使用NSNotifications从TableViewController导航回UIViewController [英] Navigating back to UIViewController from TableViewController using NSNotifications

问题描述

我有一个例外：

Thread 1: EXC_Breakpoint (code = EXC_I386_BPT,subcode=0x0)

在我的故事板中，我有3个控制器。导航控制器，UIViewController，然后一个tableviewcontroller。当应用程序首次启动UIViewController时显示。我添加一些东西到核心数据数据库。然后在这个控制器本身我有一个检查记录栏按钮。我点击它，并移动到第三个控制器的tableviewcontroller。在这里我可以看到当天添加的记录。我点击了我刚刚添加的那个，并使用NSNotifications遍历到UIviewcontroller屏幕，如下所示：

In my story board i have 3 controllers. Navigation controller, UIViewController and then a tableviewcontroller. When the app first launches UIViewController is shown. I add some stuff to the Core Data DB. Then on this controller itself i have a "Check Records" bar button. I click that and move to the 3rd controller the tableviewcontroller. Here i can see the records that i added on that day. I click the one i just added and traverse back to the UIviewcontroller screen using NSNotifications like this:

//This code is in tableviewcontroller.didSelectRowAtIndexPath

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
ITMAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    appDelegate.salesOrderObject = [self.salesOrdersArray objectAtIndex:indexPath.row];

    NSNotification *notification =[NSNotification notificationWithName:@"reloadRequest"
                                                                object:self];
    [[NSNotificationCenter defaultCenter] postNotification : notification];

    [self.navigationController popViewControllerAnimated:YES];
}

在我的ViewController viewDidLoad中，我写这个代码来收听通知。 p>

In my ViewController viewDidLoad i write this code to listen to the notification.

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


-(void)newReloadData
{
self.salesOrder =  self.appDelegate.salesOrderObject; //self.reloadedSOObject; //appDelegate.salesOrderObject;

if(self.salesOrder !=nil)
{
//I add UItextviews,textfields,buttons etc here to a scrollview.
ITMCustomView *cView = [[ITMCustomView alloc] initWithFrame:CGRectMake(187, 660, 400, 400)
                                                     andOrderedItem:@"New"
                                                             andTag:self.tagNumber
                                                      withFoldArray:self.foldTypeArray
                                                      withRollArray:self.rollTypeArray];

        cView.tag =self.tagNumber;
        NSLog(@"Assigned tag is %d",cView.tag);

        cView.delegate = self;

        //[self.scrollView addSubview:customView];

        //self.scrollView.contentSize = CGRectMake(187, 660, 400, 400).size;


        CGPoint scrollPoint = CGPointMake(0.0, (cView.frame.origin.y/500)*400);
        [self.scrollView setContentOffset:scrollPoint animated:YES];

        [self.scrollView addSubview:cView];

        CGFloat scrollViewHeight = 0.0f;
        for (UIView *view in self.scrollView.subviews)
        {
            scrollViewHeight += view.frame.size.height;
        }

        CGSize newSize = CGSizeMake(320,scrollViewHeight);
        //CGRect newFrame = (CGRect){CGPointZero,newSize};
        [self.scrollView setContentSize:newSize];
        NSLog(@"750 the tag number is %d",self.tagNumber);
        NSLog(@"the scroll view height is %f",scrollViewHeight);
        self.currentCGRectLocation = cView.frame;
}
}

我在想，如果在添加一些东西时发生异常滚动视图。或者再看堆栈溢出，可能是由于委托或NSnotification。我不明白为什么和发生异常的地方。写这行代码给我这个例外？

I am thinking if the exception occurs at adding something to scroll view.Or on looking some more on stack overflow it could be either because of delegate or NSnotification. I cant figure out why and where the exception occurs.Does writing this line of code give me this exception?

[self.navigationController popViewControllerAnimated:YES];

这个问题是这个问题的扩展
将自定义视图添加到UIScrollview时，滚动时会导致卡住的屏幕

this question is extension of this question Adding Customview to UIScrollview results in stuck screen when Scrolling

我不知道它在哪里/如何得到这个异常。如果您需要更多信息，请问。谢谢...

I have no idea where/how its getting this exception. If you need more info please ask. Thanks...

推荐答案

当您调用 newReloadData 您通知通知中心哪些类具有 @reloadRequest字符串与 newReloadData 方法应该运行它，所以你需要首先弹出视图，然后调用通知

One thing might be when you call newReloadData you notify notification center that what class has@"reloadRequest" string with newReloadData method should run it, so you need to first pop the view then call the notification

只需尝试更改行顺序，首先调用 [self.navigationController popViewControllerAnimated：YES]; 然后调用 [[NSNotificationCenter defaultCenter] postNotification：notification];

Just try change the line order first call [self.navigationController popViewControllerAnimated:YES]; then call [[NSNotificationCenter defaultCenter] postNotification : notification];

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
ITMAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    appDelegate.salesOrderObject = [self.salesOrdersArray objectAtIndex:indexPath.row];

    NSNotification *notification =[NSNotification notificationWithName:@"reloadRequest"
                                                                object:self];
    //here first pop view
    [self.navigationController popViewControllerAnimated:YES];

    //then send notification before scopes end
    [[NSNotificationCenter defaultCenter] postNotification : notification];


}

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