Fixing ProGuard "Warning: can't write resource [META-INF/MANIFEST.MF]" Updated version of http://www.dancartoon.com/2012/01/14/fixing-proguard-warning-cant-write-resource-meta-infmanifest-mf/

custom_rules.xml

<?xml version="1.0" encoding="UTF-8"?>
<project name="custom_rules">
    <!--
    Suppress "Warning: can't write resource [META-INF/MANIFEST.MF] (Duplicate zip entry [classes.jar:META-INF/MANIFEST.MF])".
  	Per http://www.dancartoon.com/2012/01/14/fixing-proguard-warning-cant-write-resource-meta-infmanifest-mf/
  	Target "-obfuscate" copied from ${sdk.dir}/tools/ant/build.xml v21.
  	-->
    <target name="-obfuscate">
        <if condition="${proguard.enabled}">
            <then>
                <property name="obfuscate.absolute.dir" location="${out.absolute.dir}/proguard" />
                <property name="preobfuscate.jar.file" value="${obfuscate.absolute.dir}/original.jar" />
                <property name="obfuscated.jar.file" value="${obfuscate.absolute.dir}/obfuscated.jar" />
                <!-- input for dex will be proguard's output -->
                <property name="out.dex.input.absolute.dir" value="${obfuscated.jar.file}" />
  
                <!-- Add Proguard Tasks -->
                <property name="proguard.jar" location="${android.tools.dir}/proguard/lib/proguard.jar" />
                <taskdef name="proguard" classname="proguard.ant.ProGuardTask" classpath="${proguard.jar}" />
  
                <!-- Set the android classpath Path object into a single property. It'll be
                     all the jar files separated by a platform path-separator.
                     Each path must be quoted if it contains spaces.
                -->
                <pathconvert property="project.target.classpath.value" refid="project.target.class.path">
                    <firstmatchmapper>
                        <regexpmapper from='^([^ ]*)( .*)$$' to='"\1\2"'/>
                        <identitymapper/>
                    </firstmatchmapper>
                </pathconvert>
  
                <!-- Build a path object with all the jar files that must be obfuscated.
                     This include the project compiled source code and any 3rd party jar
                     files. -->
                <path id="project.all.classes.path">
                    <pathelement location="${preobfuscate.jar.file}" />
                    <path refid="project.all.jars.path" />
                </path>
                <!-- Set the project jar files Path object into a single property. It'll be
                     all the jar files separated by a platform path-separator.
                     Each path must be quoted if it contains spaces.
                -->
  			<!--
  			Old:
  			<pathconvert property="project.all.classes.value" refid="project.all.classes.path">
  			New:
  			-->
                <pathconvert property="project.all.classes.value" refid="project.all.jars.path" pathsep=" ">
                    <firstmatchmapper>
  					<!--
  					Old:
                        <regexpmapper from='^([^ ]*)( .*)$$' to='"\1\2"'/>
                        <identitymapper/>
  					New:
  					-->
  					<regexpmapper from='^([^ ]*)( .*)$$' to='-injars "\1\2"(!META-INF/MANIFEST.MF)'/>
  					<regexpmapper from='(.*)' to='-injars \1(!META-INF/MANIFEST.MF)'/>						
                    </firstmatchmapper>
                </pathconvert>
  
                <!-- Turn the path property ${proguard.config} from an A:B:C property
                     into a series of includes: -include A -include B -include C
                     suitable for processing by the ProGuard task. Note - this does
                     not include the leading '-include "' or the closing '"'; those
                     are added under the <proguard> call below.
                -->
                <path id="proguard.configpath">
                    <pathelement path="${proguard.config}"/>
                </path>
                <pathconvert pathsep='" -include "' property="proguard.configcmd" refid="proguard.configpath"/>
  			
  			<echo>proguard: $${project.all.classes.value}=${project.all.classes.value}</echo>				
  
                <mkdir   dir="${obfuscate.absolute.dir}" />
                <delete file="${preobfuscate.jar.file}"/>
                <delete file="${obfuscated.jar.file}"/>
                <jar basedir="${out.classes.absolute.dir}"
                    destfile="${preobfuscate.jar.file}" />
                <proguard>
                    -include      "${proguard.configcmd}"
                    -include      "${out.absolute.dir}/proguard.txt"
  				-injars       ${preobfuscate.jar.file}
                    ${project.all.classes.value}
                    -outjars      "${obfuscated.jar.file}"
                    -libraryjars  ${project.target.classpath.value}
                    -dump         "${obfuscate.absolute.dir}/dump.txt"
                    -printseeds   "${obfuscate.absolute.dir}/seeds.txt"
                    -printusage   "${obfuscate.absolute.dir}/usage.txt"
                    -printmapping "${obfuscate.absolute.dir}/mapping.txt"
                </proguard>
            </then>
        </if>
    </target>
</project>

Still doesn't solve the problem for me

Here's what ProGuard is trying to do:
-obfuscate: [delete] Deleting: /home/username/myproject/ActionBarSherlock/library/bin/proguard/original.jar [delete] Deleting: /home/username/myproject/ActionBarSherlock/library/bin/proguard/obfuscated.jar [jar] Building jar: /home/username/myproject/ActionBarSherlock/library/bin/proguard/original.jar [proguard] ProGuard, version 4.7 [proguard] Reading program jar [/home/username/myproject/ActionBarSherlock/library/bin/proguard/original.jar] [proguard] Reading program jar [/home/username/myproject/ActionBarSherlock/library/libs/android-support-v4.jar] [proguard] Reading library jar [/home/username/Software/Android/android-sdk-linux/platforms/android-18/android.jar] [proguard] Preparing output jar [/home/username/myproject/ActionBarSherlock/library/bin/proguard/obfuscated.jar] [proguard] Copying resources from program jar [/home/username/myproject/ActionBarSherlock/library/bin/proguard/original.jar] [proguard] Copying resources from program jar [/home/username/myproject/ActionBarSherlock/library/libs/android-support-v4.jar] [proguard] Warning: can't write resource [META-INF/MANIFEST.MF] (Duplicate zip entry [android-support-v4.jar:META-INF/MANIFEST.MF])