As mentioned in your original post (https://community.pdftron.com/t/how-do-i-highlight-text-after-overriding-longmenupress-copy-clicked-and-getting-content-and-coordinates-of-the-copy-on-react-native/6789/1), you can accomplish what you want without any changes, by doing the following:
- Long-press over some text on the page to select it
- In the popup menu that appears, tap on the “Highlight” menu option (you may need to first tap the “>” button to see the “Highlight” menu option)
There should not be any programmatic changes required.