当导航回来时,tableview中删除的行重新出现

时间:2015-01-17 18:58:55

标签: ios uitableview

让friendsviewcontroller中有uibarbuttonItem来编辑好友列表和其他uibarbuttonitem来为小组聊天室创建组。

有多个segue用于切换视图控制器。

- (void)viewDidLoad
{
[super viewDidLoad];
self.title = @"Groups";
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"New" style:UIBarButtonItemStylePlain target:self
                                                                         action:@selector(actionNew)];
self.tableView.separatorInset = UIEdgeInsetsZero;
chatrooms = [[NSMutableArray alloc] init];
}

- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
if ([PFUser currentUser] != nil)
{
    [self refreshTable];
}
else LoginUser(self);
}

#pragma mark - User actions
- (void)actionNew
 {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Create New Group" message:nil delegate:self
                                      cancelButtonTitle:@"Cancel" otherButtonTitles:@"OK", nil];
alert.alertViewStyle = UIAlertViewStylePlainTextInput;
[alert show];
 }

#pragma mark - UIAlertViewDelegate
 - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:    (NSInteger)buttonIndex=
 {
if (buttonIndex != alertView.cancelButtonIndex)
{
    UITextField *textField = [alertView textFieldAtIndex:0];
    if ([textField.text isEqualToString:@""] == NO)
    {
        PFObject *object = [PFObject objectWithClassName:PF_CHATROOMS_CLASS_NAME];
        object[PF_CHATROOMS_NAME] = textField.text;
        [object saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error)
        {
            if (error == nil)
            {
                [self refreshTable];
            }
            else [ProgressHUD showError:@"Network error."];
        }];
    }
}
 }
- (void)refreshTable
 {
[ProgressHUD show:nil];
PFQuery *query = [PFQuery queryWithClassName:PF_CHATROOMS_CLASS_NAME];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error)
{
    if (error == nil)
    {
        [chatrooms removeAllObjects];
        for (PFObject *object in objects)
        {
            [chatrooms addObject:object];
        }
        [ProgressHUD dismiss];
        [self.tableView reloadData];
    }
    else [ProgressHUD showError:@"Network error."];
}];
 }

#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [chatrooms count];
 }

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell"];
if (cell == nil) cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"cell"];

PFObject *chatroom = chatrooms[indexPath.row];
cell.textLabel.text = chatroom[PF_CHATROOMS_NAME];

return cell;
 }

 - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

if (editingStyle == UITableViewCellEditingStyleDelete) {
    PFObject *chatroom = [chatrooms objectAtIndex:indexPath.row];
    [chatrooms removeObjectAtIndex:chatroom];
    //[chatrooms removeObjectAtIndex:indexPath.row];
    [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];    
}
}
#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView deselectRowAtIndexPath:indexPath animated:YES];
PFObject *chatroom = chatrooms[indexPath.row];
NSString *roomId = chatroom.objectId;
CreateMessageItem([PFUser currentUser], roomId, chatroom[PF_CHATROOMS_NAME]);
ChatView *chatView = [[ChatView alloc] initWith:roomId];
chatView.hidesBottomBarWhenPushed = YES;
[self.navigationController pushViewController:chatView animated:YES];
 }

导航回TableView

时,表视图中的已删除行重新出现
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

if (editingStyle == UITableViewCellEditingStyleDelete) {
    PFObject *chatroom = [chatrooms objectAtIndex:indexPath.row];
    [chatrooms removeObjectAtIndex:chatroom];
    [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];   
}
}

我无法找到我丢失的代码或者我究竟做错了什么。

如果有人可以请指出。

非常感激。

感谢。

1 个答案:

答案 0 :(得分:1)

在提交删除时,您的代码会移除chatrooms中的对象,这是您案例中表格视图的数据源,但这会发生在您应用的内存中,来源 {{填充1}}不会改变。因此,在MVC中,在视图的状态发生变化后,应用程序的模型状态不会更新。

每次显示表视图时,您的代码都会填充chatrooms中的chatrooms,如果模型的状态尚未更改,则代码与之前的列表相同,因此表视图不会不要改变。

编辑:您需要考虑应用在此表格视图中执行的操作,而不是使用其他方法来刷新表格视图。如果用户可以删除表视图中的内容,那么您的应用程序是否应该更新模型(此模型可以是本地或远程数据库,属性列表文件等)?如果是,则在用户在表视图中插入或删除行时更新模型;好吧,如果没有,那么你问的问题不是问题,或者表格视图可能会关闭编辑。

EDIT1:

如果您确实需要根据代码更新数据,则可能需要执行以下操作:

refreshTable

也就是说,您可能需要实现类- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath { if (editingStyle == UITableViewCellEditingStyleDelete) { PFObject *chatroom = [chatrooms objectAtIndex:indexPath.row]; [chatrooms removeObjectAtIndex:indexPath.row]; PFQuery *query = [PFQuery queryWithClassName:PF_CHATROOMS_CLASS_NAME]; [query deleteChatroom:chatroom]; [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic]; } } 的方法deleteChatroom: