UITextView禁止输入表情符号的光标复位

参考链接

NSString *cleanText = [NSString removeEmojiAndOtherIllegalString:self.txtView.text];

if (![cleanText isEqualToString:self.txtView.text]) {

    UITextPosition *curPosition =       self.txtView.selectedTextRange.start;

    NSInteger offset = [[curPosition valueForKey:@"offset"] integerValue] - (self.txtView.text.length - cleanText.length);

    self.txtView.text = cleanText;

    UITextPosition *destPosition = [self.txtView positionFromPosition:self.txtView.beginningOfDocument offset:offset];

    self.txtView.selectedTextRange = [self.txtView textRangeFromPosition:destPosition toPosition:destPosition];

    //重新设置为焦点输入框

    [self.txtView becomeFirstResponder];

}