文本字段响应程序不兼容 iOS4 -> iOS 5
奇怪的问题：
两个 UITextFields，由单个控制器管理，启用键盘输入。如果在字段 #1 中输入一个值并按 KB 上的“下一步”，闪烁的光标就会很好地跳转到字段 #2，一切正常。但是（仅在 iOS 5 中）如果触摸字段 #2 而不是按“下一步”，则光标会跳转到字段 #2 但不会闪烁，并且 KB 会显示死的。
单步执行代码，我发现第一种情况的顺序是：
- textFieldShouldReturn:field#1 （它为 #1 做了一个辞职的第一响应者）
- textFieldDidEndEditing:field#1 （它为 #1 做了一个辞职，并为 #1 做了一个成为） 2)
- textFieldShouldBeginEditing:field#2
在第二种情况下（当触摸字段与使用“Next”时），序列为：
- textFieldShouldBeginEditing:field#2
- textFieldDidEndEditing:field#1
- textFieldShouldBeginEditing:field#2 （再次）
- textFieldDidEndEditing:field#2 （这对 #1 和 #2 都进行了辞职）
显然，当 #2 的辞职完成后会杀死 KB，但是 为什么 iOS 5 使用字段 #2 调用 DidEndEditing？？？如何才能规避这一点呢？
更新
添加了 textFieldShouldEndEditing 的挂钩。它在 field#1 的 textFieldDidEndEditing 之前调用，但不在 field#1 的 textFieldDidEndEditing 之前调用。不过，奇怪的是，textFieldShouldBeginEditing 是在 field#2 的 textFieldDidEndEditing 之前调用的。听起来像是 iOS 代码中彻头彻尾的“欺骗错误”。
更新 2
iOS 5 不处理 testFieldDidEndEditing 之外的 resign/become 调用。规避方法见下文。
Curious problem:
Two UITextFields, managed by a single controller, enabled for keyboard input. If one enters a value in field #1 and presses "Next" on the KB, the blinking cursor jumps to field #2 just fine and everything's OK. But (only in iOS 5) if one touches field #2 instead of pressing "Next", the cursor jumps to field #2 but doesn't blink and the KB is dead.
Stepping through the code, I find that in the first case the sequence is:
- textFieldShouldReturn:field#1 (which does a resign first responder for #1)
- textFieldDidEndEditing:field#1 (which does a resign for #1 and a become for #2)
- textFieldShouldBeginEditing:field#2
In the second case (when the field is touched vs using "Next") the sequence is:
- textFieldShouldBeginEditing:field#2
- textFieldDidEndEditing:field#1
- textFieldShouldBeginEditing:field#2 (again)
- textFieldDidEndEditing:field#2 (which does a resign for BOTH #1 and #2)
Obviously, when the resign for #2 is done that kills the KB, but WHY is iOS 5 making the call to DidEndEditing with field #2??? And how could one circumvent this?
Update
Added a hook for textFieldShouldEndEditing. It's called before textFieldDidEndEditing for field#1, but not before textFieldDidEndEditing for field#1. Though, curiously, textFieldShouldBeginEditing is called just before textFieldDidEndEditing for field#2. Smells like an out-and-out "dupe error" in the iOS code.
Update 2
iOS 5 does not handle resign/become calls out of testFieldDidEndEditing. See below for circumvention.
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我得出的结论是，iOS 5 没有（正确）处理在
textFieldDidEndEditing内进行resignFirstResponder/becomeFirstResponder调用的情况。将逻辑（或多或少）移至textFieldShouldReturn（触摸会自行处理），现在似乎工作正常。I came to the conclusion that iOS 5 does not (correctly) handle the case of having
resignFirstResponder/becomeFirstRespondercalls insidetextFieldDidEndEditing. Moved the logic (more or less) totextFieldShouldReturn(touch kind of takes care of itself), and now it seems to work OK.