Android Gradle 4.1同步失败求助：升级SDK等组件后无法同步

Hey there, let's work through these Gradle problems together. Based on your error messages and the build.gradle file you shared, here are actionable steps to resolve both the path canonical error and the appcompat duplicate version issue:

1. Resolve the "path must be canonical" Error #

• Clean up cached files first: Delete the .gradle folder (in your project root directory) and the build folders (both the project-level and app-module-level ones). These folders store cached build data that might be corrupted after your upgrade. Restart Android Studio after deleting them, then try syncing again.
• Check for jar file typos: Take a close look at the problematic additionnal.jar—is that a typo? It should likely be additional.jar. Incorrect file names can throw off Gradle's path parsing, even if you moved the files to a simpler directory.
• Replace fileTree with explicit jar references: Instead of using compile fileTree(include: ['*.jar'], dir: 'libs'), try referencing each jar in your libs folder individually. For example:

  compile files('libs/additionnal.jar')
  compile files('libs/other-problematic.jar')
  // Add other jars from libs here
  

  This narrows down whether the issue is with how fileTree is resolving paths.

2. Fix the AppCompat Duplicate Version Conflict #

• Inspect your full dependency tree: Open Android Studio's Terminal and run this command (Windows users omit the ./):

  ./gradlew app:dependencies
  

  This will show you every dependency your project uses, including indirect ones. Look for entries under appcompat-v7:27.0.2—you'll be able to see which other libraries are pulling in the same version, causing the conflict.
• Exclude duplicate dependencies: If you find a library that's bringing in appcompat unnecessarily, add an exclusion rule to its dependency line. For example:

  compile 'com.example.somelibrary:xxx:1.0' {
      exclude group: 'com.android.support', module: 'appcompat-v7'
  }
  

• Ensure consistent support library versions: All Android Support libraries (like appcompat, support-v4, etc.) should use the same version. Double-check that any other support-related dependencies in your build.gradle match 27.0.2.

3. Verify Gradle Plugin & Repository Settings #

• Match Gradle plugin version to compileSdk: Since you're using compileSdkVersion 27, your project-level build.gradle should use a compatible Gradle plugin version (at least 3.0.0). Update the buildscript dependency like this:

  buildscript {
      repositories {
          google()
          jcenter()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:3.0.3'
      }
  }
  

• Use official repositories: Replace the Maven Apache repo with google() and jcenter() in both your project-level and app-module build.gradle files. The Android Support libraries are hosted primarily in the Google repository, which will ensure reliable dependency downloads.

Try these steps one by one—start with cleaning the cache, as that often fixes weird post-upgrade issues. If one step doesn't work, move to the next.

内容的提问来源于stack exchange，提问作者Silvio Tamaso D'Onofrio