http://stackoverflow.com/questions/16731126/location-of-the-android-sdk-has-not-been-set-up-in-the-preferences-in-64-bit-win
How to Update your ADT to Latest Version?
1. In Eclipse go to Help
2. Install New Software ---> Add
3. inside Add Repository write the Name: ADT (as you want)
4. and Location: https://dl-ssl.google.com/android/eclipse/
5. after loading some time you will get Developer Tools and NDK Plugins
6. check both if you want to use NDK in the future or check Developer Tool only
click Next
7. Finish
Now My Problem Solved :-)
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Q2:android SDK manager 不見?
A2:此現象可以通過在eclipse中的-window-customize perspective-command groups availability 裏勾選Android SDK and AVD Manager出來
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Q3.no cpu/abi system image available?
A3:download Android SDK manager
restart eclipse
Q4:The project cannot be built until build path errors are resolved
A4:我簡單的在project裏選擇clean一下就解决了，不知算不算lucky。
ps.後果很嚴重，這样每個project 都要clean下才行。
之後我又在project->Properties->Android下勾選了Is Library.
看到其他人的解决方案，歸納有以下幾步：
1,看看project -- Build Automatically有沒有勾上?如果沒有,勾上以後,clean一下,重启eclipse
2,看看你的lib裏面有沒有不用的jar包,看你的.classpath文件中有沒有錯誤的路徑.
3,這是最重要的一點,有problems視圖中查看有沒有關於本項目的錯誤信息,一般都會有這样的話: The project cannot be built until build path errors are resolved 然後下面提示unbound classpath, 一般在.classpath中刪除這些path就可以了
4. 安裝Tomcat後,確保{tomcat_home}/common/lib文件夾下有jasper-runtime.jar、jsp-api.jar、servlet-api.jar、jndi.jar幾個文件。启動Eclipse,第一次启動會有一個配置過程，選擇菜單上的window/preferences，選java/classpath variables，New添加一個名为JDK_TOOLS並指向你的{jdk_home}/lib/tools.jar的環境變量。
如此以來，Eclipse運行正常了。
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Q5:actionBarActivity cannot be resolved to a type
A5:
