nylon009 / reinjectplugin

ReInjectPlugin

ReInjectPlugin is an android build plugin. It uses ASM to modify classes without write duplicate code in many places. Inspired by xposed, the user just define original class and method, and write inject class and method, then the code will be injected to apk.

Sample

use plugin

ReInjectPlugin is already published to mavenCenter, please add mavenCenter in your mvn config update root project's build.gradle

buildscript {
    dependencies {
        classpath 'io.github.nylon009:reinject-plugin:0.0.1'
    }
}

update app/build.gradle

plugins {
    id 'io.github.nylon009.reinject-plugin'
}

Config file

add ReInject.json file in the app project path: Please note the method for static and non static method are different in InjectUtil.java, for non static method, the inject function should use the origin class as the first parameter.

{
  "injects": [
    {
      "className": "com.nylon.app.Utils",
      "methodName": "foobar",
      "methodSignature": "(Ljava/lang/String;)V",
      "injectClassName": "com.nylon.app.InjectUtils",
      "injectEnterMethodName": "foobarEnter",
      "injectExitMethodName": "foobarExit"
    },
    {
      "className": "com.nylon.app.Utils",
      "methodName": "hello",
      "methodSignature": "(Ljava/lang/String;)V",
      "injectClassName": "com.nylon.app.InjectUtils",
      "injectEnterMethodName": "helloEnter",
      "injectExitMethodName": "helloExit"
    }
  ]
}

Inject for static method

original code: com.nylon.app.Utils

public static void foobar(String test) {
    Log.d(TAG, "foobar");
}

after injected:

public static void foobar(String test) {
    InjectUtils.foobarEnter(test); // this is injected by asm
    Log.d(TAG, "foobar");
    InjectUtils.foobarExit(test);  // this is injected by asm
}

Inject for none-static method

origin

public void hello(String msg) {
    Log.d(TAG, "hello " + msg);
}

after injected

public void hello(String msg) {
    InjectUtils.helloEnter(this, msg);
    Log.d(TAG, "hello " + msg);
    InjectUtils.helloExit(this, msg);
}

How to build your own

Update the Plugin module, change to snapshot version, and publish plugin to local repo directory

 ./gradlew :Plugin:assemble :Plugin:publishAllPublicationsToMyRepoRepository

this project already add local repo directory as maven center, so no need to change it. update the app/build.gradle to use snapshot version.

Reference

• Android ASM自动埋点方案实践
• ASM homepage
• Sentry: Bytecode transformations: The Android Gradle Plugin
• AndroidPluginStudy
• 神策 Android 全埋点插件介绍