UE4 'Error: Unknown Error' | android launching

Question

27.2 and i want to pkg my project for android but every time it ends with:

PackagingResults: Error: Unknown Error

os: windows 10 (64x)

SDK: 29.0.2 and 28.0.3

NDK: 21.1.6352462

JDK: Eclipse Termurin JDK Hotspot 17.0.5+8 (x64)

UATHelper: Packaging (Android (ASTC)): Z:\app\src\main\java\com\epicgames\ue4\WebViewControl.java:122: error: cannot find symbol
UATHelper: Packaging (Android (ASTC)):                 webView.getSettings().setAppCacheMaxSize( 10 * 1024 * 1024 );
UATHelper: Packaging (Android (ASTC)):                                      ^
UATHelper: Packaging (Android (ASTC)):   symbol:   method setAppCacheMaxSize(int)
UATHelper: Packaging (Android (ASTC)):   location: class WebSettings
UATHelper: Packaging (Android (ASTC)): Z:\app\src\main\java\com\epicgames\ue4\WebViewControl.java:123: error: cannot find symbol
UATHelper: Packaging (Android (ASTC)):                 webView.getSettings().setAppCachePath(GameActivity._activity.getApplicationContext().getCacheDir().getAbsolutePath() );
UATHelper: Packaging (Android (ASTC)):                                      ^
UATHelper: Packaging (Android (ASTC)):   symbol:   method setAppCachePath(String)
UATHelper: Packaging (Android (ASTC)):   location: class WebSettings
UATHelper: Packaging (Android (ASTC)): Z:\app\src\main\java\com\epicgames\ue4\WebViewControl.java:125: error: cannot find symbol
UATHelper: Packaging (Android (ASTC)):                 webView.getSettings().setAppCacheEnabled( true );
UATHelper: Packaging (Android (ASTC)):                                      ^
UATHelper: Packaging (Android (ASTC)):   symbol:   method setAppCacheEnabled(boolean)
UATHelper: Packaging (Android (ASTC)):   location: class WebSettings
UATHelper: Packaging (Android (ASTC)): Note: Some input files use or override a deprecated API.
UATHelper: Packaging (Android (ASTC)): Note: Recompile with -Xlint:deprecation for details.
UATHelper: Packaging (Android (ASTC)): 3 errors
UATHelper: Packaging (Android (ASTC)): > Task :app:compileDebugJavaWithJavac FAILED
UATHelper: Packaging (Android (ASTC)): FAILURE: Build failed with an exception.
UATHelper: Packaging (Android (ASTC)): * What went wrong:
UATHelper: Packaging (Android (ASTC)): Execution failed for task ':app:compileDebugJavaWithJavac'.
UATHelper: Packaging (Android (ASTC)): > Compilation failed; see the compiler error output for details.
UATHelper: Packaging (Android (ASTC)): * Try:
UATHelper: Packaging (Android (ASTC)): Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
UATHelper: Packaging (Android (ASTC)): * Get more help at https://help.gradle.org
UATHelper: Packaging (Android (ASTC)): BUILD FAILED in 19s
UATHelper: Packaging (Android (ASTC)): 32 actionable tasks: 3 executed, 29 up-to-date
UATHelper: Packaging (Android (ASTC)): ERROR: cmd.exe failed with args /c "D:\UEPro\MyProject2\Intermediate\Android\armv7\gradle\rungradle.bat" :app:assembleDebug
UATHelper: Packaging (Android (ASTC)):        (see C:\Users\frans\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_4.27\Log.txt for full exception trace)
UATHelper: Packaging (Android (ASTC)): AutomationTool exiting with ExitCode=1 (Error_Unknown)
UATHelper: Packaging (Android (ASTC)): BUILD FAILED
PackagingResults: Error: Unknown Error

Answer 1

In Android SDK 33 setAppCacheMaxSize, setAppCachePath, setAppCacheEnabled were removed: https://developer.android.com/sdk/api_diff/33/changes

Unreal Engine has a bug that it uses the highest available Android SDK version that is installed in sdkmanager. You're probably not using SDK 29.0.2 or 28.0.3, but building it with SDK 33+.

You have 2 options here:

1. In Android Studio > SDK Manager > SDK Tools (Show Package Details must be enabled) need to uninstall all build-tools versions that are greater than a version that you want to build with (29.0.2 or 28.0.3 as you mentioned)
2. You can use SDK 33, but then you need to go to $UNREAL_INSTALL_DIR/Engine/Build/Android/Java/src/com/epicgames/ue4/WebViewControl.java and remove (comment out) these lines:

webView.getSettings().setAppCacheMaxSize( 10 * 1024 * 1024 );
webView.getSettings().setAppCachePath(GameActivity._activity.getApplicationContext().getCacheDir().getAbsolutePath() );
webView.getSettings().setAppCacheEnabled( true );