How to convert an Eclipse Android project to use Ant for build?

Question

I have an Android project in Eclipse I would like to convert to be built with Ant instead.

How can I achieve this? I have tried exporting an Ant build file but I'm pretty sure that's not going to work (nor does it when running ant with the exported file). I do not know much about Ant either so some explanation would also help.

EDIT: now I seem to have managed to create the needed build file but I need to add the projects libs like admob.jar to be seen by ant and used to build. as I am getting the following error

        -dex:
     [echo] Converting compiled files and external libraries into C:\Users\Jason
\Documents\Programming\Android\Android SVN\trunk\GPSAlarm\BusSnooze\bin\classes.
dex...
    [apply]
    [apply] UNEXPECTED TOP-LEVEL EXCEPTION:
    [apply] com.android.dx.util.ExceptionWithContext
    [apply]     at com.android.dx.util.ExceptionWithContext.withContext(Exceptio
nWithContext.java:46)
    [apply]     at com.android.dx.dex.cf.CfTranslator.processMethods(CfTranslato
r.java:340)
    [apply]     at com.android.dx.dex.cf.CfTranslator.translate0(CfTranslator.ja
va:131)
    [apply]     at com.android.dx.dex.cf.CfTranslator.translate(CfTranslator.jav
a:85)
    [apply]     at com.android.dx.command.dexer.Main.processClass(Main.java:297)

    [apply]     at com.android.dx.command.dexer.Main.processFileBytes(Main.java:
276)
    [apply]     at com.android.dx.command.dexer.Main.access$100(Main.java:56)
    [apply]     at com.android.dx.command.dexer.Main$1.processFileBytes(Main.jav
a:228)
    [apply]     at com.android.dx.cf.direct.ClassPathOpener.processArchive(Class
PathOpener.java:245)
    [apply]     at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPath
Opener.java:130)
    [apply]     at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpe
ner.java:108)
    [apply]     at com.android.dx.command.dexer.Main.processOne(Main.java:245)
    [apply]     at com.android.dx.command.dexer.Main.processAllFiles(Main.java:1
83)
    [apply]     at com.android.dx.command.dexer.Main.run(Main.java:139)
    [apply]     at com.android.dx.command.dexer.Main.main(Main.java:120)
    [apply]     at com.android.dx.command.Main.main(Main.java:87)
    [apply] Caused by: java.lang.NullPointerException
    [apply]     at com.android.dx.cf.code.ConcreteMethod.<init>(ConcreteMethod.j
ava:84)
    [apply]     at com.android.dx.dex.cf.CfTranslator.processMethods(CfTranslato
r.java:243)
    [apply]     ... 14 more
    [apply] ...while processing <init> ()V
    [apply] ...while processing com/google/android/apps/analytics/AnalyticsRecei
ver.class
    [apply]
    [apply] 1 error; aborting

Answer 1

Running android update project -p . on the command line, in the base folder of your project will create the necessary build.xml and supporting files for an Ant build.