title: scraping data from website that could change
body: <p>I want to create an Android App where I can scrape data from a specific website. The informations on that website could change (textual data).Also, I don't know if the HTML structure will change over time. My questions are:</p>
  
  <ol>
  <li>Does anyone recommend a specific tool or framework for scraping
  (for free)? </li>
  <li>How can I know when informations(textual data) get changed on
  the website so that I can update my app ? </li>
  <li>How to deal with changes on the HTML structure of the website?</li>
  </ol>
  
  <p>This is my first experience in scraping and any answer could help me a lot.
  Thank you</p>