ios - UIKeyInput 的提前输入问题

Question

我有一个控制器，它接受自定义键输入并以独特的方式显示它。它成为关键响应者并实现UIKeyInput。

https://developer.apple.com/reference/uikit/uikeyinput

它是在 8.0 中实现的，在 iOS 键盘上的预输入功能之前。我正在为 10.0 更新它，但它不能很好地管理交互。

- (void)deleteBackward {
  NSString *text = self.codedLabel.text;

  if (text.length > 0) {
    text = [text substringToIndex:text.length-1];
  }

  self.codedLabel.text = text;
  self.decodeLabel.text = [text stringByReplacingOccurrencesOfString:@"\n" withString:@" | "];
  [self saveText:text];
}

- (BOOL)hasText {
  NSString *text = self.codedLabel.text;
  return (text.length > 0);
}

- (void)insertText:(NSString *)newtext {
  NSString *text = self.codedLabel.text;

  text = [text stringByAppendingString:newtext];
  self.codedLabel.text = text;
  self.decodeLabel.text = [text stringByReplacingOccurrencesOfString:@"\n" withString:@" | "];
  [self saveText:text];
}

When one of the type ahead words is selected, insertText:is invoked, but the newtextvalue is always 0xa000000000000201and the debug output is

(lldb) po newtext


(lldb) p newtext.length
(NSUInteger) $1 = 1