Gradle : DSL element 'useProguard' is obsolete and will be removed soon

Question

Since the 3.5 update of Android Studio, I have this warning when building my app :

DSL element 'useProguard' is obsolete and will be removed soon. Use 'android.enableR8' in gradle.properties to switch between R8 and Proguard..

Answer 1

Removing "useProguard" from build.gradle fixed the problem for me, like:

release {
            minifyEnabled true
            //useProguard true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }

Update 2022, or Details; R8 is nowadays:

• By default enabled,
• And it simply replaces ProGuard,

  But supports existing .pro files (and there should be no need to reconfigure).

• Also, any way to disable R8, or use ProGuard instead, is deprecated (or even removed).

  But debug flavors can set debuggable true, and continue to be debuggable line-by-line.

Answer 2

set the following in your project's gradle.properties file

android.enableR8=true

R8 also has full mode that is not directly compatible with Proguard. In order to try that out you can additionally set the following in your gradle.properties file

android.enableR8.fullMode=true

This turns on more optimizations, that can further reduce app size. However, you might need a few extra keep rules to make it work.

Answer 3

At a glance, when you build you project using Android Gradle plugin 3.4.0 or higher, the plugin no longer uses ProGuard to perform compile-time code optimization. Instead, the plugin works with the R8 compiler by default to handle the Shrink, obfuscate, and optimize your app. However, you can disable certain tasks or customize R8’s behavior through ProGuard rules files.

In fact, R8 works with all of your existing ProGuard rules files, so updating the Android Gradle plugin to use R8 should not require you to change your existing rules.

When you use Android Studio 3.4 or Android Gradle plugin 3.4.0 and higher, R8 is the default compiler that converts your project’s Java bytecode into the DEX format that runs on the Android platform. However, when you create a new project using Android Studio, shrinking, obfuscation, and code optimization is not enabled by default. You may enable them using the below code -

android {
    buildTypes {
        release {
            // Enables code shrinking, obfuscation, and optimization for only
            // your project's release build type.
            minifyEnabled true

            // Enables resource shrinking, which is performed by the
            // Android Gradle plugin.
            shrinkResources true

            // Includes the default ProGuard rules files that are packaged with
            // the Android Gradle plugin. To learn more, go to the section about
            // R8 configuration files.
            proguardFiles getDefaultProguardFile(
                    'proguard-android-optimize.txt'),
                    'proguard-rules.pro'
        }
    }
    ...
}

For the more adventurous, R8 also has full mode. In order to try that out you can additionally set the following in your gradle.properties file.3

android.enableR8.fullMode=true

This turns on more optimizations, that can further reduce app size. However, you might need a few extra keep rules to make it work. Learn more here - https://youtu.be/uQ_yK8kRCaA