Windows项目移至MacBook后Android应用无法运行，求解决方案

Hey there! As a fellow Android dev, I know how frustrating it is when a project works perfectly on one system but breaks after migration—especially when you're just starting out. Let's break down how to fix this KotlinNullPointerException that's causing your Gradle configuration error:

1. Clear Caches & Resync Gradle (First Step!) #

Cross-system migrations often leave behind corrupted cache files that mess up Gradle. Let's wipe them clean:

• Click File at the top of Android Studio → select Invalidate Caches...
• Check the box for Invalidate and Restart, then confirm. Wait for Studio to restart fully.
• Once restarted, click the elephant icon (Sync Project with Gradle Files) in the top-right corner to resync your project.

2. Check Kotlin Version Configuration #

A common culprit is mismatched or incorrectly referenced Kotlin versions between systems. Let's verify:

• Open your project-level build.gradle file (the one in the root folder, not the app subfolder)
• Make sure the ext.kotlin_version is set correctly and matches what you used on Windows. Example:

  buildscript {
      ext.kotlin_version = "1.8.22" // Use the same version as your Windows project
      repositories {
          google()
          mavenCentral()
      }
      dependencies {
          classpath "com.android.tools.build:gradle:7.4.2"
          classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
      }
  }
  

• Then open your app-level build.gradle and confirm the Kotlin plugin is applied correctly:

  plugins {
      id 'com.android.application'
      id 'org.jetbrains.kotlin.android' // No typos here!
  }
  

3. Fix Case Sensitivity Issues (Critical for Mac!) #

Windows ignores file name case, but Mac is case-sensitive. This can cause Gradle to fail finding files, leading to null pointers:

• Double-check all file names and their references in your code. For example:
  • If you have a file named UserProfile.kt on Windows, make sure it's not renamed to userprofile.kt on Mac.
  • Verify imports in Kotlin files, layout references, and resource names all match the actual file case exactly.

4. Verify Gradle Wrapper Version #

Ensure your Mac is using the same Gradle version as your Windows project:

• Open gradle/wrapper/gradle-wrapper.properties
• Check the distributionUrl line—make sure it's identical to what was in your Windows project. Example:

  distributionUrl=https\://services.gradle.org/distributions/gradle-7.5-bin.zip
  

• If it's different, update it and resync the project.

5. Fix Android SDK Path in local.properties #

The local.properties file (auto-generated on Windows) might have an invalid SDK path for Mac:

• Open the local.properties file in your project root. If it doesn't exist, create it.
• Set the correct SDK path for Mac. It usually looks like this:

  sdk.dir=/Users/YourMacUsername/Library/Android/sdk
  

  Replace YourMacUsername with your actual Mac user name.

6. Last Resort: Re-Import the Project #

If none of the above works, a fresh import can resolve hidden configuration issues:

• Close Android Studio completely.
• Delete the .gradle, .idea folders, and the app/build folder from your project directory.
• Reopen Android Studio, select Import Project, and choose your project's root build.gradle file. Let Studio reconfigure everything from scratch.

内容的提问来源于stack exchange，提问作者wilrus