iOS how to cache data when kill application? <p>I am developing a new feature for my app. I want cache all datas get from web service to read when offline. <br> Current, my app can cache data but when I killed my app It didn't work. <br> I saw an application <a href="https://itunes.apple.com/us/app/smartnews-trending-news-stories/id579581125?mt=8" rel="nofollow">https://itunes.apple.com/us/app/smartnews-trending-news-stories/id579581125?mt=8</a> can cache everything when killed application. <br>Do you have some suggest for me? <br> Thanks.</p>