performSegueWithIdentifier vs instantiateViewControllerWithIdentifier [英] performSegueWithIdentifier vs instantiateViewControllerWithIdentifier

问题描述

我似乎没有得到这个我不断得到的SIGABRT。我有这个故事板iOS应用程序，在故事板中我有一个UITableViewController。现在，我可以拿一个TVC的单元格并使其推动segue视图控制器，但是如果我需要在某些条件下停止segue动作呢？显然你不能，因为prepareForSegue：sender：方法不允许它，它似乎是转换即将执行时被调用的唯一回调。

I don't seem to get this SIGABRT I keep getting. I have this storyboard iOS application, and in the storyboard I have a UITableViewController. Now, I can take a cell of the TVC and make it push the "segue" view controller, but what if I needed to stop the "segue" action on certain conditions? Apparently you can't, since the prepareForSegue:sender: method doesn't allow for it, and it seems to be the only callback that gets called when a transition is about to get performed.

所以我猜我可以进入tableView：didSelectRowAtIndexPath：并以编程方式执行segue。不是最理想的，但仍然......

So I guessed I could go into the tableView:didSelectRowAtIndexPath: and perform the segue programmatically. Suboptimal, but still…

嗯，事实证明我错了。或者至少，我做错了什么。最明显的方法是

Well, it turns out I guessed wrong. Or at least, I'm doing something wrong. The most obvious way to do it would be

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [self performSegueWithIdentifier:@"TheOtherIdentifier" sender:self];
}

但是整个应用程序崩溃了SIGABRT，它没有提供任何有用的信息（是的，我确定是那条使应用程序崩溃的行，我检查了调试器:)此外，我正在尝试加载的VC已正确设置标识符，因为以下代码

but the whole app crashes with a SIGABRT, which does not give any useful information (and yes, I'm sure it's that line that makes the app crash, I checked with the debugger :) Moreover, the VC I'm trying to load has the identifier correctly set, because the following code

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    UIViewController *vc = [self.storyboard instantiateViewControllerWithIdentifier:@"TheOtherIdentifier"];
    [self.navigationController pushViewController:vc animated:YES];
}

有效。引号表明这显然不是应该执行此类转换的方式。

"works". Quotation marks indicate that this is clearly not the way such a transition should be performed.

现在：想法？

推荐答案

试试这个：

1. 使用第一个代码块而不是第二个代码块。


2. 在storyboard控件中，从单元格拖动到另一个视图控制器。请注意，创建了一个segue。


3. 单击segue。使用属性检查器给出segue和标识符theOtherIdentifier（建议使用小写t）。假设您正在使用导航控制器，也请选择推的segue样式。


4. 故事板将实例化其他视图控制器。请确保您的代码中没有这样做。

1. Use the first code block and not the second.
2. In storyboard control drag from the cell to the other view controller. Note that a segue is created.
3. Click on the segue. Use the attributes inspector to give the segue and identifier "theOtherIdentifier" (lower case "t" recommended). Also select a segue style of "push" assuming you are using a navigation controller.
4. Storyboard will instantiate the other view controller. Be sure you are not doing this in your code.

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