Android Studio 3.1.1项目同步失败报错：可选部分结尾无效

Hey there, let's fix that frustrating sync failure you're hitting in Android Studio 3.1.1. That error about the "invalid optional section end" at position 54 in your path is almost always tied to wonky dependency configuration—specifically placeholder syntax that Gradle can't parse correctly. Here's how to work through it step by step:

• First, inspect your app/libs directory and dependency references
  The error path shows [artifact]-[revision](-[classifier]).[ext]—those are placeholder markers, not actual filenames. Gradle interprets parentheses () as optional sections in path patterns, but your syntax here is broken, causing the parsing failure.

  • Head to your app/libs folder and check if any filenames accidentally use these placeholders, or if you've hardcoded this invalid path in your build config.

• Fix your build.gradle dependency syntax
  Open your module-level build.gradle file (usually build.gradle(Module: app)) and look for lines like this:

  implementation files('libs/[artifact]-[revision](-[classifier]).[ext]')
  

  That's invalid. Replace it with the actual filename of your library, e.g.:

  implementation files('libs/my-library-1.4.0.jar')
  

  If you want to import all JARs in libs automatically (way easier!), use this instead:

  implementation fileTree(dir: 'libs', include: ['*.jar'])
  

• Clean caches and restart Android Studio
  After fixing the config, go to File > Invalidate Caches / Restart and select Invalidate and Restart. This clears any corrupted cached data that might be sticking around. Once Studio reopens, click the "Sync Project with Gradle Files" button to try syncing again.

• Check for special characters in your project path
  Your project path has Chinese parentheses （ssc) and spaces (v1.4). While newer Android Studio versions handle these better, 3.1.1 is pretty old and might struggle with non-standard path characters. If the above steps don't work, try moving your project to a simpler path like /Users/xxx/Desktop/project2017/xxx/ssc_v1.4/proj.androidstudio (no spaces or special symbols) and re-sync.

内容的提问来源于stack exchange，提问作者ColorfulDark