问将selectedTextRange UITextRange转换为NSRange

EN

- (NSRange) selectedRangeInTextView:(UITextView*)textView
{
    UITextPosition* beginning = textView.beginningOfDocument;

    UITextRange* selectedRange = textView.selectedTextRange;
    UITextPosition* selectionStart = selectedRange.start;
    UITextPosition* selectionEnd = selectedRange.end;

    const NSInteger location = [textView offsetFromPosition:beginning toPosition:selectionStart];
    const NSInteger length = [textView offsetFromPosition:selectionStart toPosition:selectionEnd];

    return NSMakeRange(location, length);
}

extension UITextInput {
    var selectedRange: NSRange? {
        guard let range = self.selectedTextRange else { return nil }
        let location = offsetFromPosition(beginningOfDocument, toPosition: range.start)
        let length = offsetFromPosition(range.start, toPosition: range.end)
        return NSRange(location: location, length: length)
    }
}

extension UITextInput {
    var selectedRange: NSRange? {
        guard let range = selectedTextRange else { return nil }
        let location = offset(from: beginningOfDocument, to: range.start)
        let length = offset(from: range.start, to: range.end)
        return NSRange(location: location, length: length)
    }
}

@property(nonatomic) NSRange selectedRange;