You must restart adb and Eclipse.

问题：

[2013-05-06 11:14:07 -HelloWorld] ------------------------------

[2013-05-06 11:14:07 -HelloWorld] Android Launch!

[2013-05-06 11:14:07 - HelloWorld]The connection to adb is down, and a severe error has occured.

[2013-05-06 11:14:07 -HelloWorld] You must restart adb and Eclipse.

[2013-05-06 11:14:07 -HelloWorld] Please ensure that adb is correctly located at 'D:\ProgramFiles\adt-bundle-windows-x86\sdk\platform-tools\adb.exe' and can be executed.

 

解决办法：计算机右键/属性/高级系统设置/环境变量/Path的值设置为 

%ANDROID_SDK_HOME%/tools;%ANDROID_SDK_HOME%platform-tools,然后重新启动eclipse！

 

其中, ANDROID_SDK_HOME为另外一个环境变量，值为：

D:\ProgramFiles\android-sdk-windows（视具体情况而定）