Source link: https://github.com/meituan/RoboAspectJ

RoboAspectJ

RoboAspectJ is a Gradle plugin to introduce AspectJ ( Aspect- Orient Programming) to Android project. It compiles aspects(if needed) and weave them all together in FULL-PROJECT scope. This means project (or subproject) sources, external libraries and local dependencies will all be dealt with by default.

Note: This plugin may change due to the modification of transform-api. So you may keep track of RoboAspectJ to make sure you're using the most recent version.

latest version: v0.9.1

Prerequisite

Android Plugin (application) 2.1.0

Apply

Add plugin dependency in buildscript classpath:

buildscript {

  dependencies {

classpath 'com.meituan.gradle:roboaspectj:0.9.+'
  
}
 
}

Apply plugin:

apply plugin: 'com.meituan.roboaspectj'

Coding

There are basically 2 ways to write your aspects and weave them into production code:

As Source

write aspects in @AspectJ syntax under your project's java source directory. e.g. { $projectDir } /src/main/java/

As Library

compile and bundle your aspects independently using ajc, then make it dependency in build script. For example:

compile 'com.example.myaspects:library:1.0'

This way may be a little bit complicated. But it's suitable for those who want to maintain their aspects as an independent project.

Variant-Specific Concern

While RoboAspectJ is registered globally, we still can do our crosscutting concern under specific variant. Actually, this is already done by Android plugin.

As Source

put variant-specific aspects under corresponding folder.

For example, I want to do some performance monitoring in myflavor, so I will write aspects under ${ projectDir } /src/myflavor/java/.

As Library

add variant-specific aspects dependency to corresponding configuration scope.

myflavorCompile 'com.example.myaspects:library:1.0'

Configuration

There is an extension aspectj for you to do some tweaking.

Exclude

If you want to leave some artifact untouched from AspectJ, using:

aspectj {
  exclude group: 'com.google.android', module: 'support-v4' 
}

Java runtime

When applying rxjava or retrolambda, you may need jrt.jar as classpath. Configure it by:

aspectj {
  javartNeeded true 
}

Disable

For debug or performance use, you can disable weaving:

aspectj {

  enable false
 //by default, it's true and you don't have to add this statement. 
}

alternatively, set roboaspectj.enable property false when run gradle.

$ gradle clean assembleDebug -Droboaspectj.enable=false

Maybe you want it to be smarter to disable it when it's a debug flavor, then add this to your build script:

aspectj {

  disableWhenDebug true // default is false 
}

or, specify roboaspectj.disableWhenDebug property.

$ gradle clean assembleDebug -Droboaspectj.disableWhenDebug=true

Though weaving is disabled, Aspects and AspectJ compile dependencies are all still there. It's only the weaving step doesn't happen.

Note: Corresponding property has precedence over config in build script in both of these 2 cases. For instance, weaving will not take effect when your roboaspectj.enable property is false, no matter what you config in build script.