Question

我有一个加载表视图的navigationVC。当您点击一个单元格时，它会将一些数据复制到detailsVC，还有一个更新按钮来更新这些值。如何刷新详细信息VC中的数据而不返回到tableview并在那里更新？

这就是我想要做的事情：

的TableView＆GT;＆的DetailsView GT; EditDetails＆GT;使用更新的信息返回DetailsView

不是这个：

TableView＆gt; DetailsView＆gt; EditDetails＆gt; DetailsView（通过导航返回）＆gt; TableView＆gt;（拉到刷新）＆gt; DetailsView

修改

- (void) receiveNotifications:(NSNotification *) notification {
    if ([[notification name] isEqualToString:@"updateDetailsVC"]){
        dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
        dispatch_async(queue, ^{
            NSDictionary *userInfo = [notification userInfo];
            NSLog (@"%@", userInfo);

            PRIORITYstring = [userInfo objectForKey:@"PRIORITY"];
        });
    }
}

我能够让代码工作，并且通过NSLog，我的数据被推回为字典。

当viewDidLoad为detailsVC时，它运行一个方法，将NSString放入其对应的UILabel。

- (void)viewDidLoad {
    [super viewDidLoad];
    [self displayData];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                          selector:@selector(receiveNotifications:)
                                           name:@"updateDetailsVC"
                                           object:nil];
}



-(void)displayData {
        PRIORITYlabel.text = [NSString stringWithFormat:@"Short Description: \n%@", QDESCRIPTIONstring];
}


- (void) receiveNotifications:(NSNotification *) notification {
    if ([[notification name] isEqualToString:@"updateDetailsVC"]){
        dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
        dispatch_async(queue, ^{
            NSDictionary *userInfo = [notification userInfo];
            NSLog (@"%@", userInfo);

            PRIORITYstring = [userInfo objectForKey:@"PRIORITY"];
            //PRIORITYlabel.text = [userInfo objectForKey:@"PRIORITY"];
        });
    }
}

如何让词典覆盖初始数据呢？

Answer 1

您可以使用NSNotificationCenter。从编辑视图发布通知，并从表视图和详细信息视图中订阅相同的通知。

发布通知::

[[NSNotificationCenter defaultCenter] 
        postNotificationName:@"TestNotification" 
        object:nil userInfo: userInfo];

如果您想从编辑视图传递任何数据，您可以使用userInfo字典!!

从表格视图和详细信息视图订阅通知::

[[NSNotificationCenter defaultCenter] addObserver:self
        selector:@selector(receiveTestNotification:) 
        name:@"TestNotification"
        object:nil];

行动方法::

- (void) receiveTestNotification:(NSNotification *) notification
{
    // [notification name] should always be @"TestNotification"
    // unless you use this method for observation of other notifications
    // as well.

    if ([[notification name] isEqualToString:@"TestNotification"])
        NSLog (@"Successfully received the test notification!");
        //retrieve the userInfo dictionary received from edit view
        NSDictionary *userInfo = [notification userInfo];
}

您可以在表格视图和详细视图中添加此操作方法。

在表格视图和详细信息视图中删除观察者::

- (void) dealloc
{
    // If you don't remove yourself as an observer, the Notification Center
    // will continue to try and send notification objects to the deallocated
    // object.
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

编辑::

您可以更新displayData方法以将标签文本作为参数传递。

-(void)displayData: (NSString*) labelText{
        PRIORITYlabel.text = labelText;
}

您可以从viewDidLoad和receiveNotifications：方法调用相同的方法。

来自viewDidLoad ::

[self displayData: [NSString stringWithFormat:@"Short Description: \n%@", QDESCRIPTIONstring]];

来自receiveNotifications ::

[self displayData: [NSString stringWithFormat:@"Short Description: \n%@", [[notification userInfo] objectForKey:@"PRIORITY"]]];

如何使用从ViewController2传回的数据更新ViewController1数据

1 个答案: