1、how to find out the Eclipse Version

From Eclipse Menu Help ----> About Eclipse

It displayed as

Eclipse Java EE IDE for Web Developers.

Version: Helios Service Release 2

Build id: 20110218-0911

eclipse has a file .eclipseproduct in its root folder which contains its version.
When you open the file it will look likes

　　name=Eclipse Platform
　　id=org.eclipse.platform
　　version=3.7.0

2、Troubleshooting ADT Installation

If you are having trouble downloading the ADT plugin after following the steps above and you are behind a firewall (such as a corporate firewall), make sure that you have properly configured your proxy settings in Eclipse. In Eclipse, you can configure proxy information from the main Eclipse menu in Window (on Mac OS X, Eclipse) > Preferences > General >Network Connections.

If you are still unable to use Eclipse to download the ADT plugin as a remote update site, you can download the ADT zip file to your local machine and manually install it:

1. Download the ADT Plugin zip file (do not unpack it):

   Package	Size	MD5 Checksum
   ADT-23.0.6.zip	103344298 bytes	f64b7e50c84799f41c642218c35f1bbe

2. Start Eclipse, then select Help > Install New Software.
3. Click Add, in the top-right corner.
4. In the Add Repository dialog, click Archive.
5. Select the downloaded ADT-23.0.6.zip file and click OK.
6. Enter "ADT Plugin" for the name and click OK.
7. In the Available Software dialog, select the checkbox next to Developer Tools and click Next.（ps:before that you need break net）
8. In the next window, you'll see a list of the tools to be downloaded. Click Next.
9. Read and accept the license agreements, then click Finish.

   If you get a security warning saying that the authenticity or validity of the software can't be established, click OK.

10. When the installation completes, restart Eclipse.

To update your plugin once you've installed using the zip file, you will have to follow these steps again instead of the default update instructions.

3、eclipse 引入 没有.project文件的Android项目的解决方法

　　用Android开发手机游戏通常会用到eclipse工具。那么如何导入现有的项目到eclipse开发环境下，并进行修改和调试呢？
　　点击File菜单，分别选择Import->General->Existing Projects into Workspace，
　　然后在Select root directory中Browse你想要加入的工程。然而我并没有成功，任我怎么点击Refresh都没有显示可用的Projects文件（你现在就可以试一试）。

　　这是为什么呢？原来这种导入方法只适用于eclipse自己创建的工程，比如说，在别人的电脑上用eclipse创建了一个工程，然后就可以用这个办法导入到你的eclipse中。
　　因为用eclipse创建的工程有一个.project文件，而有时候我们下载来的项目是没有这个文件的。
　　天无绝人之路，后来我还是找到一个更好的方法。而且这个方法更为通用，不管它以前是用什么工具创建的都可以打开。
　　选择File--New--Project，在弹出的窗口中，去掉Use default location前面的勾，
　　点击Browse，然后选择你想要打开的工程目录，还是选择你要引入的项目所在文件夹，在Poject name中输入工程的名字，接着next、finish就行了。