AndResGuard

AndResGuard

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AndResGuard is a tooling for reducing your apk size, it works like the ProGuard for Java source code, but only aim at the resource files. It changes res/drawable/wechat to r/d/a, and renames the resource file wechat.png to a.png. Finally, it repackages the apk with 7zip, which can reduce the package size obviously.

AndResGuard is fast, and it does NOT need the source codes. Input an Android apk, then we can get a ‘ResGuard’ apk in a few seconds.

Some uses of AndResGuard are:

1. Obfuscate android resources. It contains all the resource type(such as drawable、layout、string…). It can prevent your apk from being reversed by Apktool.

2. Shrinking the apk size. It can reduce the resources.arsc and the package size obviously.

3. Repackage with 7zip. It supports repackage apk with 7zip, and we can specify the compression method for each file.

AndResGuard is a command-line tool, it supports Windows, Linux and Mac. We suggest you to use 7zip in Linux or Mac platform for a higher compression ratio.

How to use

With Gradle

This has been released on Bintray

apply plugin: 'AndResGuard'

buildscript {
    repositories {
        jcenter()
        google()
    }
    dependencies {
        classpath 'com.tencent.mm:AndResGuard-gradle-plugin:1.2.21'
    }
}

andResGuard {
    // mappingFile = file("./resource_mapping.txt")
    mappingFile = null
    use7zip = true
    useSign = true
    // It will keep the origin path of your resources when it's true
    keepRoot = false
    // If set, name column in arsc those need to proguard will be kept to this value
    fixedResName = "arg"
    // It will merge the duplicated resources, but don't rely on this feature too much.
    // it's always better to remove duplicated resource from repo
    mergeDuplicatedRes = true
    whiteList = [
        // your icon
        "R.drawable.icon",
        // for fabric
        "R.string.com.crashlytics.*",
        // for google-services
        "R.string.google_app_id",
        "R.string.gcm_defaultSenderId",
        "R.string.default_web_client_id",
        "R.string.ga_trackingId",
        "R.string.firebase_database_url",
        "R.string.google_api_key",
        "R.string.google_crash_reporting_api_key",
        "R.string.project_id",
    ]
    compressFilePattern = [
        "*.png",
        "*.jpg",
        "*.jpeg",
        "*.gif",
    ]
    sevenzip {
        artifact = 'com.tencent.mm:SevenZip:1.2.21'
        //path = "/usr/local/bin/7za"
    }

    /**
    * Optional: if finalApkBackupPath is null, AndResGuard will overwrite final apk
    * to the path which assemble[Task] write to
    **/
    // finalApkBackupPath = "${project.rootDir}/final.apk"

    /**
    * Optional: Specifies the name of the message digest algorithm to user when digesting the entries of JAR file
    * Only works in V1signing, default value is "SHA-1"
    **/
    // digestalg = "SHA-256"
}

Wildcard

The whiteList and compressFilePattern support wildcard include ? * +.

?	Zero or one character
*	Zero or more of character
+	One or more of character

WhiteList

You need put all resource which access via getIdentifier into whiteList. You can find more whitsList configs of third-part SDK in white_list.md. Welcome PR your configs which is not included in white_list.md

The whiteList only works on the specsName of resources, it wouldn’t keep the path of resource. If you wanna keeping the path, please use mappingFile to implement it.

For example, we wanna keeping the path of icon, we need add below into our mappingFile.

res path mapping:
    res/mipmap-hdpi-v4 -> res/mipmap-hdpi-v4
    res/mipmap-mdpi-v4 -> res/mipmap-mdpi-v4
    res/mipmap-xhdpi-v4 -> res/mipmap-xhdpi-v4
    res/mipmap-xxhdpi-v4 -> res/mipmap-xxhdpi-v4
    res/mipmap-xxxhdpi-v4 -> res/mipmap-xxxhdpi-v4

How to Launch

If you are using Android Studio, you can find the generate task option in andresguard group. Or alternatively, you run ./gradlew resguard[BuildType | Flavor] in your terminal. The format of task name is as same as assemble.

Sevenzip

The sevenzip in gradle file can be set by path or artifact. Multiple assignments are allowed, but the winner is always path.

Result

If finalApkBackupPath is null, AndResGuard will overwrite final APK to the path which assemble[Task] write. Otherwise, it will store in the path you assigned.

Other

Looking for more detail

Known Issue

1. The first element of list which returned by AssetManager#list(String path) is empty string when you’re using the APK which is compressed by 7zip. #162

Best Practise

1. Do NOT add resources.arsc into compressFilePattern unless the app size is really matter to you.(#84 #233)
2. Do NOT enable 7zip compression(use7zip) when you distribute your APP on Google Play. It’ll prevent the file-by-file patch when updating your APP. (#233)

Thanks

Apktool Connor Tumbleson

v2sig @jonyChina162