Objective-C 运行时：混合方法名称？
尝试检测 UITextField 中的退格， 我尝试过子类化 UITextField 并覆盖 -[UIKeyInput deleteBackward]，但它永远不会被调用。因此，我怀疑 UITextField 将 deleteBackward 调配为另一个方法名称。
使用 Objective-C 运行时，如何确定 deleteBackward 已被 swizzled 为哪个方法名称？然后，如何更改实现，以便 UITextField 在当它为空时按下删除键。
另外，这种元编程会让我的应用程序被 App Store 拒绝吗？
In an attempt to Detect backspace in UITextField,
I've tried subclassing UITextField and overriding -[UIKeyInput deleteBackward], but it never gets called. So, I'm suspecting UITextField swizzles deleteBackward to another method name.
Using the Objective-C Runtime, how can I determine which method name deleteBackward has been swizzled to? Then, how can I change the implementation so that UITextField will call [self.delegate textField:self shouldChangeCharactersInRange:NSMakeRange(0, 0) replacementString:@""] when the delete key is pressed when it's empty.
Also, will this kind of metaprogramming get my app rejected from the App Store?
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Swizzling 不会更改方法的名称。如果是这样，则无法调用该方法，因为运行时使用该名称查找实现。它所做的只是更改调用特定方法时运行的代码的地址。
我猜测为什么
deleteBackward方法没有被调用，因为输入系统正在使用更复杂的 UITextInput 协议代替，最有可能的是replaceRange:withText:。尝试调整它并在text参数为空字符串时执行调用。还要确保您的 swizzling 函数不会返回错误。Swizzling doesn't change the name of a method. If it did, it would be impossible to call the method, since the runtime finds the implementation using the name. All it does is change the address of the code which is run when you call a specific method.
My guess as to why the
deleteBackwardmethod isn't being called is that the input system is using a method from the more complicated UITextInput protocol instead, most likelyreplaceRange:withText:. Try swizzling that and performing your call when thetextargument is an empty string. Also make sure your swizzling function doesn't return an error.