用核心数据实施foreach.onmove（）
我正在尝试使用核心数据实现foreach.onmove。我有两个实体，parent，与conder有一段经常的关系，并将其标记为有序。视图是这样的：
struct ParentView : View {
@ObservedObject var parent : Parent
var body : some View {
List {
ForEach($parent.children! as! [Child]) { child in
ChildView(child)
}.onMove {
parent.managedObjectContext!.performAndWait { indices, to in
(parent.children! as! NSMutableOrderedSet).moveObjects(at: indices, to: to)
try! parent.managedObjectContext!.save()
parent.objectWillChange.send()
}
}
}
}
}
结果是：
- 没有任何错误。
- 在调试
onMove函数期间，我可以看到根据需要重新订购这些项目 ManageDobjectContext.upDateDobjects在同一调试步骤中为空，然后呼叫<<<代码> save（）- 重新加载应用程序时，重新订购显然没有保存（显然是因为
更新>“更新”集合设置为＃3。
我在做什么错？如何使MOC意识到重新排序的更改？
I am trying to implement ForEach.onMove using Core Data. I have two entities, Parent with a To-Many relationship to Child, with the relationship marked as Ordered. The view is something like this:
struct ParentView : View {
@ObservedObject var parent : Parent
var body : some View {
List {
ForEach($parent.children! as! [Child]) { child in
ChildView(child)
}.onMove {
parent.managedObjectContext!.performAndWait { indices, to in
(parent.children! as! NSMutableOrderedSet).moveObjects(at: indices, to: to)
try! parent.managedObjectContext!.save()
parent.objectWillChange.send()
}
}
}
}
}
Results are:
- No errors of any kind.
- During debug of the
onMovefunction, I can see that the items are re-ordered as required - The
managedObjectContext.updatedObjectsis empty at the same debug step, before the call tosave() - When reloading the app, the re-ordering is obviously not saved (apparently because the
updatedObjectsset was empty at #3.)
What am I doing wrong? How can I make the MOC realize the re-ordering change?
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我修复了这一点，显然是用一个简单的解决方案解决的。我将其发布给子孙后代的Google搜索者。 ：d
问题与此行：
显然，拿起不变的版本并使其可变起来，但没有更新托管对象。这有效：
I fixed this, apparently with a simple solution. I am posting this for future generations of google searchers. :D
The problem is with this line:
Apparently, taking the immutable version and making it mutable works, but doesn't update the managed object. This works: