https://qooah.com/2012/09/27/%e9%a0%90%e8%bc%89-andr%e2%80%8b%e2%80%8boid-4-1-%e9%81%8a%e6%88%b2%e5%b9%b3%e6%9d%bf%e9%9b%bb%e8%85%a6-wikipad-%e7%8f%be%e8%ba%ab/