ios - moveRowAtIndexPath : how to delete section once last row is moved to another section

我有一个包含多个部分的表格 View 。我希望能够将行从一个部分移动到另一个部分，并在没有行时删除一个部分。我正在尝试通过 moveRowAtIndexPath 执行此操作，但我拥有的代码不起作用并引发 NSRangeException 异常。

这是一个代码示例:

- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath {

    NSUInteger fromSection = [fromIndexPath section];
    NSUInteger fromRow = [fromIndexPath row];
    NSString *fromKey = [self.keys objectAtIndex:fromSection];
    NSMutableArray *fromEventSection = [self.eventsDict objectForKey:fromKey];

    NSUInteger toSection = [toIndexPath section];
    NSUInteger toRow = [toIndexPath row];
    NSString *toKey = [self.keys objectAtIndex:toSection];
    NSMutableArray *toEventSection = [self.eventsDict objectForKey:toKey];

    id object = [[fromEventSection objectAtIndex:fromRow] retain];
    [fromEventSection removeObjectAtIndex:fromRow];
    [toEventSection insertObject:object atIndex:toRow];
    [object release];
    // The above code works just fine!

    // Try to delete an empty section. Here is where trouble begins:
    if ((fromSection != toSection) && [fromEventSection count] == 0) {
        [self.keys removeObjectAtIndex:fromSection];
        [self.eventsDict removeObjectForKey:fromKey];

        [tableView deleteSections:[NSIndexSet indexSetWithIndex:fromSection] withRowAnimation:UITableViewRowAnimationFade];
    }

最佳答案

通过将删除包装在 dispatch_async 中，我有幸在 moveRowAtIndexPath 方法结束之后的块中执行 deleteSections 方法。

    dispatch_async(dispatch_get_main_queue(), ^{
        if ((fromSection != toSection) && [fromEventSection count] == 0) {
            [self.keys removeObjectAtIndex:fromSection];
            [self.eventsDict removeObjectForKey:fromKey];
            [tableView deleteSections:[NSIndexSet indexSetWithIndex:fromSection] withRowAnimation:UITableViewRowAnimationFade];
        }
    });

关于ios - moveRowAtIndexPath : how to delete section once last row is moved to another section，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/1549632/