Android include .jar in ant compilation

I try to include in my application compilation a .jar compiled.

I use ant to compile my Android application.

When I 开发者_运维问答add this task to build.xml :

 <javac srcdir="${src}"
     classpath="xyz.jar" />

compilation failed on android package importation :

[javac] Compiling 1 source file
[javac] C:\HelloWorld\src\com\example\hellowolrd\HelloWorld.java:3: package android.app does not exist
[javac] import android.app.Activity;
[javac]                   ^

Whereas when my task was not in build.xml, compilation succeeded.

If you're using the standard ant script from android create project then you should be able to dump any jars in a libs directory and have them included automatically (documentation).

I just added lib to javac and it did the trick:

ant -lib lib debug

If you have a build.xml you have already edited (altered variables, custom imports, etc) and are a little nervous about running generic commands on it, you can also add:

<javac srcdir="libs"
     classpath="xyz.jar" />

to the build.xml file and it will work. It is the manual equivalent of the command

ant -lib lib debug

If you're not familiar with how Ant works, it's easier to use Eclipse for your Android projects. Then you can add jars using a GUI. http://developer.android.com/guide/appendix/faq/commontasks.html#addexternallibrary

Also, based on your other question, this appears to be what you are attempting to do: http://developer.android.com/guide/developing/projects/projects-eclipse.html#SettingUpLibraryProject