NSRang和UITextRang相互转换

1.根据NSRange 转换成 NSTextRange

UITextPosition *beginning = textView.beginningOfDocument;

UITextPosition *start = [textView positionFromPosition:beginning offset:range.location];

UITextPosition *end = [textView positionFromPosition:start offset:range.length];

UITextRange *textRange = [textView textRangeFromPosition:start toPosition:end]];

2.根据NSTextRange 转换成 NSRange

UITextPosition* beginning = textField.beginningOfDocument;

UITextRange* selectedRange = textField.selectedTextRange;

UITextPosition* selectionStart = selectedRange.start;

UITextPosition* selectionEnd = selectedRange.end;

const NSInteger location = [textField offsetFromPosition:beginning toPosition:selectionStart];

const NSInteger length = [textField offsetFromPosition:selectionStart toPosition:selectionEnd];