Unable to upload image from phone into android app built from wordpress website

Question

I built an android app by converting my wordpress website to app using webview. I am unable to upload image from phone or attach image from the library when I am creating a new post. The attach image button is not responding when clicked but sometimes it hangs the phone, so I have to close the app. The upload function is from the wordpress site. The webview was only used to load the site. I did not hand code the upload function. Please what will I do to fix it. Thanks