UIDocumentPickerViewController 关闭父视图控制器 [英] UIDocumentPickerViewController dismisses parent view controller

问题描述

我在视图控制器中有一个 WKWebView.当用户点击上传文件"按钮(在显示的网页上)时，UIDocumentPickerViewController 会弹出.这是意料之中且完全必要的，但是:

I have a WKWebView in a view controller. When an user clicks on "Upload File" button (which is on the webpage shown), UIDocumentPickerViewController pops up. This is expected and totally neccessary but:

每当用户单击任何按钮(上传照片或视频"、取消")时，UIDocumentPickerViewController 都会关闭自身及其所在的父视图控制器.

Whenever the user clicks on any button ("Upload Photo or Video", "Cancel"), the UIDocumentPickerViewController dismisses itself AND the parent view controller that it's in.

我为 [UIViewController deniedViewControllerAnimated:completion:] 添加了一个符号断点，并且确实看到 -dismissViewController... 被调用了两次.在第一次关闭 UIDocumentPickerViewController 之后，在第二次之后 - 我的父视图控制器.

I have added a symbolic breakpoint for [UIViewController dismissViewControllerAnimated:completion:] and indeed saw that -dismissViewController... is called twice. After the first time it dismisses UIDocumentPickerViewController, after the second one – my parent view controller.

顺便说一句，在 iPad 上没有问题，可能是因为 UIDocumentPickerViewController 以弹出框的形式呈现.

By the way, on the iPad there is no problem, probably because UIDocumentPickerViewController is presented as a popover.

为什么会发生这种情况，我该怎么办?

Why is this happening and what should I do?

谢谢！

推荐答案

我遇到了同样的问题，终于找到了解决方法.

I faced the same problem and finally managed to find a workaround.

在我的视图控制器中，如果没有点击保存按钮，我会覆盖 dismiss 方法以删除托管对象，并且与 UIImagePickerController 完美配合.

In my view controller I override dismiss method to delete managed object if save button wasn't hit and that worked perfectly with UIImagePickerController.

由于我的应用程序使用 UIDocumentPickerViewController，每次调用 documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentAt url: URL) 时，我的托管对象都会被删除，因为这会导致presentingViewController.dismiss.

As of my application uses UIDocumentPickerViewController, my managed object was deleted each time the documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentAt url: URL) was called because this causes a presentingViewController.dismiss.

所以我的解决方案是从 presentingViewController 检查 presentedViewController 是否为 nil 或者不知道是否 dismiss 方法是否被 UIDocumentPickerViewController 调用.

So my solution is to check from the presentingViewController if the presentedViewController is nilor not to know if dismiss method was called by UIDocumentPickerViewController or not.

这里是我的视图控制器中重写的 dismiss 方法.

So here is my overriden dismiss method from my view controller.

override func dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
    if self.presentedViewController == nil {
        // dismissed by the user
        myDocument.delete()
    } else {
        // dismissed by the UIDocumentPickerViewController
        // do nothing
    }
    super.dismiss(animated: flag, completion: completion)
}

希望对你有帮助.

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