我遵循如何将PlayN与Maven一起使用的指南，但是当我执行命令时：
maven install
失败了。
错误日志如下：
[INFO]
[INFO] --- maven-android-plugin:3.0.0-alpha-2:dex (default-dex) @ playn-showcase-android ---
[INFO] /usr/lib/jvm/java-6-openjdk/jre/bin/java [-Xmx1024m, -jar, /opt/android-sdk/platform-tools/lib/dx.jar, --dex, --output=/home/hox/Projects/playn/playn/sample/showcase/android/target/classes.dex, /home/hox/Projects/playn/playn/sample/showcase/android/target/android-classes]
[INFO]
[INFO] --- maven-jar-plugin:2.3.2:jar (default-jar) @ playn-showcase-android ---
[INFO] Building jar: /home/hox/Projects/playn/playn/sample/showcase/android/target/playn-showcase-android-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-android-plugin:3.0.0-alpha-2:apk (default-apk) @ playn-showcase-android ---
[INFO] /opt/android-sdk/platform-tools/aapt [package, -f, -M, /home/hox/Projects/playn/playn/sample/showcase/android/AndroidManifest.xml, -S, /home/hox/Projects/playn/playn/sample/showcase/android/res, --auto-add-overlay, -I, /opt/android-sdk/platforms/android-11/android.jar, -F, /home/hox/Projects/playn/playn/sample/showcase/android/target/playn-showcase-android-1.0-SNAPSHOT.ap_]
[ERROR] Cannot create the APKBuilder object
java.lang.NullPointerException
at com.jayway.maven.plugins.android.phase09package.ApkBuilder.(ApkBuilder.java:195)
at com.jayway.maven.plugins.android.phase09package.ApkMojo.doAPKWithAPKBuilder(ApkMojo.java:334)
at com.jayway.maven.plugins.android.phase09package.ApkMojo.createApkFile(ApkMojo.java:249)
at com.jayway.maven.plugins.android.phase09package.ApkMojo.execute(ApkMojo.java:207)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:319)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] PlayN Project ..................................... SUCCESS [0.125s]
[INFO] PlayN Project Archetype ........................... SUCCESS [0.650s]
[INFO] PlayN Core ........................................ SUCCESS [1.962s]
[INFO] PlayN JBox2D ...................................... SUCCESS [2.125s]
[INFO] PlayN WebGL ....................................... SUCCESS [0.914s]
[INFO] PlayN Java ........................................ SUCCESS [1.740s]
[INFO] PlayN HTML ........................................ SUCCESS [1.419s]
[INFO] PlayN Flash ....................................... SUCCESS [1.414s]
[INFO] PlayN Android ..................................... SUCCESS [1.552s]
[INFO] PlayN Server ...................................... SUCCESS [0.524s]
[INFO] PlayN Demos Project ............................... SUCCESS [0.002s]
[INFO] PlayN Hello Metaproject ........................... SUCCESS [0.003s]
[INFO] PlayN Hello Core .................................. SUCCESS [0.574s]
[INFO] PlayN Hello HTML .................................. SUCCESS [18.829s]
[INFO] PlayN Hello Flash ................................. SUCCESS [22.045s]
[INFO] PlayN Hello Android ............................... SUCCESS [14.519s]
[INFO] PlayN Showcase Metaproject ........................ SUCCESS [0.003s]
[INFO] PlayN Showcase Core ............................... SUCCESS [1.567s]
[INFO] PlayN Showcase HTML ............................... SUCCESS [21.663s]
[INFO] PlayN Showcase Flash .............................. SUCCESS [35.783s]
[INFO] PlayN Showcase Android ............................ FAILURE [11.533s]
[INFO] PlayN Cute Metaproject ............................ SKIPPED
[INFO] PlayN Cute Core ................................... SKIPPED
[INFO] PlayN Cute HTML ................................... SKIPPED
[INFO] PlayN Cute Flash .................................. SKIPPED
[INFO] PlayN Cute Android ................................ SKIPPED
[INFO] PlayN Payments .................................... SKIPPED
[INFO] PlayN Payments Core ............................... SKIPPED
[INFO] PlayN Payments Demo Metaproject ................... SKIPPED
[INFO] PlayN Payments Demo Core .......................... SKIPPED
[INFO] PlayN payments HTML ............................... SKIPPED
[INFO] PlayN payments Server ............................. SKIPPED
[INFO] PlayN Payments Demo HTML .......................... SKIPPED
[INFO] PlayN Tests Metaproject ........................... SKIPPED
[INFO] PlayN Benchmark Metaproject ....................... SKIPPED
[INFO] PlayN Benchmarks Core ............................. SKIPPED
[INFO] PlayN Benchmark HTML .............................. SKIPPED
[INFO] PlayN Manual Tests Metaproject .................... SKIPPED
[INFO] PlayN Manual Tests Core ........................... SKIPPED
[INFO] PlayN Manual Tests HTML ........................... SKIPPED
[INFO] PlayN Manual Tests Flash .......................... SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2:20.302s
[INFO] Finished at: Tue Oct 25 15:44:44 CEST 2011
[INFO] Final Memory: 122M/318M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal com.jayway.maven.plugins.android.generation2:maven-android-plugin:3.0.0-alpha-2:apk (default-apk) on project playn-showcase-android: Cannot create the APKBuilder object: NullPointerException -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
[ERROR]
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR] mvn -rf :playn-showcase-android
我发现了同样的错误here，但没有找到解决方案。
答案 0 :(得分：4)
您使用的是最近发布的Android SDK的r14吗？看起来它与Playn使用的Maven Android插件的版本有一些问题。尝试使用以下内容替换samples/showcase/android/pom.xml中的插件部分：
<plugins>
<plugin>
<groupId>com.jayway.maven.plugins.android.generation2</groupId>
<artifactId>android-maven-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<androidManifestFile>${project.basedir}/AndroidManifest.xml</androidManifestFile>
<assetsDirectory>${project.basedir}/assets</assetsDirectory>
<resourceDirectory>${project.basedir}/res</resourceDirectory>
<sdk>
<platform>11</platform>
</sdk>
<undeployBeforeDeploy>true</undeployBeforeDeploy>
<jvmArguments>
<jvmArgument>-Xmx1024m</jvmArgument>
</jvmArguments>
<dex>
<jvmArguments>
<jvmArgument>-Xmx1024m</jvmArgument>
</jvmArguments>
</dex>
</configuration>
<extensions>true</extensions>
</plugin>
</plugins>
然后cd进样品/展示并运行mvn clean然后运行mvn。
如果有效，我会在今天晚些时候升级所有样本以使用最新的android maven插件。