buildscript {
    repositories {
        jcenter()
        //1. 加入Jitpack仓库
        maven { url 'https://jitpack.io' }
    }
    dependencies {
        ...
        //2. 加入obfuscator-plugin 插件  
        classpath 'com.github.helen-x:obfuscator-plugin:1.0'
    }
}

//使用混淆插件  
apply plugin: 'obfuscator-plugin'

@ObfuscateKeepPublic
public class TestAnnotationKeepPublic{
}

@ObfuscateKeepAll
public class TestAnnotationKeepAll {
}

public class TestInterfaceKeep implements IObfuscateKeepAll{
}

public class TestAnnotationKeepThisField {
    
    public String sName;
    public static String sSName;
    private int iValue;
    
    @ObfuscateKeepThisField
    private static int iSValue;
    
    @ObfuscateKeepThisField
    private void tFunc(){
    }
}

@ObfuscateKeepSetterGetter
public class TestAnnotationKeepSetterGetter {}