在关闭视图之前从 UITextField 读取最新值时出现问题
我有一个视图，我正在以模式方式显示以从用户那里获取登录信息。我有以下设置：
- 视图控制器是一个
UITableViewController - 该表具有三个单元格：用户名和密码字段（两者都是
UITableViewCell内的UITextField类型）和一个简单的单元格作为登录按钮。 - 从
textFieldDidEndEditing:message 中的UITextField读取值 - 。文本字段由不同的标签值标识。
问题
我的问题是，当焦点位于 UITextField 中并且用户触摸登录按钮时，相应 UITextField 的 textFieldDidEndEditing ：消息在didSelectRowAtIndexPath:之后发送。现在的问题是，我正在向 didSelectRowAtIndexPath: 中的 LoginViewControllerDelegate 发送一条新用户凭据的消息，而此时文本字段的值尚未读取。
一些想法
我有一些如何解决这个问题的想法，但每个想法都很复杂。
首先，我可以关闭登录视图，并在关闭期间通知委托人，但我想给予委托人（拥有此登录视图的人）完全控制权，我认为成功关闭登录视图应该是委托人的工作登录（登录视图仅读取凭据，委托验证这些凭据）。
其次，我还可以在呼叫代表之前读取用户名或密码，但随后我必须查找文本字段。如果视图不可见，我认为假设细胞确实存在是错误的。这只是一个很大的假设，但我不想让它变得正确。保留 UITextField 可以吗？但是，这样我就无法使用一些本身提供文本字段的自定义单元格。
基本上我想要以下内容：
- 检测到需要（有效）用户凭据，弹出登录视图
- 用户输入用户名和密码并调用完成。
- 委托人验证这些凭证。如果它们不起作用，则会显示一条消息，然后重试步骤 2。
- 凭据正常，因此关闭登录视图并继续。
I have a view that I'm displaying modally to get login information from a user. I have the following setup:
- The view controller is a
UITableViewController - The table has three cells: username and password fields (both of type
UITextFieldwithinUITableViewCell) and one simple cell as the login button. - Values are read from
UITextFieldintextFieldDidEndEditing:message - The text fields are identified by different tag values.
The problem
My problem is that when the focus is in a UITextField and user touches the login button, the respective UITextField's textFieldDidEndEditing:message is sent after the didSelectRowAtIndexPath:. Now the issue here is that I'm sending a message of new user credentials to my LoginViewControllerDelegate in the didSelectRowAtIndexPath: and at that time the text field's value is not read yet.
Some Ideas
I have some ideas how to fix this, but I have complications with each of them.
First, I could close the login view and the delegate is notified during the closing, but I want to give the delegate (one who owns this login view) full control and I think it should be the delegate's job to close the login view on successful login (the login view only reads the credentials, the delegate validates these).
Second, I could also read the username or password just before calling the delegate but then I'd have to look up the text fields. If the views are not visible, I think it is wrong to assume that the cells do exist. This is just a big if, but I wan't to make it right. Would it be ok to retain the UITextFields? This way, however, I can't use some custom cell that would itself provide the textfield.
Basically I want the following:
- Need for (valid) user credentials is detected, login view is popped up
- User inputs the username and password and invokes done.
- The delegate validates these credentials. If they do not work, a message is shown and try step 2 again.
- Credentials are ok, so close the login view and continue.
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经过所有技巧之后，我终于想到，只需在调用委托之前辞职第一响应者就可以解决此问题。在表视图控制器中，我只需添加一个调用：
findFirstResonder来自一个类别，可以在 此处。After all tricks I finally figured that simply resigning the first responder right before invoking the delegate fixed this. In the table view controller I simply had to add a call:
The
findFirstResonderis from a category and can be found here.尝试此操作，而不是使用第三个单元格作为登录按钮。在登录视图上使用简单的按钮。在该按钮的 IBAction 上，您可以验证用户输入。
Try this instead of using third cell as login button. Use a simple button on login view. On that button's IBAction you can validate user input.
您可以使用带有两个文本字段和一个 UIButton 的简单视图。按下按钮后，您可以通过
[yourView removeFromSuperview]从超级视图中删除视图。您可以从 yourTextfield.text 接收数据。我想这一定能解决问题
You can use a simple view with two textfields and one UIButton. After the button is pressed you can just remove the view from superview by
[yourView removeFromSuperview]. You can receive the data from the yourTextfield.text.I guess this must do the trick