Gradle同步报错：无法解析com.android.support:design:26.1.0依赖

Hey there, let's get those dependency resolution errors sorted out! The issue you're seeing—unable to resolve com.android.support:design:26.1.0 for both debug and debugAndroidTest classpaths—almost always happens because Gradle can't find the library in your configured repositories. Here's how to fix it step by step:

1. Add Google's Maven Repository to Your Root Build.gradle #

Starting with Android Support Library 26+, Google moved these libraries from JCenter to their own Maven repository. You need to make sure your project's root build.gradle includes this repository in both the buildscript and allprojects blocks:

buildscript {
    repositories {
        google() // Shorthand for Google's official Maven repository
        jcenter()
    }
    dependencies {
        // Use a Gradle plugin version compatible with compileSdk 26 (3.0.0 or higher)
        classpath 'com.android.tools.build:gradle:3.0.1'
    }
}

allprojects {
    repositories {
        google() // Don't miss adding this here too!
        jcenter()
    }
}

If your Gradle plugin version is older than 3.0.0 (which doesn't support the google() shorthand), replace google() with:

maven { url 'https://maven.google.com' }

2. Verify Your App Module's Dependency Declaration #

Double-check that your app-level build.gradle has the correct dependency line for the design library. For compileSdk 26, it should look like this:

dependencies {
    // ... other dependencies in your project
    implementation 'com.android.support:design:26.1.0'
    // If you're using an older Gradle version, use 'compile' instead of 'implementation'
}

Your existing compileSdkVersion and targetSdkVersion are already set to 26, which matches the library version—great, that part is already correct.

3. Clean Gradle Caches and Refresh Dependencies #

Sometimes cached data can cause unexpected resolution issues. Try these steps:

• Run this command in your project root directory: ./gradlew clean build --refresh-dependencies
• Or, in Android Studio, go to File > Invalidate Caches / Restart... and select "Invalidate and Restart"

Why This Happens #

Before version 26, Android Support Libraries were hosted on JCenter, but Google shifted them to their own Maven repository to better manage updates and compatibility. Without including this repository in your project configuration, Gradle has no way to locate the com.android.support:design:26.1.0 library.

内容的提问来源于stack exchange，提问作者user8089855