maven构建android项目：指定aidl文件的位置

Question

我的android项目只有aidl文件，项目结构如下：

MyProject/
  src/
     main/
         com.my.aidl/
               IMyService.aidl
  pom.xml

我正在使用 maven 构建我的 android 项目。我的 pom 使用 dexguard-maven-plugin，它是 android-maven-plugin 的扩展。

在插件配置中，我明确指定了源aidl文件的目录和生成的java文件的目录。

<build>
    <plugins>
        <plugin>
           <groupId>com.saikoa.dexguard.maven</groupId>
           <artifactId>dexguard-maven-plugin</artifactId>
           <configuration>
               <aidlSourceDirectory>
                   ${project.basedir}/src/main/com/my/aidl
               </aidlSourceDirectory>

               <genDirectoryAidl>
                    ${project.build.directory}/generated-sources/aidl/main/com/my/aidl
               </genDirectoryAidl>
            </configuration>
            <extensions>true</extensions>
         </plugin>
     </plugins>
</build>

但是在我运行mvn clean install -e 之后，我得到了以下错误跟踪：

[ERROR] Failed to execute goal com.saikoa.dexguard.maven:dexguard-maven-plugin:6.1.18:generate-sources (default-generate-sources) on project MyProject: Execution default-generate-sources of goal com.saikoa.dexguard.maven:dexguard-maven-plugin:6.1.18:generate-sources failed. NullPointerException -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal com.saikoa.dexguard.maven:dexguard-maven-plugin:6.1.18:generate-sources (default-generate-sources) on project MyProject: Execution default-generate-sources of goal com.saikoa.dexguard.maven:dexguard-maven-plugin:6.1.18:generate-sources failed.
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:224)
    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:317)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:152)
    at org.apache.maven.cli.MavenCli.execute(MavenCli.java:555)
    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:214)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:158)
    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:606)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.PluginExecutionException: Execution default-generate-sources of goal com.saikoa.dexguard.maven:dexguard-maven-plugin:6.1.18:generate-sources failed.
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:115)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
    ... 19 more
Caused by: java.lang.NullPointerException
    at java.io.File.<init>(File.java:334)
    at com.jayway.maven.plugins.android.phase01generatesources.GenerateSourcesMojo.generateAidlFiles(GenerateSourcesMojo.java:1266)
    at com.jayway.maven.plugins.android.phase01generatesources.GenerateSourcesMojo.execute(GenerateSourcesMojo.java:343)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:106)
    ... 20 more
[ERROR] 
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 

怎么了？

Answer 1

几个月前有一个类似的问题，我将与电话相关的aidl 文件放置到不正确的位置（我从 Eclipse ANT 迁移到 Studio Gradle）。下面的链接对我的情况有所帮助：
how can I add the aidl file to Android studio (from the in-app billing example)以及与此相关的官方文档：
http://tools.android.com/tech-docs/new-build-system/user-guide#TOC-Project-Structure

Answer 2

取决于您的日志消息，有一个空异常。估计目录不对。您是否尝试将 genDirectoryAidl 从“generated-sources/aidl/main/com/my/aidl”更改为“generated-sources/aidl/”？也许如果你创建一个名为 'main/com/my/aidl' 的目录，你会成功。

希望这条消息可以帮助到你。

Answer 3

我可以看到 NullPointerException 可能是由一些未解决的依赖关系引起的。 Here 是类似问题的链接。 还可以尝试使用 -X 重新运行 maven 并向我们显示调试输出。