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我在编辑模式下重新排列 tableView 中的单元格时遇到问题。向下移动单元格可以正常工作，但向上移动单元格会对订单造成严重破坏。有时它会回到正常位置，有时它会选择一个随机点结束。具有讽刺意味的是，Core 数据模型和顺序每次都正确结束。

我搜索了STO，确实没有找到解决方案。

- 没有应用手势控制，我也尝试过禁用它们。

-尝试 [self setSuspendAutomaticTrackingOfChangesInManagedObjectContext:NO];

- 试过 [self.tableView.canCancelContentTouches = NO];

-NSFetchControls/delegates 被 BOOL 绕过

我用来移动单元格的代码与以下基本相同：

- (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 问题的人真是太棒了！：） 提前致谢！！！

-更新-

我发现当我向上移动单元格时，该方法会一直引用同一个对象并将其更新为新顺序，而不是使用新顺序更新下一个对象。

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

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

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2 回答 2

0

改变

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

至

for (NSInteger i=fromIndexPath.row; i<=toIndexPath.row; i -= moveDirection)
于 2013-07-23T03:34:22.140 回答
0

在尝试了很多事情之后，我回到了苹果文档的方式。对于与我有同样问题的其他人，请创建从 coreData 获得的 NSArray 的可变副本，并使用苹果文档从索引中插入和删除的方式。它似乎为我解决了这个问题。:)

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

于 2013-07-24T06:44:55.170 回答