UITextView get the current line

Question

Is there a way (crazy hacks welcome) to get the current line as a string of a UITextView? This would include word wrapping, etc. For example, in this case:

The method would return "stack overflow. Isn't it great? I" because that is the current line based on the cursor.

It could also return "This is a test I made for" or "think so", based on the position of the cursor. I have tried working with both the UITextView methods and those of UITextInput protocol.

EDIT:

Here is the code I have attempted to use. The reason I need to find the string is to get it's length, so this is why you'll see UI based code.

NSRange location = self.textView.selectedRange;
NSString *searchString = [self.textView.text substringWithRange:NSMakeRange(0, location)];
CGSize currentStringDimensions = [searchString sizeWithFont:self.textView.font constrainedToSize:CGSizeMake(self.textView.frame.size.width, self.textView.frame.size.height) lineBreakMode:NSLineBreakByWordWrapping];    
float numberOfRows = (currentStringDimensions.width/(self.textView.frame.size.width));
float left = (float)(numberOfRows - (int)numberOfRows) * (self.textView.frame.size.width);

This doesn't work, however. I think it might have something to with words being wrapped or the differently sized characters, but the left value is inconsistent or off after the first line.

Unhinge

Show the code you have tried and what it actually returned, how close have you got (I'd say UITextInput is the correct approach). – Ranket

Will update main question with it – Unhinge

See this - #4421767 – Quoits

Answer 1

The following code solution seem to be working. The "self" in this code refers to an instance of UITextView.

- (NSString *) getLineString:(NSRange)range
{
    NSLayoutManager *manager = self.layoutManager;

    // Convert it to a glyph range
    NSRange matchingGlyphRange = [manager glyphRangeForCharacterRange:range actualCharacterRange:NULL];

    // line fragment rect at location range
    CGRect rect = [manager lineFragmentRectForGlyphAtIndex:matchingGlyphRange.location effectiveRange:nil];

    // obtain the line range for the line fragment rect
    NSRange lineRange = [manager glyphRangeForBoundingRect:rect inTextContainer:self.textContainer];

    // extract the string out from lineRange
    return [self.text substringWithRange:lineRange];
}

// ... later
NSLog(@"line %@", [self getLineString:self.selectedRange]);

Paranoid

Answer 2

This worked for me (self = the UITextView)

func getLineString() -> String {
    return (self.text! as NSString).substringWithRange((self.text! as NSString).lineRangeForRange(self.selectedRange))
}

Judd

Answer 3

Swift 5 extension version of Gil's answer:

extension UITextView {
    func getLineString() -> String {
        guard let text = text else { return "" }
        return (text as NSString).substring(with: (text as NSString).lineRange(for: self.selectedRange))
    }
}

Franciscofranciska

Answer 4

I ended up using the caretRect method of UITextInput to get the offset from the left. Worked flawlessly.

Unhinge

@jonathanpeppers Unfortunately, I can't. This was for a paid internship I was doing the previous summer, so the code is inaccessible. – Unhinge

Can you re-implement the example on your own and post it? Seems like this is the point of StackOverflow, it shouldn't be the accepted answer unless it actually contains the answer. – Ayres

It was such a long time ago that I really can't recall. I'll unaccept this answer though, my apologies. – Unhinge