Android Studio 3.1升级后Gradle项目同步失败求助

Hey there, sorry to hear you're stuck with this frustrating Gradle sync issue right after updating to Android Studio 3.1. That HttpRequestException usually points to a problem accessing Google's Maven repository, so let's walk through some tried-and-true fixes to get you back up and running:

• Verify network access and proxy settings

  • First, test if you can reach the problematic URL directly: open https://dl.google.com/dl/android/maven2/org/jetbrains/annotations/13.0/annotations-13.0.pom in your browser. If it doesn't load, your network might be blocking access to Google's Maven repo.
  • Check Android Studio's proxy config: go to File > Settings > Appearance & Behavior > System Settings > HTTP Proxy. Make sure your proxy settings are correct (if you use one), or try switching to "No proxy" temporarily to rule out proxy issues.
  • Also check your global Gradle proxy settings: open ~/.gradle/gradle.properties (on Windows it's C:\Users\<YourName>\.gradle\gradle.properties) and look for lines like systemProp.http.proxyHost — comment them out if you don't need a proxy anymore.

• Clear Gradle and IDE caches

  • Corrupted cache files are a common culprit here. Delete the .gradle/caches folder (you'll find this in your project root directory, or in your user home folder's .gradle directory).
  • Alternatively, use Android Studio's built-in tool: go to File > Invalidate Caches / Restart, then select "Invalidate and Restart". This will clear both IDE and Gradle caches in one go.

• Double-check your build.gradle repository config

  • Make sure your project's root build.gradle has the correct Google repository setup. It should look like this:

    buildscript {
        repositories {
            google()
            jcenter()
        }
        // ... other dependencies
    }
    
    allprojects {
        repositories {
            google()
            jcenter()
        }
    }
    

  • If you're still using the old maven { url 'https://dl.google.com/dl/android/maven2/' } syntax, try replacing it with google() — it's the official shorthand and less prone to typos.

• Temporarily downgrade the Gradle plugin (if needed)

  • Sometimes the latest Android Studio version has compatibility issues with older projects. You can try rolling back the Gradle plugin version in your root build.gradle:

    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1' // Switch to a stable older version
    }
    

  • Sync the project after making this change — if it works, you can later investigate what's causing the compatibility issue with 3.1.

• Check firewall/antivirus interference

  • Local firewalls or antivirus software might be blocking Android Studio's outgoing requests. Try temporarily disabling them, then run a Gradle sync again to see if that fixes the problem.

If none of these steps work, feel free to share more details from the Gradle sync log — that can help narrow down the issue further.

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