"R cannot is resolved to a variable" error occurred while Eclipse (using ADT)

On 64-bit Ubuntu, Eclipse uses ADT to view the Andorid App code, and finds a lot of red (error), suggesting that R cannot find "R cannot be resolved to a variable".
We all know that R.java is generated automatically, and you can refer to the resource in the app via R.
At the same time, a closer look, under gen/my.package/did not automatically generate R.java files.

The reason for this is that the automatic generation of R.java tools requires some libraries of 32bit, which may be missing by default on 64bit systems.
The solution is also simple, just install the required libraries, for example on Ubuntu:

The code is as follows	Copy Code
jay@jay-linux:~$ sudo apt-get install ia32-libs

After you have installed the 32bit library, it is normal to refresh the project or restart Eclipse.