< UITextinputDelegate>的问题协议实现 [英] Problems with <UITextinputDelegate> protocol implementation

问题描述

我想要实现的是一个 UITextField ，将字视为字符。具体来说，我试图看到数学表达式（例如，一个字符），我想通过实现我自己的UITextInputDelegate来解决这个问题，但是当我实现或采用这个协议时，这个协议的四个必需的函数永远不会被调用尝试通过以下方式实现：

通过子类化 UITextField 。

  @interface BIDUItextFieldDelegate：UITextField< UITextInputDelegate> 
  

通过子类化NSObject。

  @interface BIDTextfieldInputDelegate：NSObject< UITextInputDelegate> 
  

相应的.m文件包含：

  @implementation BIDTextfieldInputDelegate 
 
 
  - （void）selectionWillChange：（id< UITextInput>）textInput 
 {
 NSLog（@sWill）; 
} 
 
  - （void）selectionDidChange：（id< UITextInput>）textInput 
 { 
 NSLog（@sDid）; 
} 
 
  - （void）textWillChange：（id< UITextInput>）textInput 
 {
 NSLog（@tWill）; 
} 
 
  - （void）textDidChange：（id< UITextInput>）textInput 
 {
 NSLog（@tDid）; 
} 
  

例如，对于第二种方法（通过子类化NSObject），我执行以下操作在应用程序中显示的附加自定义UITextfield类中的（id）init方法中：

  // textInputDel是一个实例的定制NSObject类采用上述UITextInputDelegate协议
 self.textInputDel = [[BIDTextfieldInputDelegate alloc] init]; 
 
 self.inputDelegate = self.textFieldDel;有没有人知道我做错了什么，还是有更好的解决方案？
解决方案
  UITextInputDelegate 不是 相反，系统创建符合 UITextInputDelegate 的对象，并将其分配为符合第一个响应者的 .inputDelegate 到 UITextInput 。
 
 
 
  UITextInputDelegate 的方法是方法为了使您的UITextInput符合回复者在您的 .inputDelegate 上调用通知您已通过除键盘输入之外的方式更改了您的文本或选择。 
 
What I am trying to implement is a UITextField that sees words as characters. Specifically, im trying to see the mathemathical expression sin( as one character for example. I thought to solve this problem by implementing my own UITextInputDelegate. However, the four required functions from this protocol never get called when I implement or adopt this protocol. I tried implementing it in the following ways:

By subclassing a UITextField.
@interface BIDUItextFieldDelegate : UITextField < UITextInputDelegate >
By subclassing a NSObject.
@interface BIDTextfieldInputDelegate : NSObject < UITextInputDelegate >
The corresponding .m file contains:
@implementation BIDTextfieldInputDelegate


- (void)selectionWillChange:(id <UITextInput>)textInput
{
    NSLog(@"sWill");
}

- (void)selectionDidChange:(id <UITextInput>)textInput
{
    NSLog(@"sDid");
}

- (void)textWillChange:(id <UITextInput>)textInput
{
    NSLog(@"tWill");
}

- (void)textDidChange:(id <UITextInput>)textInput
{
    NSLog(@"tDid");
}
For example for the second approach (via subclassing NSObject), I do the following in the (id) init method in an additional custom UITextfield class which is displayed within the app:
//textInputDel is an instance of the custom NSObject class that adopts the above UITextInputDelegate protocol
self.textInputDel = [[BIDTextfieldInputDelegate alloc] init];

self.inputDelegate = self.textFieldDel;
Does anyone know what I am doing wrong, or has a better solution?
解决方案
UITextInputDelegate is not a protocol that you implement; rather, the system creates an object conforming to UITextInputDelegate, and assigns it as the .inputDelegate of a First Responder that conforms to UITextInput.

The methods of UITextInputDelegate are methods for your UITextInput-conforming responder to call on your .inputDelegate to inform it that you have changed your text or selection via means other than keyboard input.

                        
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