记不住，于是原帖转过来，请看原帖：http://blog.csdn.net/ms03001620/article/details/8490238
一、生成build.xml
Eclipse中使用Ant为Android打包并且签名
SDK自带文件 在<sdk>tools/ant目录下这3个文件
其中build.xml和uibuild.xml中定义了大量基础构建方法和打包策略。我们只需要建立我们自己的build.xml并且存放在项目的根目录下，然后引用一下<sdk>tools/ant/build.xml即可。当然也可以拷贝它然后直接操作。
那么如何。以项目AntForAndroid为例。生成一个针对该项目的build.xml呢？
这里需要一个工具。就是SDK自带的android.bat .所在目录<sdk>tools/android.bat
然后通过命令行执行“android update project --path .”即可。完毕后即可通过android命令在当前项目目录下生成一个build.xml文件
新生成的3个文件 build.xml,local.properties,proguard-project.exe
二、配置ant.properties
在项目根目录新建一个ant.properties文件（不要去改变他的名字，因为<sdk>\tools\ant\build.xml会引用到这个名字）
并且在里面写入一下数据：
#keystore文件的目录，因为在根目录下所以直接写名字了
key.store=android.keystore
#这个名字就是在生成keystore时那个alias字段的值
key.alias=android
#两个密码分别写建立keystore时的两个密码
key.store.password=(your pwd)
key.alias.password=(your pwd)
三、实现自动打签名apk
右键点击项目中的build.xml->run as... 先查看下有多少种任务，当然这些任务都是来自<sdk>\tools\ant\build.xml,项目里的只是引用了它
窗口打开
默认的选择在help上。打签名包的时候执行release这个任务即可。
按照以上的步骤配置好之后就能生成签名apk。并且大家可以通过学习<sdk>\tools\ant\build.xml来理解ant的基本奥妙。
最后在项目跟目录\bin下生成apk包
Ant是非常强大的。可以实现一下功能
例如
1.在生成apk的文件名里加上日期。
2.把apk文件自动通过邮件发给其他人。
3.apk文件上传服务器
等等
第二篇：http://www.xmumu.com/post/2011-11-22/7022215
通过Android命令自动编译出build.xml文件
用途: 做自动集成编译环境.
环境搭配我就不说了(SDK/环境变量等).
进入cmd界面.
进入项目目录.
输入: android.bat list target 来查询我们现有的版本list有哪些.
记住这个ID号码,下的代码面会用到.
输入: android update project -n ButtonDemo -t 1 -p E:\workspace\android\ButtonDemo
-n 对应的是项目名称
-t 就是我们之前查询的SDK版本对应的ID,大家根据自己的项目版本做出选择即可,我这个是android-8 所以用ID 1 .
-p就是生成的路径
成功后显示:
好了以下是生成的build.xml代码段:
<?xml version="1.0" encoding="UTF-8"?>
<project name="ButtonDemo" default="help">
<!-- The local.properties file is created and updated by the ‘android‘ tool.
It contains the path to the SDK. It should *NOT* be checked into
Version Control Systems. -->
<loadproperties srcFile="local.properties" />
<!-- The ant.properties file can be created by you. It is only edited by the
‘android‘ tool to add properties to it.
This is the place to change some Ant specific build properties.
Here are some properties you may want to change/update:
source.dir
The name of the source directory. Default is ‘src‘.
out.dir
The name of the output directory. Default is ‘bin‘.
For other overridable properties, look at the beginning of the rules
files in the SDK, at tools/ant/build.xml
Properties related to the SDK location or the project target should
be updated using the ‘android‘ tool with the ‘update‘ action.
This file is an integral part of the build system for your
application and should be checked into Version Control Systems.
-->
<property file="ant.properties" />
<!-- The project.properties file is created and updated by the ‘android‘
tool, as well as ADT.
This contains project specific properties such as project target, and library
dependencies. Lower level build properties are stored in ant.properties
(or in .classpath for Eclipse projects).
This file is an integral part of the build system for your
application and should be checked into Version Control Systems. -->
<loadproperties srcFile="project.properties" />
<!-- quick check on sdk.dir -->
<fail
message="sdk.dir is missing. Make sure to generate local.properties using ‘android update project‘"
unless="sdk.dir"
/>
<!-- extension targets. Uncomment the ones where you want to do custom work
in between standard targets -->
<!--
<target name="-pre-build">
</target>
<target name="-pre-compile">
</target>
/* This is typically used for code obfuscation.
Compiled code location: ${out.classes.absolute.dir}
If this is not done in place, override ${out.dex.input.absolute.dir} */
<target name="-post-compile">
</target>
-->
<!-- Import the actual build file.
To customize existing targets, there are two options:
- Customize only one target:
- copy/paste the target into this file, *before* the
<import> task.
- customize it to your needs.
- Customize the whole content of build.xml
- copy/paste the content of the rules files (minus the top node)
into this file, replacing the <import> task.
- customize to your needs.
***********************
****** IMPORTANT ******
***********************
In all cases you must update the value of version-tag below to read ‘custom‘ instead of an integer,
in order to avoid having your file be overridden by tools such as "android update project"
-->
<!-- version-tag: 1 -->
<import file="${sdk.dir}/tools/ant/build.xml" />
</project>