16 KB Page Size Support

September 10, 2025 · View on GitHub

This Android PDF Viewer library has been updated to support 16 KB page sizes, which is required for Google Play compatibility starting November 1st, 2025.

What Changed

Build Configuration Updates

  1. Android Gradle Plugin: Already using AGP 8.13.0 (✅ above required 8.5.1)
  2. NDK Version: Updated to use NDK r28+ for 16 KB support
  3. Packaging Options: Configured to use uncompressed shared libraries for proper 16 KB alignment
  4. Gradle Properties: Added configuration for 16 KB compatibility

Key Changes Made

android-pdf-viewer/build.gradle

// 16 KB page size support configuration
packagingOptions {
    jniLibs {
        useLegacyPackaging false  // Use uncompressed shared libraries for 16 KB alignment
    }
}

// Enable 16 KB page size support for native libraries
ndkVersion "28.0.12433566"  // Use NDK r28+ for 16 KB support

sample/build.gradle

packagingOptions {
    // ... existing exclusions ...
    
    // 16 KB page size support configuration
    jniLibs {
        useLegacyPackaging false  // Use uncompressed shared libraries for 16 KB alignment
    }
}

// Enable 16 KB page size support for native libraries
ndkVersion "28.0.12433566"  // Use NDK r28+ for 16 KB support

gradle.properties

# 16 KB page size support
android.bundle.enableUncompressedNativeLibs=false
android.enableR8.fullMode=true

Native Dependencies

This library uses pdfium-android:1.9.0, which contains native libraries. The configuration ensures these libraries are properly aligned for 16 KB page sizes.

Verification

Using the Provided Scripts

Linux/macOS

./check_16kb_alignment.sh sample/build/outputs/apk/debug/sample-debug.apk

Windows PowerShell

.\check_16kb_alignment.ps1 -ApkFile "sample\build\outputs\apk\debug\sample-debug.apk"

Windows Batch Script

.\realign_apk.bat "sample\build\outputs\apk\debug\sample-debug.apk"

Python Script (Cross-platform)

python fix_16kb_alignment.py "sample/build/outputs/apk/debug/sample-debug.apk"

Manual Verification

  1. Check APK alignment:

    zipalign -c -p -v 4 your-app.apk

  2. Test on 16 KB device:

    adb shell getconf PAGE_SIZE
# Should return 16384

Fixing Alignment Issues

If your APK fails 16 KB alignment checks, use the provided realignment scripts:

  1. Copy your APK to avoid file lock issues:

    cp sample/build/outputs/apk/debug/sample-debug.apk sample-debug-copy.apk

  2. Run the realignment script:

    .\realign_apk.bat "sample-debug-copy.apk"

  3. Verify the fix:

    zipalign -c -p -v 4 sample-debug-copy.apk

Testing on 16 KB Devices

Android Emulator

  1. Download Android 15 system image with 16 KB page size support
  2. Create virtual device with the 16 KB system image
  3. Test your app on the emulator

Physical Devices

  • Pixel 8 and 8 Pro (Android 15 QPR1+)
  • Pixel 8a (Android 15 QPR1+)
  • Pixel 9, 9 Pro, and 9 Pro XL (Android 15 QPR2 Beta 2+)

Enable "Boot with 16KB page size" in Developer Options.

Benefits

Devices with 16 KB page sizes provide:

  • 3.16% lower app launch times on average
  • 4.56% reduction in power draw during app launch
  • 4.48% faster camera launch (hot starts)
  • 6.60% faster camera launch (cold starts)
  • 8% improved system boot time

Compatibility

  • ✅ AGP Version: 8.13.0 (above required 8.5.1)
  • ✅ NDK Version: r28+ (16 KB aligned by default)
  • ✅ Native Libraries: Configured for 16 KB alignment
  • ✅ Packaging: Uncompressed shared libraries for proper alignment

Resources

Troubleshooting

If you encounter issues:

  1. Verify NDK version: Ensure you're using NDK r28 or higher
  2. Check AGP version: Must be 8.5.1 or higher
  3. Run alignment check: Use the provided scripts to verify APK alignment
  4. Test on 16 KB device: Use emulator or physical device with 16 KB support

Support

For issues related to 16 KB page size support, please check:

  1. The alignment verification scripts
  2. Android Studio's APK Analyzer
  3. The official Android documentation linked above