模式对话框后的键盘通知
我有一个 UITableViewController，其中一些行包含文本字段，其他行显示模式视图。我在 viewWillAppear 中注册了 UIKeyboardWillShowNotification 和 UIKeyboardWillHideNotification，并在 viewWillDisappear 中取消注册。
接下来我这样做： - 单击文本字段。我收到 UIKeyboardWillShowNotification，调整表格大小以容纳键盘。 - 选择显示模式视图控制器的行，我收到 UIKeyboardWillHideNotification，并调用 viewWillDisappear。 - 关闭模态视图控制器后，调用 viewWillAppear，并且我得到一个 UIKeyboardWillShowNotification。但没有显示键盘。所以我的桌子调整了大小，但没有出现键盘。
这是 SDK 中的错误吗？或者这是常见的行为而我错过了一些东西？
I have a UITableViewController with some rows containing textfields, and other rows that show a modal view. I register for the UIKeyboardWillShowNotification and UIKeyboardWillHideNotification in viewWillAppear, and unregister in viewWillDisappear.
Next I do this:
- click on a textfield. I get the UIKeyboardWillShowNotification, resize the table to have place for the keyboard.
- select a row that presents a modal view controller, I receive the UIKeyboardWillHideNotification, and viewWillDisappear is called.
- after closing the modal view controller, viewWillAppear is called, and I get a UIKeyboardWillShowNotification. But no keyboard is shown. So my table is resized, but no keyboard appears.
Is this a bug in the SDK? Or is it common behavior and I'm missing something?
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你的逻辑对我来说是正确的。但我想知道每次
viewWillAppear注册UIKeyboardWillHideNotification可能会出现问题。尝试在viewDidLoad中仅注册一次并在dealloc中取消订阅。我在想，也许当您在关闭模态视图后再次注册时，通知中心会向您发送旧通知。如果您注册一次通知，您将不会收到比发布更多的通知。Your logic seams correct to me. But I wonder about a possible problem with registering for a
UIKeyboardWillHideNotificationevery time yourviewWillAppear. Try to register only once inviewDidLoadand unsubscribe indealloc. I am thinking that maybe when you register again after you dismiss the modal view the Notification Center sends you an old notification. If you register once for a notification you will not get it more then it is posted.