ProGuard and R8 optimization in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable R8 optimization in your Android app's build.gradle file.

Android Kotlin

android {
    buildTypes {
        release {
            minifyEnabled = [1]
        }
    }
}

Drag options to blanks, or click blank then click option'

Afalse

B"true"

Ctrue

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around true like "true" causes a syntax error.

Setting minifyEnabled to false disables code shrinking.

Setting minifyEnabled = true enables R8 to shrink and optimize your app code during release builds.

2fill in blank

medium

Complete the code to specify the ProGuard rules file in your build.gradle for release builds.

Android Kotlin

android {
    buildTypes {
        release {
            proguardFiles getDefaultProguardFile([1]), 'proguard-rules.pro'
        }
    }
}

Drag options to blanks, or click blank then click option'

A"proguard-default.txt"

B"proguard-android-optimize.txt"

C"proguard-rules.pro"

D"proguard-android.txt"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong file name disables optimization.

Omitting quotes causes syntax errors.

The getDefaultProguardFile("proguard-android-optimize.txt") loads the default optimized ProGuard rules for Android.

3fill in blank

hard

Fix the error in the ProGuard rule to keep all classes in the package com.example.app.models.

Android Kotlin

-keep class [1].** { *; }

Drag options to blanks, or click blank then click option'

Acom.example.app.models.**

Bcom.example.app.model

Ccom.example.app.models.*

Dcom.example.app.models

Attempts:

3 left

💡 Hint

Common Mistakes

Adding wildcards inside the package name causes errors.

Misspelling the package name prevents rules from applying.

The correct package name is com.example.app.models. The .** after it keeps all classes recursively.

4fill in blank

hard

Fill both blanks to keep all public void methods in the class com.example.app.utils.NetworkUtils.

Android Kotlin

-keepclassmembers class [1] {
    public [2] *;
}

Drag options to blanks, or click blank then click option'

Acom.example.app.utils.NetworkUtils

Bvoid

Cmethod

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'method' instead of a return type causes syntax errors.

Misspelling the class name prevents the rule from applying.

The class name is com.example.app.utils.NetworkUtils. The return type void matches public methods with no return value.

5fill in blank

hard

Fill both blanks to create a ProGuard rule that keeps all classes annotated with @Keep in the package com.example.app.

Android Kotlin

-keep @[1] class [2].** { *; }

Drag options to blanks, or click blank then click option'

Aandroidx.annotation.Keep

Bcom.example.app

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing annotation and package names.

Using incomplete package names.

The annotation is androidx.annotation.Keep. The package is com.example.app. This rule keeps all classes in that package annotated with @Keep.