16KB Support

Author: xposed73

16KB_SUPPORT.md

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+# 16 KB Page Size Support
+
+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
+```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
+```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
+```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
+```bash
+./check_16kb_alignment.sh sample/build/outputs/apk/debug/sample-debug.apk
+```
+
+#### Windows PowerShell
+```powershell
+.\check_16kb_alignment.ps1 -ApkFile "sample\build\outputs\apk\debug\sample-debug.apk"
+```
+
+#### Windows Batch Script
+```batch
+.\realign_apk.bat "sample\build\outputs\apk\debug\sample-debug.apk"
+```
+
+#### Python Script (Cross-platform)
+```bash
+python fix_16kb_alignment.py "sample/build/outputs/apk/debug/sample-debug.apk"
+```
+
+### Manual Verification
+
+1. **Check APK alignment**:
+   ```bash
+   zipalign -c -p -v 4 your-app.apk
+   ```
+
+2. **Test on 16 KB device**:
+   ```bash
+   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:
+   ```bash
+   cp sample/build/outputs/apk/debug/sample-debug.apk sample-debug-copy.apk
+   ```
+
+2. **Run the realignment script**:
+   ```bash
+   .\realign_apk.bat "sample-debug-copy.apk"
+   ```
+
+3. **Verify the fix**:
+   ```bash
+   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
+
+- [Android 16 KB Page Size Guide](https://developer.android.com/guide/practices/page-sizes)
+- [Google Play 16 KB Requirement](https://android-developers.googleblog.com/2025/05/prepare-play-apps-for-devices-with-16kb-page-size.html)
+- [APK Analyzer Tool](https://developer.android.com/studio/build/analyze-apk)
+
+## 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