UITextView should detect links, but otherwise, should propagate touch to view below

Question

I have a text view, where I want to detect links, but when there isn't a link at the touch point, it should propagate the touch to view below (it currently doesn't). It will be contained in a table view cell, and if the user taps a link, it should interact (it works), but when another point is tapped, it should select the table view cell.

I needed text to be unselectable, so I've followed https://stackoverflow.com/a/27264999/811405 and implemented:

-(BOOL)canBecomeFirstResponder{
    return NO;
}

It wasn't sending the touch events below before that too, but I've included it just is case it interferes with a solution.

Answer 1

Instead of preventing your text view from becoming first responder, you need to subclass the hitTest method so that it returns the textView when the click occured inside a link and return nil otherwise.

@interface LinkOnlyTextView : UITextView
@end

@implementation LinkOnlyTextView

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    NSUInteger glyphIndex = [self.layoutManager glyphIndexForPoint:point inTextContainer:self.textContainer fractionOfDistanceThroughGlyph:nullptr];
    NSUInteger characterIndex = [self.layoutManager characterIndexForGlyphAtIndex:glyphIndex];
    if (characterIndex < self.textStorage.length) {
        if ([self.textStorage attribute:NSLinkAttributeName atIndex:characterIndex effectiveRange:nullptr]) {
            return self;
        }
    }
    return nil;
}

@end

There is a Swift version of this code snippet provided by @blwinters in a later answer to this question here: https://stackoverflow.com/a/47913329/1279096

Answer 2

Here is a Swift version of @Dalzhim's answer, incorporating the adjustment from @jupham to check that point is actually contained within glyphRect.

override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {

    let glyphIndex = self.layoutManager.glyphIndex(for: point, in: self.textContainer)

    //Ensure the glyphIndex actually matches the point and isn't just the closest glyph to the point
    let glyphRect = self.layoutManager.boundingRect(forGlyphRange: NSRange(location: glyphIndex, length: 1), in: self.textContainer)

    if glyphIndex < self.textStorage.length,
        glyphRect.contains(point),
        self.textStorage.attribute(NSAttributedStringKey.link, at: glyphIndex, effectiveRange: nil) != nil {

        return self
    } else {
        return nil
    }
}