问题出现：
Path.isConvex is not supported.
Rendering problems ..
Couldn't resolve resource @dimen/...等等
资源文件均找不到。
解决办法：
Android studio : File → Invalidate caches / Restart ->Invalidate caches / Restart
参考：http://stackoverflow.com/questions/19429948/couldnt-resolve-resource-in-android-studios-preview