How to package apk with external library to android mobile

I have added the external library using eclipse. Everything is fine in the emulator. However开发者_JAVA百科, when I tried to install the apk file in real android mobile, it cannot be installed. Actually, I followed this steps to add external library.

http://developer.android.com/guide/appendix/faq/commontasks.html#addexternallibrary

Hope someone can help. Thank You.

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Do you have the option set in your phone to accept installs from unofficial sources?