自定义Gradle插件Transform

参照文章：https://www.jianshu.com/p/d53399cd507b
遇到的问题：
1、META-INF写成META-INFO。应用plugin时找不到相就的pluginid
2、自定义plugIn时没有声明package包名。一直报找不到自定义的plugin
3、可以自定义引用的名称：

group = 'com.yilong.plugin'
archivesBaseName = 'gradle-lib'//自定义名称
version = '1.0.0'

一、自定义Transform时输入的理解

JarInput包含了以下几种类型：

1、主appModule下的lib包中的jar包
--jarInput--fullCopyFiles---/Users/allenzhang/TestGradle/app/libs/core-3.3.3.jar
2、用户目录下的.gradle/cache目录下的，通过implementationa或者compile引用的第三方包
--jarInput--fullCopyFiles---/Users/allenzhang/.gradle/caches/modules-2/files-2.1/com.android.support.constraint/constraint-layout-solver/1.1.3/bde0667d7414c16ed62d3cfe993cff7f9d732373/constraint-layout-solver-1.1.3.jar

3、androidStudio安装目录，gradle/目录下的gradle插件，kotlin插件以及annotation处理插件。

 --jarInput--fullCopyFiles---/Applications/Android Studio.app/Contents/gradle/m2repository/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.2.71/kotlin-stdlib-jdk7-1.2.71.jar
--jarInput--fullCopyFiles---/Applications/Android Studio.app/Contents/gradle/m2repository/org/jetbrains/kotlin/kotlin-stdlib/1.2.71/kotlin-stdlib-1.2.71.jar
                    
--jarInput--fullCopyFiles---/Applications/Android Studio.app/Contents/gradle/m2repository/org/jetbrains/kotlin/kotlin-stdlib-common/1.2.71/kotlin-stdlib-common-1.2.71.jar
--jarInput--fullCopyFiles---/Applications/Android Studio.app/Contents/gradle/m2repository/org/jetbrains/annotations/13.0/annotations-13.0.jar

DirectoryInput包含了如下内容

1、javac包下面的class文件以及本工程的R.class资源文件,android.等包下的R.class文件。
--directoryInputs---fullCopyFiles--/Users/allenzhang/TestGradle/app/build/intermediates/javac/debug/compileDebugJavaWithJavac/classes
2、tmp/kotlin-class包下的kotlinClass文件。同样是以.class结尾
--directoryInputs---fullCopyFiles---/Users/allenzhang/TestGradle/app/build/tmp/kotlin-classes/debug
拷贝方法如下所示：

static void fullCopyFiles(TransformInvocation transformInvocation) {
        transformInvocation.outputProvider.deleteAll()
        transformInvocation.inputs.each {TransformInput input ->
            /**
             *
             1、输入源 --directoryInputs---fullCopyFiles---/Users/allenzhang/TestGradle/app/build/intermediates/javac/debug/compileDebugJavaWithJavac/classes
             * --directoryInputs---fullCopyFiles---/Users/allenzhang/TestGradle/app/build/tmp/kotlin-classes/debug
             * --directoryInputs---fullCopyFiles---/Users/allenzhang/TestGradle/app/build/intermediates/javac/debug/compileDebugJavaWithJavac/classes
             2、目标目录
             -/Users/allenzhang/TestGradle/app/build/intermediates/transforms/AjxTransform/debug/39.jar
             */
            input.directoryInputs.each {DirectoryInput directoryInput ->
                //name - a unique name for the content. For a given set of scopes/types/format it must be unique.
                File excludeJar = transformInvocation.outputProvider.getContentLocation("exclude",directoryInput.contentTypes,directoryInput.scopes,Format.JAR)
                AJXUtils.mergeJar(directoryInput.file, excludeJar)
//              FileUtils.copyDirectory(directoryInput.file,excludeJar)
            }

                    /**
                     *

                 1、输入源
                     --jarInput--fullCopyFiles---/Users/allenzhang/TestGradle/app/libs/core-3.3.3.jar
                     --jarInput--fullCopyFiles---/Applications/Android Studio.app/Contents/gradle/m2repository/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.2.71/kotlin-stdlib-jdk7-1.2.71.jar
                     --jarInput--fullCopyFiles---/Applications/Android Studio.app/Contents/gradle/m2repository/org/jetbrains/kotlin/kotlin-stdlib/1.2.71/kotlin-stdlib-1.2.71.jar
                     --jarInput--fullCopyFiles---/Users/allenzhang/.gradle/caches/modules-2/files-2.1/com.android.support.constraint/constraint-layout-solver/1.1.3/bde0667d7414c16ed62d3cfe993cff7f9d732373/constraint-layout-solver-1.1.3.jar
                     --jarInput--fullCopyFiles---/Applications/Android Studio.app/Contents/gradle/m2repository/org/jetbrains/kotlin/kotlin-stdlib-common/1.2.71/kotlin-stdlib-common-1.2.71.jar
                     --jarInput--fullCopyFiles---/Applications/Android Studio.app/Contents/gradle/m2repository/org/jetbrains/annotations/13.0/annotations-13.0.jar
                     --jarInput--fullCopyFiles---/Users/allenzhang/TestGradle/runtime/build/intermediates/intermediate-jars/debug/classes.jar
                   5\目标目录
                     /Users/allenzhang/TestGradle/app/build/intermediates/transforms/AjxTransform/debug/0.jar
                    */
            input.jarInputs.each {JarInput jarInput ->
                def dest = transformInvocation.outputProvider.getContentLocation(jarInput.name,jarInput.contentTypes,jarInput.scopes,Format.JAR)
                println("--jarInput--fullCopyFiles---"+jarInput.file)
                FileUtils.copyFile(jarInput.file,dest)
            }
        }
    }

自定义Transform的输出目录

/Users/allenzhang/TestGradle/app/build/intermediates/transforms/XXXTransform/debug/
其中XXXTransform是自定义Transform的名称
该目录内只支持jar包文件，所以输出directory时需要把所有class文件合成一个jar文件。