Android build configuration in Flutter - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

Understanding Android build flavors in Flutter

You have two build flavors: dev and prod. Which command builds the dev flavor APK?

A flutter build apk --flavor prod

B flutter build apk --flavor dev

C flutter run --flavor prod

D flutter run --flavor dev

💡 Hint

Use the build command with the flavor name to create the APK.

The command 'flutter build apk --flavor dev' builds the APK for the dev flavor. 'flutter run' runs the app on a device but does not create a build artifact.

🧠 Conceptual

intermediate

Purpose of build.gradle in Android Flutter projects

What is the main role of the build.gradle file inside the Android folder of a Flutter project?

A It defines Android build settings like SDK versions, dependencies, and signing configs.

B It contains Flutter Dart code for UI components.

C It manages iOS build configurations.

D It stores Flutter package dependencies.

💡 Hint

Think about what controls Android-specific build details.

The build.gradle file configures Android build parameters such as SDK versions, dependencies, and signing. Flutter Dart code and package dependencies are managed elsewhere.

📝 Syntax

advanced

Correct syntax for signing config in build.gradle

Which option correctly defines a signing config named release in the Android build.gradle file?

A

signingConfigs {
    release {
        storeFile = file('keystore.jks')
        storePassword = 'password'
        keyAlias = 'key'
        keyPassword = 'password'
    }
}

B

signingConfigs {
    release: {
        storeFile = 'keystore.jks'
        storePassword = 'password'
        keyAlias = 'key'
        keyPassword = 'password'
    }
}

C

signingConfigs {
    release {
        storeFile 'keystore.jks'
        storePassword 'password'
        keyAlias 'key'
        keyPassword 'password'
    }
}

D

signingConfigs {
    release {
        storeFile file('keystore.jks')
        storePassword 'password'
        keyAlias 'key'
        keyPassword 'password'
    }
}

💡 Hint

In Gradle Groovy DSL (used in Flutter), properties in signingConfigs blocks use no '=' and file() for paths.

Option D uses correct Gradle Groovy syntax (standard in Flutter android/app/build.gradle): storeFile file('keystore.jks') with no '='. Option D uses invalid ':', C uses '=' (for Kotlin DSL), D misses file().

❓ lifecycle

advanced

Effect of changing minSdkVersion in build.gradle

If you increase minSdkVersion in your Android build.gradle file, what is the likely effect?

A The app will not run on devices with Android versions below the new minSdkVersion.

B The app will support more devices.

C The app size will automatically decrease.

D The app will run faster on all devices.

💡 Hint

minSdkVersion sets the lowest Android version supported.

Increasing minSdkVersion means devices with older Android versions cannot install or run the app. It does not affect speed or app size directly.

🔧 Debug

expert

Diagnosing build failure due to missing keystore file

You get this error when building a release APK: FileNotFoundException: keystore.jks (No such file or directory). What is the most likely cause?

A The AndroidManifest.xml file is missing required permissions.

B The Flutter SDK is outdated and needs updating.

C The keystore file path in build.gradle is incorrect or the file is missing.

D The Dart code has syntax errors.

💡 Hint

Check the file path and existence of the keystore file.

The error clearly states the keystore file is not found. This usually means the path in build.gradle is wrong or the file is not present. Other options do not cause this error.