: NSFetchedResultsChangeType) {
print("Controller did change section")
}
func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {
print("Controller did change object at indexpath")
}
}
func loadData() {
let request = NSFetchRequest(entityName: Transaction.entityName)
request.predicate = Transaction.defaultPredicate
request.sortDescriptors = []
request.returnsObjectsAsFaults = false
request.fetchBatchSize = 20
let frc = NSFetchedResultsController(fetchRequest: request, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
let dataProvider = FetchResultControllerDataProvider(fetchedResultController: frc, delegate: self)
dataSource = TableViewDataSource(tableView: self.tableView, dataProvider: dataProvider, delegate: self)
}
</code></pre>
<p>当我添加数据时，不会调用 <code>FetchResultControllerDataProvider</code> 中的任何方法。但我不知道为什么。 </p>
<p>有人可以帮我吗？</p>
<p>编辑:</p>
<p>添加数据:</p>
<pre><code>func addTransaction() {
self.context.performChanges {
Transaction.insert(self.context, name: self.name.text!, amount: Double(self.amount.text!)!, type: self.currentTypeTag)
}
public func saveOrRoleback() -> Bool {
do {
try save()
return true
} catch {
rollback()
return false
}
}
public func performChanges(block: () -> ()) {
performBlockAndWait {
block()
self.saveOrRoleback()
}
}
</code></pre>
<p>所以这部分代码被调用了，并没有抛出错误。<br/>
但是我试图检查核心数据sql文件，它似乎是空的。所以没有添加数据。</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>添加数据时，您需要检查委托(delegate)和 fetchedResultsController 对象是否仍然存在并正确填充。您可以尝试打印这些变量的值吗？</p>
<pre><code>self.fetchedResultController
self.fetchedResultController.delegate
</code></pre>
<p>您的<code>PersistentStore</code> 中添加数据时是否插入了数据？</p></p>
<p style="font-size: 20px;">关于ios - 不调用 NSFetchedResultsControllerDelegate 委托(delegate)方法，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/37647629/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/37647629/
</a>
</p>
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