如错误消息中所述，您需要解决/删除一些重复的类（很可能还具有不兼容的版本设置）。对于我的情况，我需要升级我的Firebase Analytics。这就是我追踪问题的方式：

我跑了

./gradlew -q app:dependencies

通过搜索play-services-测量来发现以下片段：

|    |    |    +--- com.google.android.gms:play-services-ads:21.2.0
|    |    |    |    +--- androidx.browser:browser:1.4.0
|    |    |    |    |    +--- androidx.collection:collection:1.1.0 -> 1.2.0 (*)
|    |    |    |    |    +--- androidx.concurrent:concurrent-futures:1.0.0 (*)
|    |    |    |    |    +--- androidx.interpolator:interpolator:1.0.0 (*)
|    |    |    |    |    +--- androidx.core:core:1.1.0 -> 1.8.0 (*)
|    |    |    |    |    +--- androidx.annotation:annotation:1.1.0 -> 1.3.0
|    |    |    |    |    \--- com.google.guava:listenablefuture:1.0 -> 9999.0-empty-to-avoid-conflict-with-guava
|    |    |    |    +--- androidx.collection:collection:1.0.0 -> 1.2.0 (*)
|    |    |    |    +--- androidx.core:core:1.0.0 -> 1.8.0 (*)
|    |    |    |    +--- com.google.android.gms:play-services-ads-base:21.2.0
|    |    |    |    |    \--- com.google.android.gms:play-services-basement:18.0.0 (*)
|    |    |    |    +--- com.google.android.gms:play-services-ads-identifier:18.0.0 (*)
|    |    |    |    +--- com.google.android.gms:play-services-ads-lite:21.2.0
|    |    |    |    |    +--- androidx.work:work-runtime:2.7.0 -> 2.7.1
|    |    |    |    |    |    +--- androidx.annotation:annotation-experimental:1.0.0 -> 1.1.0
|    |    |    |    |    |    +--- com.google.guava:listenablefuture:1.0 -> 9999.0-empty-to-avoid-conflict-with-guava
|    |    |    |    |    |    +--- androidx.lifecycle:lifecycle-livedata:2.1.0 -> 2.5.1 (*)
|    |    |    |    |    |    +--- androidx.startup:startup-runtime:1.0.0 -> 1.1.1 (*)
|    |    |    |    |    |    +--- androidx.core:core:1.6.0 -> 1.8.0 (*)
|    |    |    |    |    |    +--- androidx.room:room-runtime:2.2.5 -> 2.4.2 (*)
|    |    |    |    |    |    +--- androidx.sqlite:sqlite:2.1.0 -> 2.2.0 (*)
|    |    |    |    |    |    +--- androidx.sqlite:sqlite-framework:2.1.0 -> 2.2.0 (*)
|    |    |    |    |    |    +--- androidx.core:core:1.1.0 -> 1.8.0 (*)
|    |    |    |    |    |    \--- androidx.lifecycle:lifecycle-service:2.1.0 -> 2.4.0 (*)
|    |    |    |    |    +--- com.google.android.gms:play-services-ads-base:21.2.0 (*)
|    |    |    |    |    +--- com.google.android.gms:play-services-basement:18.0.0 (*)
|    |    |    |    |    +--- com.google.android.gms:play-services-measurement-sdk-api:20.1.2 (*)

|    +--- com.google.firebase:firebase-analytics:18.0.3
|    |    +--- com.google.android.gms:play-services-measurement:18.0.3
|    |    |    +--- androidx.collection:collection:1.0.0 -> 1.2.0 (*)
|    |    |    +--- androidx.legacy:legacy-support-core-utils:1.0.0 (*)
|    |    |    +--- com.google.android.gms:play-services-ads-identifier:17.0.0 -> 18.0.0 (*)
|    |    |    +--- com.google.android.gms:play-services-basement:17.0.0 -> 18.0.0 (*)
|    |    |    +--- com.google.android.gms:play-services-measurement-base:18.0.3 -> 20.1.2 (*)
|    |    |    +--- com.google.android.gms:play-services-measurement-impl:18.0.3
|    |    |    |    +--- androidx.collection:collection:1.0.0 -> 1.2.0 (*)
|    |    |    |    +--- androidx.core:core:1.0.0 -> 1.8.0 (*)
|    |    |    |    +--- com.google.android.gms:play-services-ads-identifier:17.0.0 -> 18.0.0 (*)
|    |    |    |    +--- com.google.android.gms:play-services-basement:17.0.0 -> 18.0.0 (*)
|    |    |    |    +--- com.google.android.gms:play-services-measurement-base:18.0.3 -> 20.1.2 (*)
|    |    |    |    \--- com.google.android.gms:play-services-stats:17.0.0
|    |    |    |         +--- androidx.legacy:legacy-support-core-utils:1.0.0 (*)
|    |    |    |         \--- com.google.android.gms:play-services-basement:17.0.0 -> 18.0.0 (*)
|    |    |    \--- com.google.android.gms:play-services-stats:17.0.0 (*)
|    |    +--- com.google.android.gms:play-services-measurement-api:18.0.3
|    |    |    +--- com.google.android.gms:play-services-ads-identifier:17.0.0 -> 18.0.0 (*)
|    |    |    +--- com.google.android.gms:play-services-basement:17.0.0 -> 18.0.0 (*)
|    |    |    +--- com.google.android.gms:play-services-measurement-base:18.0.3 -> 20.1.2 (*)
|    |    |    +--- com.google.android.gms:play-services-measurement-sdk-api:18.0.3 -> 20.1.2 (*)
|    |    |    +--- com.google.android.gms:play-services-tasks:17.0.0 -> 18.0.1 (*)
|    |    |    +--- com.google.firebase:firebase-common:19.3.0 -> 20.0.0 (*)
|    |    |    +--- com.google.firebase:firebase-components:16.0.0 -> 17.0.0 (*)
|    |    |    +--- com.google.firebase:firebase-installations:16.3.2 -> 17.0.0 (*)
|    |    |    +--- com.google.firebase:firebase-installations-interop:16.0.0 -> 17.0.0 (*)
|    |    |    \--- com.google.firebase:firebase-measurement-connector:18.0.0 (*)
|    |    \--- com.google.android.gms:play-services-measurement-sdk:18.0.3

所以很明显，问题出在我的项目的这两个直接依赖关系中com.google.android. gms：play-services-ads：21.2.0和com.google.fire base：fire base-analytics：18.0.3都指定了不同版本的play-services-测量

如果我们更进一步查看play-services-测量的pom文件：18.0.3：

    <dependency>
      <groupId>com.google.android.gms</groupId>
      <artifactId>play-services-measurement-base</artifactId>
      <version>[18.0.3]</version>
      <scope>compile</scope>
      <type>aar</type>
    </dependency>
    <dependency>
      <groupId>com.google.android.gms</groupId>
      <artifactId>play-services-measurement-impl</artifactId>
      <version>[18.0.3]</version>
      <scope>compile</scope>
      <type>aar</type>
    </dependency>

它严格要求18.0.3的base和impl，这使得Gradle无法自行解决问题。

我选择将Firebase分析升级到20.1.2，问题得到解决。

我通过更新pubspec. yaml中的flutter版本和更新包来解决它