Android编译报错：Program type already present及无法合并dex问题求助

Hey there! Let's work through these Android dependency issues step by step—they're really common, so don't stress too much.

1. 处理"Configuration 'compile' is obsolete"警告 #

This one's straightforward: the compile configuration was deprecated in newer Gradle versions, replaced by implementation (or api if you need the dependency to be exposed to other modules). Just go through your dependencies block and replace every instance of compile with implementation. For example:

// 旧写法
compile 'com.android.support:appcompat-v7:28.0.0'

// 新写法
implementation 'com.android.support:appcompat-v7:28.0.0'

2. 解决"Program type already present: android.support.v7.util.AsyncListUtil$DataCallback"错误 #

This error means the same class is being included in your app multiple times—usually from duplicate dependencies. Here's how to fix it:

• Check your libs folder: If there's a JAR file related to android.support.v7 (like appcompat-v7.jar) in there, delete it. You're already using remote implementation dependencies, so having the JAR causes duplication.
• Find duplicate dependencies: Run this command in your terminal to generate a dependency tree:

  # macOS/Linux
  ./gradlew app:dependencies
  
  # Windows
  gradlew app:dependencies
  

  Look for entries related to android.support.v7—you'll likely see the same library being pulled in by multiple dependencies.
• Exclude duplicate dependencies: If a third-party library is bringing in an old or duplicate version of the support library, exclude it when declaring that dependency. For example:

  implementation('com.example:third-party-lib:1.2.3') {
      exclude group: 'com.android.support', module: 'appcompat-v7'
  }
  

• Align all support library versions: Make sure every com.android.support dependency in your build.gradle uses the exact same version. Mixing versions (e.g., appcompat-v7:28.0.0 and recyclerview-v7:27.1.1) often causes these duplicate class errors.

Bonus: Fixing the original "unable to merge dex" issue #

That initial dex merge error is almost certainly linked to the duplicate class problem. Once you resolve the duplicate dependencies, the dex merge issue should disappear automatically.

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