您目前无法导出自包含的 Android 库 jar，并宣布将在未来的 SDK 版本中提供.
https://developer.android.com/guide/developing/projects/index.html#LibraryProjects

You cannot export self-contained Android Library jar at this time and announced will be available in the future SDK release.
https://developer.android.com/guide/developing/projects/index.html#LibraryProjects