問題出現：
Path.isConvex is not supported.
Rendering problems ..
Couldn't resolve resource @dimen/...等等
資源文件均找不到。
解決辦法：
Android studio : File → Invalidate caches / Restart ->Invalidate caches / Restart
參考：http://stackoverflow.com/questions/19429948/couldnt-resolve-resource-in-android-studios-preview