You’ve just installed Eclipse , and attempted to create your first Android Application. When clicking create, you see an error similar to this: "Error: Unable to open class file R.java "
如果出現 “Error: Unable to open class file R.java No such file or directory”。
Solution:解決方法：
The “Build Path” for your Java environment is not setup correctly in Eclipse. To fix this, follow these steps:
1) Open the Preferences Window by clicking “Window -> Preferences”
2) Find the “Java” section and expand it
3) Select “Build Path ”
4) Change the value of Source and output folder from Folders to “Project”
5) Click Apply and then “OK ”
Your problem should be resolved!
