更新到了最新版的ADT居然没有找到ndk的目录设置，这对于ndk开发很不方便。方法也很简单。

到http://developer.android.com/sdk/installing/installing-adt.html#Troubleshooting

这里下载最新的adt更新一下就行。

一下是Google的原文

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 inWindow(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:

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

PackageSizeMD5 ChecksumADT-23.0.4.zip103336810 bytes91a43dcf686ab73dec2c08b77243492b

Start Eclipse, then selectHelp>Install New Software.

ClickAdd, in the top-right corner.

In the Add Repository dialog, clickArchive.

Select the downloaded ADT-23.0.4.zip file and clickOK.

Enter "ADT Plugin" for the name and clickOK.

In the Available Software dialog, select the checkbox next to Developer Tools and clickNext.

In the next window, you'll see a list of the tools to be downloaded. ClickNext.

Read and accept the license agreements, then clickFinish.

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

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.