Convert selectedTextRange UITextRange to NSRange

问题

How can I convert a UITextRange object to an NSRange? I've seen plenty of SO posts about going the other direction but that's the opposite of what I need. I'm using the UITextRange selectedTextRange which is a property of a UITextView. It returns a UITextRange but I need a range.

回答1:

You need something like this:

- (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);
}

回答2:

Here's a Swift extension based on the answer by Vitaly S.

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)
    }
}

Swift 4

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)
    }
}

回答3:

UITextView has a property

@property(nonatomic) NSRange selectedRange;

来源：https://stackoverflow.com/questions/21149767/convert-selectedtextrange-uitextrange-to-nsrange

标签

ios

objective-c

nsrange

uitextrange