# Android Build Error: resource android:attr/lStar not found.

```
Execution failed for task ':launcher:processReleaseResources'.

A failure occurred while executing com.android.build.gradle.internal.tasks.Workers$ActionFacade
Android resource linking failed
/Users/dkt597/.gradle/caches/transforms-2/files-2.1/0d067be99fbc0369149ed6cce206a9e4/androidx.core.core-1.8.0/res/values/values.xml:104:5-113:25: AAPT: error: resource android:attr/lStar not found.

```

#### Problem Description

When building Android projects in Unity 2021 or lower, you might encounter an error related to `androidx.core:core:1.7.0`. This issue arises because Unity 2021 uses SDK build tools version 30.0.2, which does not support compiling `androidx.core:core:1.7.0`, intended for Android SDK 31 and above.

#### What You Might See

The build fails, and the error message points to a missing `android:attr/lStar` attribute, indicating an issue with the AndroidX core library version.

#### Root Cause

This build error is primarily due to a version compatibility issue between the Android SDK build tools used by Unity 2021 and the version of `androidx.core` that gets automatically resolved by Google’s External Dependency Manager. Surprisingly, even if the dependencies are explicitly set to use `androidx.core:core:1.5.0`, the External Dependency Manager overrides this to use version 1.7.0.

#### Step-by-Step Solution

1. **Disable Auto-Resolution**: First, turn off the auto-resolution feature in Unity’s Android Resolver settings to prevent it from automatically updating to incompatible versions.
2. **Remove Incompatible Version**: Manually remove the androidx.core:core:1.7.0 library that is being incorrectly added.
3. **Manually Add Compatible Version**: Download the [androidx.core:core:1.5.0](https://mvnrepository.com/artifact/androidx.core/core/1.5.0) library directly from Maven and add it manually to the Android plugins folder in the Unity project.
4. **Rebuild the Project**: After making these adjustments, the project should build successfully without any errors.

#### Alternatives and Recommendations

If you're facing this issue, you have a couple of options:

* **Manual Integration**: Follow the steps above to manually integrate the correct version of the AndroidX library.
* **Upgrade Unity**: Consider upgrading to Unity 2022 or newer. These later versions use SDK build tools version 32.0.0, which are compatible with newer AndroidX versions, thus avoiding this issue entirely.
