如何用动画从UITableView中删除行？

Question

我在从表视图中删除行时遇到问题.当按下行中的删除按钮时,我正在使用下面的代码:

NSIndexPath *indexPath = [NSIndexPath indexPathForRow:control.tag-100 inSection:0];
[resultList removeObjectAtIndex:indexPath.row];
[resultView beginUpdates];
[resultView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
[resultView endUpdates];
//[resultView reloadData];

第一行已成功删除,但随后索引不正确.因此,当我删除最后一行时,它会给出索引超出范围的异常.

细胞生成代码是:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"personalizeTableCell";

    PersonalizeCell *cell = (PersonalizeCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
        cell = [[PersonalizeCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];        
    cell.title.text = @"text";
    cell.rateView.tag = indexPath.row + 100;
    return cell;
}

我哪里错了？

更新:

    for (NSInteger j = 0; j < [venuesTableView numberOfSections]; ++j)
    {
        for (NSInteger i = 0; i < [venuesTableView numberOfRowsInSection:j]; ++i)
        {
           PersonalizeCell* cell = (PersonalizeCell*)[venuesTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:j]];
           cell.rateView.tag = 100 + i;
        }
    }

解决了我的问题.感谢Nenad M.

Answer 1

假设您[NSIndexPath indexPathForRow:control.tag-100 inSection:0];返回正确的索引路径....您是否尝试removeObjectAtIndex在begin-/end-updates"括号"内移动调用？:

NSIndexPath *indexPath = [NSIndexPath indexPathForRow:control.tag-100 inSection:0];
[resultView beginUpdates];
[resultList removeObjectAtIndex:indexPath.row];
[resultView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
[resultView endUpdates];

更新:

cell.rateView.tag删除第一个单元格后,显然你的错了.因此,在每次删除(即每次删除removeObjectAtIndex...)之后,您必须重新迭代剩余的tableview-cells,重新分配正确的标记值(cell.rateView.tag = indexPath.row + 100)!否则你[NSIndexPath indexPathForRow:control.tag-100 inSection:0];将返回一个错误的indexPath,因此导致你的越界错误!

重新分配标记值:

您不必重新加载整个表,只需遍历剩余的单元格,然后重新分配标记值[resultView endUpdates];:

NSMutableArray *cells = [[NSMutableArray alloc] init];
for (NSInteger j = 0; j < [tableView numberOfSections]; ++j)
{
    for (NSInteger i = 0; i < [tableView numberOfRowsInSection:j]; ++i)
    {
        [cells addObject:[tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:j]]];
    }
}

现在做:

for (PersonalizeCell* cell in cells)
{
    cell.rateView.tag = // new calculated tag
}

(或者直接在第一个代码片段的内部循环中进行重新分配.)

这是整个过程的一些非常典型的代码,示例中的表中有两行:

请注意,facebookRowsExpanded是您必须具有的类变量:

if ( [theCommand isEqualToString:@"fbexpander"] )
{
NSLog(@"expander button......");
[tableView deselectRowAtIndexPath:indexPath animated:NO];

NSArray *deleteIndexPaths;
NSArray *insertIndexPaths;

facebookRowsExpanded = !facebookRowsExpanded;
// you must do that BEFORE, not AFTER the animation:

if ( !facebookRowsExpanded ) // ie, it was just true, is now false
    {
    deleteIndexPaths = [NSArray arrayWithObjects:
            [NSIndexPath indexPathForRow:2 inSection:0],
            [NSIndexPath indexPathForRow:3 inSection:0],
             nil];
    [tableView beginUpdates];
    [tableView
        deleteRowsAtIndexPaths:deleteIndexPaths
        withRowAnimation: UITableViewRowAnimationMiddle];
    [tableView endUpdates];
    }
else
    {
    insertIndexPaths = [NSArray arrayWithObjects:
            [NSIndexPath indexPathForRow:2 inSection:0],
            [NSIndexPath indexPathForRow:3 inSection:0],
             nil];
    [tableView beginUpdates];
    [tableView
        insertRowsAtIndexPaths:insertIndexPaths
        withRowAnimation: UITableViewRowAnimationMiddle];
    [tableView endUpdates];
    }

// DO NOT do this at the end: [_superTableView reloadData];
return;
}

注意:您的numberOfRowsInSection代码必须使用facebookRowsExpanded

(它会像"如果facebookRowsExpanded返回7,否则返回5")

注意:您的cellForRowAtIndexPath代码必须使用facebookRowsExpanded.

(它必须返回正确的行,具体取决于您是否展开.)