启动Flutter应用程序时出现以下错误：
??? EXCEPTION CAUGHT BY FLUTTER FRAMEWORK ??????????????????????????????????????????????????????????
The following message was thrown:
Could not navigate to initial route.
The requested route name was: "/animals/cats/lolcats"
The following routes were therefore attempted:
* /
* /animals
* /animals/cats
* /animals/cats/lolcats
This resulted in the following objects:
* MaterialPageRoute<dynamic>("/", animation: null)
* MaterialPageRoute<dynamic>("/animals", animation: null)
* null
* MaterialPageRoute<dynamic>("/animals/cats/lolcats", animation: null)
One or more of those objects was null, and therefore the initial route specified will be ignored and
"/" will be …