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.