'move cell up'在表视图中未正确更新

Question

我在编辑模式下重新排列tableView中的单元格时遇到问题。向下移动单元格效果不错，但向上移动单元格会破坏秩序。有时它会回到正常位置，有时它会选择一个随机的位置结束。具有讽刺意味的是，Core数据模型和顺序每次都会正确结束。

我已经搜索了STO，但真的没有找到解决方案。

-没有应用手势控制，我也尝试过禁用它们。

-已尝试[self-setSuspendAutomaticTrackingOfChangesInManagedObjectContext:NO]；

-已尝试[self.tableView.canCancelContentTouches=NO]；

-NSFetchControls/delegates绕过BOOL

我用来移动单元格的代码基本上与相同

- (void)setEditing:(BOOL)editing animated:(BOOL)animated {
[super setEditing:editing animated:animated];
[_tableView setEditing:editing animated:animated];
if(editing) {
    NSInteger rowsInSection = [self tableView:_tableView numberOfRowsInSection:0];
   // Update the position of all items
   for (NSInteger i=0; i<rowsInSection; i++) {
      NSIndexPath *curIndexPath = [NSIndexPath indexPathForRow:i inSection:0];
      SomeManagedObject *curObj = [_fetchedResultsController objectAtIndexPath:curIndexPath];
      NSNumber *newPosition = [NSNumber numberWithInteger:i];
      if (![curObj.displayOrder isEqualToNumber:newPosition]) {
         curObj.displayOrder = newPosition;
      }
   }
}
}
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath {
    NSInteger moveDirection = 1;
    NSIndexPath *lowerIndexPath = toIndexPath;
    NSIndexPath *higherIndexPath = fromIndexPath;
    if (fromIndexPath.row < toIndexPath.row) {
    // Move items one position upwards
    moveDirection = -1;
    lowerIndexPath = fromIndexPath;
    higherIndexPath = toIndexPath;
}
// Move all items between fromIndexPath and toIndexPath upwards or downwards by one position
for (NSInteger i=lowerIndexPath.row; i<=higherIndexPath.row; i++) {
    NSIndexPath *curIndexPath = [NSIndexPath indexPathForRow:i inSection:fromIndexPath.section];
    SomeManagedObject *curObj = [_fetchedResultsController objectAtIndexPath:curIndexPath];
    NSNumber *newPosition = [NSNumber numberWithInteger:i+moveDirection];
    curObj.displayOrder = newPosition;
}
SomeManagedObject *movedObj = [_fetchedResultsController objectAtIndexPath:fromIndexPath];
movedObj.displayOrder = [NSNumber numberWithInteger:toIndexPath.row];
NSError *error;
if (![_fetchedResultsController.managedObjectContext save:&error]) {
    NSLog(@"Could not save context: %@", error);
} else {
   [self.tableview reloadData];
}
}

希望有人能回答这个问题，因为回答STO问题的人太棒了！：）提前感谢！！！

-更新-

我发现，当我向上移动单元格时，该方法会不断引用同一个对象并将其更新为新的顺序，而不是用新的顺序更新下一个对象。

即。向上移动单元格-结果=（Object1.order=1，Object1.order=2，Object1.order=3）

即。向下移动单元格-结果=（Object1.order=1，Object2.order=2，Object3.order=0）

Answer 1

更改

for (NSInteger i=lowerIndexPath.row; i<=higherIndexPath.row; i++)

至

for (NSInteger i=fromIndexPath.row; i<=toIndexPath.row; i -= moveDirection)

Answer 2

在尝试了很多事情之后，我又回到了apple-docs的方法。对于其他和我有同样问题的人，请创建一个从coreData中获得的NSArray的可变副本，并使用apple-docs从索引中插入和删除。它似乎为我解决了问题

http://developer.apple.com/library/ios/#documentation/uikit/reference/UITableView_Class/Reference/Reference.html