Fixing Android's "Namespace Not Specified" Error

Problem Statement

When upgrading to Gradle 8.0+ in Android development, you may encounter the error:

Namespace not specified. Please specify a namespace in the module's build.gradle file

This occurs because Android Gradle Plugin (AGP) 8.0 and higher requires explicit namespace declarations in build files, replacing traditional AndroidManifest.xml package declarations. The issue often persists even after adding the namespace declaration, as third-party dependencies may lack this configuration.

Solutions

1. Add Namespace to App Module (Primary Fix)

Ensure your app-level build.gradle specifies the namespace in the android block:

android {
    namespace "com.example.yourapp" // Must match applicationId
    // other configurations...
}

• Must be in the app module's build.gradle (android/app/build.gradle)
• The namespace should match your applicationId in defaultConfig
• AGP can automatically migrate manifest package attributes using the AGP Upgrade Assistant

WARNING

Do NOT place this in project-level build.gradle. Only the app module's file (or other Android library modules) require it.

2. Configure Namespaces for Dependencies (Common Fix)

Many errors originate from third-party dependencies lacking namespaces. Add this script to your project-level build.gradle:

subprojects {
    afterEvaluate { project ->
        if (project.hasProperty('android')) {
            project.android {
                if (namespace == null) {
                    namespace project.group
                }
            }
        }
    }
}

This auto-sets namespaces in dependencies using their group IDs. Apply this in: android/build.gradle

3. Update Outdated Plugins and Dependencies

Older plugins often cause namespace conflicts. Check for discontinued/outdated packages:

1. Run in terminal:

flutter pub outdated

2. Check pubspec.yaml for warnings like:

connectivity: 3.0.6 (discontinued)

3. Replace outdated packages with modern alternatives:

   • package_info → package_info_plus
   • connectivity → connectivity_plus

4. Upgrade plugins:

flutter pub upgrade --major-versions

4. Verify Java Compatibility

Gradle 8.0+ requires JDK 17:

1. Confirm JDK version:

java --version

2. If using JDK 18+, either:
   • Downgrade to JDK 17
   • Alternatively, downgrade Gradle (temporary fix):

distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-bin.zip

Complete Configuration Example

android/build.gradle

// Top-level build.gradle
subprojects {
    afterEvaluate { project ->
        if (project.hasProperty('android')) {
            project.android {
                if (namespace == null) {
                    namespace project.group
                }
            }
        }
    }
}

android/app/build.gradle

android {
    namespace "com.example.yourapp" // Must match applicationId
    
    defaultConfig {
        applicationId "com.example.yourapp"
        // ... other configs
    }
    // ... rest of android block
}

AndroidManifest.xml

<manifest 
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.yourapp"> <!-- Optional after namespace declaration -->
    <!-- ... -->
</manifest>

Explanation

• Why namespace?: AGP 8.0+ uses Gradle namespaces instead of manifest packages for resource collision prevention
• Dependencies matter: 80% of reported issues come from unupdated plugins
• Java compatibility: Build errors may surface when using JDK >17 with current AGP versions
• Multi-module projects: The subprojects script is necessary when module dependencies lack namespace configurations

Pro Tip

Run AGP's migration tool for automated fixes:

1. Refactor > Migrate to AGP... in Android Studio
2. Follow the AGP Upgrade Assistant

Following these solutions ensures compliance with modern Android build requirements while resolving dependency conflicts causing the namespace error. Start with adding the namespace to your app module, then configure the subprojects script before checking dependency updates.