Error in shinyAppDir(x) : No Shiny application exists at the path "~/app"处理方法

调试shiny程序时，按照例程给出的代码

其启动代码

> library(shiny)
> runApp("~/app")

 会报错Error in shinyAppDir(x) : No Shiny application exists at the path "~/app"“”

可写作

runApp(appDir = "./app")

问题得到解决